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Cyber Security Notes
  • Introduction
  • CVEs
    • CVE-2022-33106
  • Paper Reviews
    • Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice
  • Security Basics Notes
    • Identification, Authentication and Authorization
  • Enumeration and Initial Compromise
    • Methodology
    • Footprinting
    • Network Protocols
      • FTP
      • SMB
      • DNS
      • NFS
      • SMTP
      • IMAP/POP3
      • SNMP
      • MySQL
      • MSSQL
      • Oracle TNS
      • IPMI
    • Nifty One Liners
    • Brute-Force Web Pages
      • Hydra
    • Network Pentest
      • Quick SMB cheatsheet
      • SSH keypair basics
      • Compromise using SSH Key
      • Networking fundamentals Interview topics
      • nmap quick cheatsheet
    • Web Pentest
      • Web Pentest Interview top topics
      • Wordpress Exploitation
      • Joomla Exploitation
      • Login Bypass using Cookie Tampering/Poisoning
      • Subdomain Enumeration
      • CSRF mitigation
      • XSS mitigation
      • CSP bypass with JSONP
      • PHP Vulnerabilities
      • Python Serialization Vulnerabilities - Pickle
      • SQL Injections
      • SSTI
      • XSS
    • Buffer Overflow Prep
      • Understanding CPUs
      • Virtual Memory and Paging
      • Syscalls
      • Theorem Proving
      • Stripping readable function names
      • Insecure C functions
      • Stack Canaries
      • Linking - GOT,PLT
      • Return Oriented Programming
    • Active Directory - Basics
      • AD DS
      • Managing OUs
      • Group Policies
      • Authentications
      • Trees, Forests and Trusts
      • Kerberos
      • Attacking Kerberos
      • Priv Esc (Post Exploitation)
    • DNS/Domain Enum Masterguide
  • Post Exploitation
    • Shell Escape Techniques
    • Getting stable shell after compromise
    • Linux Privilege Escalation
      • Sudoers file
      • Sudoers entry - Yum
      • Wildcards - Basics
      • Wildcards - Chown
      • Wildcards - Tar
      • Linux Permissions & SUID/SGID/Sticky Bit
      • SUID - nmap
      • SUID - bash
      • SUID - man
      • NFS no_root_squash
      • SUID - pkexec
      • Bad permissions
    • Windows Privilege Escalation
      • SeImpersonatePrivilege Token Impersonation
      • Firefox Creds
      • Potatoes
      • Print Spooler Basics
      • Print Spooler CVE 2020-1030
      • SpoolFool
    • Data Exfiltration Post Exploitation
  • Port Forwarding Cheatsheet
  • Powershell Essentials
    • Powershell Basics
    • Powershell Enumeration
    • Powershell Port Scanner
    • Powershell One Liner Port Scanning
    • Powershell Port Scan in a given CIDR
  • Application Security
    • System Calls in Linux
    • Buffer Overflow Defenses
    • Format string vulnerabilities
    • Sample Github Actions
    • Basic Bugs in Demo Application
    • Using AFL++
  • Linux 64-bit Assembly
    • GDB Basics
      • My relevant GDB cheatsheet
      • Task 1 - Tamper strcmp logic
      • Breakpoints
      • Always starting with intel flavor
      • GDB TUI Mode
    • Basic Hello World Program
    • Registers in 64-bit
    • global directive
    • Reducing instructions and Removing NULL-> Optimizing memory in Assembly
    • Data Types
    • Endianness
    • Moving Data
    • push, pop, and the stack
    • Analysis - Writing data on memory location and referencing
    • Arithmetic Operations
    • Bitwise Logical Operations
    • Bit-Shifting Operations
    • Control Instructions
    • Loops
    • Procedures
    • Stack-Frames and Procedures
    • String Operations
    • Shellcoding basics
      • Introduction and Common Rules
      • Basic Shellcodes->Exit
      • Testing shellcode->Skeleton Code
      • Techniques-> JMP,CALL,POP
      • Techniques-> Stack
      • Techniques-> (64-bit only) RIP Relative Addressing
      • Shellcode 1 -> execve(/bin/sh) STACK PUSH
      • Shellcode 1 -> execve(/bin/sh) JMP CALL POP
      • Techniques-> XOR-Encoder
  • Cloud Security
    • Foundational Technology
    • Learning Through Project Omega
    • IAM Essentials
      • Deep dive into IAM - Part 1
    • Amazon S3
    • Risk Management & Data Controls
    • Enumeration
      • S3 - Enum Basics - PwnedLabs
      • S3 - Identify the AWS Account ID from a Public S3 Bucket
      • EBS - Loot Public EBS Volumes
      • S3- Exploit Weak Bucket Policies for Privileged Access
  • API Security
    • WSDL
  • Reverse Engineering
    • Some string Operations
    • Numbers and Inputs
    • Address inputs
    • Recursive Function
    • Crackme: level1
    • Crackme: level2
    • CTF: Memory Dereferencing
    • CTF: Monty Python
  • CTF Challenge Learnings
    • vsCTF 2024
      • Sanity Check
      • not-quite-caesar
      • Intro to reversing
    • NCL Individual 2024
      • Web Challenges
        • PiratePals
        • Pierre's Store
    • Pico CTF 2024
      • Web Exploitation
        • Bookmarklet
        • WebDecode
        • Unminify
        • Trickster
      • General Skills
        • Commitment Issues
        • Time Machine
        • Blame Game
        • Collaborative Development
        • Binary Search
        • Dont-you-love-banners
    • Sunshine CTF
      • Knowledge Repository
    • Amazon WiCys CTF
      • I am Lazy
      • Password Locker on the Web
      • Happy Birthday Card Generator
      • Bloggergate
      • simple offer
      • Bad Actor
      • Secret Server
      • Simple PCAP
      • Hidden Message
    • C code using getenv()
    • Command Injection with filter
    • Pwning
      • Shoddy_CMP
      • PLT_PlayIT
  • Applied Cryptography
    • Linear Congruential Generator
  • Tools for everything
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  1. CTF Challenge Learnings
  2. Amazon WiCys CTF

Happy Birthday Card Generator

PreviousPassword Locker on the WebNextBloggergate

Last updated 1 year ago

Was this helpful?

The website was simply accepting a name and generating a card.

I tried to input HTML tags, it didn't work. Then I used command injections, again no luck.

But then I saw the backend server was Python based. You know what the first instinct is after that?

Server Side Template Injection!

I tried the following payload:

{{10*10}}

{{"foo".class.base.subclasses()[182].init.globals['sys'].modules['os'].popen("ls /").read()}}

I replaced the ls / command in payload by cat /flag.txt and got the flag!

As we can see, SSTI PoC worked! Let's try and read /flag.txt. I used the following payload inspired from here:

https://secure-cookie.io/attacks/ssti/#tldr---show-me-the-fun-part