Full solution of Batman Investigation II - Gotham Underground Corruption from bi0sctf 2024

tl;dr

• Challenge 1 of Batman Investigation series
• Memory Forensics - WinDBG Dump Debugging - Malware Analysis - Incident Response - Threat Hunting

tl;dr

• Analysis of eBPF assembly
• Simple optimization

tl;dr

• Binary obfuscation with hidden anti-debug checks
• Linear Cryptanalysis (AES with linearly dependent SBOX)

tl;dr

• Custom hook to syscall 0x31337 using eBPF
• Check on the argument passed to syscall to verify correct/incorrect key

tl;dr

• DOM Clobbering to Redirect to another page
• Increasing Content using SQL Injection giving the same column multiple times
• Connection-Pool XS-Leaks to measure the time for the page to load
• Leak the flag character by character using the above techniques

tl;dr

• The VM takes a custom binary as input
• Binary contains function table, code and bss sections
• Code can overlap with bss and be modified at runtime
• The JIT compiler assumes that a function is safe since it ran many times
• Functions modified right before JIT bypass security checks

tl;dr

• The patch adds a vulnerable virtio device
• The device accesses pointers without bound check
• Abuse OOB pointer access to setup arb r/w primitive
• Craft open,read,write ropchain on heap
• Overwrite virtqueue handler with stack pivoting gadget

tl;dr

• Sanitizing request causes null byte overflow which corrupts type
• Processing corrupted request doesn’t remove it from incoming_queue
• Reaping corrupted request still leaves it in incoming_queue causing UAF
• Setup crosscache to abuse UAF
• UAF provides free primitive through double reset

tl;dr

• Capturing the flag id through redos attack in /search endpoint
• XSS in /uuid/noteid/raw and HTML injection in /uuid/noteid
• CSP frame-src bypass through server side redirect

tl;dr

• Implemented two SEH and two VEH Exception Handlers
• Two stage malware challenge with process injection technique
• CPP binary where logic is wrapped in classes and their member functions