loeschzwerg / uni-ctf-2023

Official writeups for University CTF 2023: Brains & Bytes

Challenges

Category	Name	Objective	Difficulty [⭐⭐⭐⭐⭐]
Web	GateCrash	SQL injection via CRLF injection	⭐
Web	Nexus Void	Dotnet deserialisaiton via SQL injection	⭐⭐
Web	PhantomFeed	Race condition via reDos, open-redirect in Nuxt.js to perofrm CSRF and leak OAuth 2 access token, RCE in Reportlab	⭐⭐⭐
Pwn	Great Old Talisman	Overwrite exit@GOT with the address of the function that reads the flag	⭐
Pwn	Zombienator	Make 9 allocations and 8 frees to leak a libc address, abuse scanf("ld") to bypass the canary check, use pwntools struct to pack doubles, and perform a ret2libc attack with one gadget	⭐⭐
Pwn	Zombiedote	Leverage a single malloc call, an out of bounds read and two out of bounds writes in order into code execution in glibc 2.34	⭐⭐⭐
Reversing	WindowOfOpportunity	Reversing simple flag checker algorithm	⭐
Reversing	BioBundle	Reversing a flag checker embedded in a library encrypted and loaded with memfd_create	⭐⭐
Reversing	RiseFromTheDead	Reversing a flag encoder then recovering a core dump to retrieve the flagg	⭐⭐⭐
Forensics	One Step Closer	Windows JScript deobfuscation - Malware delivery - VBS debugging	⭐
Forensics	ZombieNet	OpenWrt firwmare analysis - MIPS binary emulation using QEMU	⭐⭐
Forensics	Shadow of the Undead	Meterpreter parsing/decryption - custom windows shellcode emulation	⭐⭐⭐
Crypto	MSS	Use CRT to get the entire secret on a Mignotte Secret Sharing scheme	⭐
Crypto	Mayday Mayday	Factor N by exploiting the partial leakage of the CRT components	⭐⭐
Crypto	Zombie Rolled	Solve a diophantine equation to get the private key and apply LLL to recover the flag from the signature	⭐⭐⭐