2023from public repositories
GreHack 2023
3 challenges with 3 published solutions between them. CTFtime has no listing for this event at all, so nothing built on CTFtime can show what it was made of. These writeups were found in public repositories instead. Each link is pinned to the commit it was read from.
Where these writeups liveWeb1
Reach data or functionality the application meant to keep from you - through its inputs, its tokens, or its trust in the client.
Solve it with:JWT decoder and signature verifierJWT alg=none bypass generatorWeb attack payload catalogJWT secret brute forceLearn: Web attacks and session tokens
GogoPowerRangers Web Easy
1 official solution
Reverse engineering1
Work out what a compiled program does without its source, then work backwards from the check to the input that passes it.
Solve it with:Strings extractor for binaries and blobsWebAssembly disassemblerJava .class disassemblerPython .pyc bytecode disassemblerLearn: Binary exploitation
Guessing2 Reverse
1 official solution
Forensics1
Recover something from a file, a capture, or a disk image - often from a part of it the format says is unused.
Solve it with:File type identifier by magic bytesMagic byte and file signature tablePCAP analyzer for CTF network forensicsEXIF metadata viewerLearn: File forensics and carvingLearn: Network forensics
TheMadHatter Forensic Medium
1 official solution