Eat the Cake! [rev, 641 solvers] TLDR; Simple re challenge written in C++, which checks every character of the input. Despite used language, it's easily reversible doing only static analysis. At the start of the challenge I was given one file called cake.exe. Quick file check revealed that it’s UPX packed binary. To unpack it I used standard tool available in kali repositories: ➜ upx -d cake.exe Ultimate Packer for eXecutables Copyright (C) 1996 - 2018 UPX 3.

Package2 [re, 20p, 27 solves] TLDR; obfuscated .Net binary which was decrypting hardcoded, encrypted password with hardcoded key. I used avaliable deobfuscator, did some reversing, found encypted password and hardcoded key and wrote simple python script that decrypted it. To decompile this binary I used dnSpy. When I loaded it to the decompiler I saw that function and variables names are obfustaced and consists of unicode characters like \u200C\u200B\u202E\u206C\u202C\u202B\u202D.... After looking around for a bit I found interesting thing in binary metadata: