I took the day off today to solve the Fire Eye Reversing FlareOn challenges [1] and decided to publish my notes here. These challenges were very entertaining and I strongly recommend to anyone who is interested in reversing for fun.
In total, there are 11 challenges with different levels of difficult and covering the most diverse kind of technologies (from .NET to mobile reversing). This post goes through solutions for the first 3 challenges.
In total, there are 11 challenges with different levels of difficult and covering the most diverse kind of technologies (from .NET to mobile reversing). This post goes through solutions for the first 3 challenges.
.::[ Challenge 01
This challenge is a win32 executable and basically validates a password inputed by the user. If the password is correct the binary outputs a flag otherwise an error.
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Figure 01: Challenge 01 XOR encryption scheme |
By analyzing the code we realize that the binary compares the user input with an encrypted string located at address "0x00402140". This string has 24 characters (according comparison at the address "0x0040105e") and is the targeted flag in this challenge.