Flare-On 2017

08-09-2017 at night I just knew that flare-on started, solved two challenges and fall asleep.

1- The first challenge is quite easy to solve since the rotate is symmetric:

2 - This a little bit tricky since you will reproduce a small decryption algorithm to do reverse the encryption:

09-09-2017 after-noon, started solving challenge 3.

3 - This challenge requires you to find a byte value that is the key to decrypt an x86 code, given a simple hash function, once this code is decrypted and begin running, it will put the flare-on flag on the stack, so we must do 2 things:


  • Find the byte key:


  • Send that byte to the local server at 127.0.0.1:2222 and debug

09-09-2017 - 10-09-2017,

4 - It took me more time to figure out that the challenge uses PE files from last year flare-on challenge (2016). Generally, every PE file contain a 8-byte forming a part of the key, each file will have those bytes at offsets 0x400, 0x410, 0420 or 0x430.

The files should be put at the following folder:


Once the files put, you have to reverse the timestamp checks only for the running file, not the mapped files from last year challenges, a key.bin file will be created, the challenge will be solved then.


11-09-2017 - 14-09-2017, That pew challenge took me more time to solve, it has more tricks that you should figure out how to solve, just know the method and burn the challenge.




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