Full solution is found [here](https://github.com/happysox/CTF_Writeups/tree/master/RITSEC_CTF_2018/reverseme) (co-author [ludvigknutsmark](https://github.com/ludvigknutsmark))
TLDR: 
* In the binary the plaintext has been replaced with XXXXXXXXXXXXXXXX* In the core dump the key has been replaced with YYYYYYYYYYYYYYYY
Solution:Decrypt the ciphertext from the core dump with the key found in the binary
```python#!/usr/bin/python2from Crypto.Cipher import AESfrom binascii import unhexlify
def decrypt(key, cipher_text):    aes = AES.new(key)    plaintext = aes.decrypt(cipher_text[:16])    return plaintext
cipher_text = unhexlify("a629fc7035ccd2df99fb42ebc25e4f9f")print decrypt("ITSTHECRYPTOKEY!", cipher_text)```
```$ ./solution.pyRITSEC{AESISFUN}```