NXcrypt

• NXcrypt is a polymorphic 'python backdoors' crypter written in python by Hadi Mene (h4d3s) . The output is fully undetectable .

• NXcrypt can inject malicious python file into a normal file with multi-threading system .

• Run it with superuser's permissions .

• NXcrypt output is Fully undetectable .

Backdooring Module :

Encryption Module

Usage :

• sudo ./NXcrypt.py --file=backdoor.py --output=output_backdoor.py # encrypt backdoor.py and output file is output_backdoor.py
• sudo ./NXcrypt.py --file=shell.py # encrypt shell.py and default output file is backdoor.py but you can edit it in source code
• sudo ./NXcrypt.py --help # NXcrypt help
• sudo ./NXcrypt.py --backdoor-file=payload.py --file=test.py --output=hacked.py # inject payload.py with test.py into hacked.py with multi-threading system

How it work ?

• Encryption module :

• NXcrypt add some junkcode .
• NXcrypt use a python internal module 'py_compile' who compile the code into bytecode to a .pyc file .
• NXcrypt convert .pyc file into normal .py file .
• And in this way we can obfuscate the code
• The md5sum will change too

• Injection module :

• it inject a malicious python file into a normal file with multi-threading system .

Test with Virustotal

Before :

SHA256: e2acceb6158cf406669ab828d338982411a0e5c5876c2f2783e247b3e01c2163 File name: facebook.py Detection ratio: 2 / 54

After :

SHA256: 362a4b19d53d1a8f2b91491b47dba28923dfec2d90784961c46213bdadc80add File name: facebook_encrypted.py Detection ratio: 0 / 55

Credits

All Credits go to Suspicious Shell Activity team

Video Tutorial

https://www.youtube.com/watch?v=s8Krngv2z9Q