[ExpDev] Custom Go Crypter

What is Crypter?

A crypter is a software that can encrypt, obfuscate and manipulate malware or a RAT (Remote Access Tool) tool to potentially bypass security products such as anti-viruses.

Encryption Process

For creating a simple crpyter, I will be using the following process:

• Generate a key with random characters & seed (32 characters hard-coded as of now)
• AES Encrypt #1 — Initialize the state array with the block data using the key
• AES Encrypt #2 — Generate IV (Initialization Vector) using block size + length of shellcode
• AES Encrypt #3 — Run the encryption process using the block and IV
• Base64 encode the results

Decryption Process

• Base64 decode the results
• AES Decrypt #1 — Initialize the state array with the block data using the key
• AES Decrypt #2 — Check if length IV is equal to the block size
• AES Decrypt #3 — Run the decryption process using the block and IV
• Return the decrypted string

I chose Go programming language to create the crypter.

Generate Key Code