Polymorphic obfuscation algorithm involves several complex techniques to ensure the code changes its form each time it is executed, while maintaining its original functionality. Here’s a detailed overview and an example of how you might implement such an algorithm.
-
Code Obfuscation:
- Use encryption, compression, or other obfuscation methods to conceal the code's true nature.
- Example: Encrypt the main body of the code and add a decryption function that decrypts the code before execution[3].
-
Dynamic Encryption Keys:
- Use different encryption keys for each new instance of the code.
- Example: Generate a random key each time the code is executed and use it to decrypt the payload[1].
-
Variable Code Structure:
- Change the code structure by rearranging subroutines or using different registers.
- Example: Rearrange the order of functions or use register swapping to alter the code's appearance[1].
-
Behavioral Adaptation:
- Alter the execution patterns to blend in with normal system processes.
- Example: Use different execution paths or timing to make the code harder to detect[1].
Here is a simplified example of a polymorphic obfuscation algorithm in Python, demonstrating some of these techniques:
import base64
import random
import string
def generate_random_key(length=16):
return ''.join(random.choice(string.ascii_letters + string.digits) for _ in range(length))
def encrypt_code(code, key):
# Simple XOR encryption for demonstration
return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(code, key * (len(code) // len(key) + 1)))
def decrypt_code(encrypted_code, key):
return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(encrypted_code, key * (len(encrypted_code) // len(key) + 1)))
# Example code to be obfuscated
code = """
def main():
print("Hello, World!")
# Other code here...
if __name__ == "__main__":
main()
"""
# Generate a random key
key = generate_random_key()
# Encrypt the code
encrypted_code = encrypt_code(code, key)
# Create the obfuscated code with a decryption function
obfuscated_code = f"""
import base64
def decrypt_code(encrypted_code, key):
return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(encrypted_code, key * (len(encrypted_code) // len(key) + 1)))
key = "{key}"
encrypted_code = "{encrypted_code}"
decrypted_code = decrypt_code(encrypted_code, key)
exec(decrypted_code)
"""
# Save the obfuscated code to a file
with open("obfuscated_code.py", "w") as f:
f.write(obfuscated_code)To change the code structure, you can rearrange functions or use different registers. Here’s an example of rearranging functions:
# Original code
code = """
def function_a():
print("Function A")
def function_b():
print("Function B")
def main():
function_a()
function_b()
if __name__ == "__main__":
main()
"""
# Rearrange the functions
functions = ["function_a", "function_b"]
random.shuffle(functions)
obfuscated_code = f"""
def {functions}():
print("Function A")
def {functions[1]}():
print("Function B")
def main():
{functions}()
{functions[1]}()
if __name__ == "__main__":
main()
"""To adapt the behavior, you can introduce random delays or different execution paths:
import random
import time
# Original code
code = """
def main():
print("Hello, World!")
# Other code here...
if __name__ == "__main__":
main()
"""
# Introduce random delays and different execution paths
obfuscated_code = f"""
import random
import time
def main():
if random.random() < 0.5:
time.sleep(random.uniform(0.1, 1.0))
print("Hello, World!")
# Other code here...
if __name__ == "__main__":
main()
"""Here is a more comprehensive example that combines these techniques:
import base64
import random
import string
import time
def generate_random_key(length=16):
return ''.join(random.choice(string.ascii_letters + string.digits) for _ in range(length))
def encrypt_code(code, key):
return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(code, key * (len(code) // len(key) + 1)))
def decrypt_code(encrypted_code, key):
return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(encrypted_code, key * (len(encrypted_code) // len(key) + 1)))
# Example code to be obfuscated
code = """
def function_a():
print("Function A")
def function_b():
print("Function B")
def main():
function_a()
function_b()
if __name__ == "__main__":
main()
"""
# Generate a random key
key = generate_random_key()
# Encrypt the code
encrypted_code = encrypt_code(code, key)
# Rearrange the functions
functions = ["function_a", "function_b"]
random.shuffle(functions)
# Create the obfuscated code with a decryption function and behavioral adaptation
obfuscated_code = f"""
import base64
import random
import time
def decrypt_code(encrypted_code, key):
return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(encrypted_code, key * (len(encrypted_code) // len(key) + 1)))
key = "{key}"
encrypted_code = "{encrypted_code}"
decrypted_code = decrypt_code(encrypted_code, key)
def {functions}():
print("Function A")
if random.random() < 0.5:
time.sleep(random.uniform(0.1, 1.0))
def {functions[1]}():
print("Function B")
if random.random() < 0.5:
time.sleep(random.uniform(0.1, 1.0))
def main():
{functions}()
{functions[1]}()
if __name__ == "__main__":
main()
"""
# Save the obfuscated code to a file
with open("obfuscated_code.py", "w") as f:
f.write(obfuscated_code)This example demonstrates basic polymorphic obfuscation techniques, including encryption, variable code structure, and behavioral adaptation. However, for real-world applications, more sophisticated methods and continuous evolution of the obfuscation techniques are necessary to evade detection by advanced security systems.