Generating Undetectable Payloads with Bashfuscator and DOSfuscation

Manual obfuscation is a craft. But when you are up against a WAF that has seen every quote-insertion and base64 trick in public writeups, you need payloads that have literally never existed before. Bashfuscator generates structurally unique obfuscated commands using randomized mutation chains. No two outputs are the same. No static signature can match them.

Installing Bashfuscator

Generating a controlled payload

Running Bashfuscator with just -c produces a random mutation chain that can output anywhere from 200 characters to over a million. You do not want that. Use the size and layer flags to constrain the output to something manageable.

The output is 104 characters. It uses array indexing and a for loop to reconstruct the command character by character. No substring of the output matches cat, /etc, or passwd. A signature-based WAF has nothing to match against.

Verifying the payload executes correctly

It works. The obfuscated mess resolves to cat /etc/passwd at runtime. Before using this in an injection, audit the payload for filtered characters. If it contains spaces, replace them. If it contains slashes, use the environment variable extraction technique from lesson nine.

Windows: DOSfuscation for CMD and PowerShell

DOSfuscation is the Windows equivalent. It is an interactive PowerShell module that generates obfuscated commands using environment variable substring extraction, encoding, and binary syntax tricks.

The output reconstructs the command using substring slices of environment variables like %TEMP%, %SystemRoot%, and %ALLUSERSPROFILE%. No literal file path appears in the payload. CMD reassembles it at execution time.

You now have the full offensive toolkit: detection, operator injection, filter bypass, manual obfuscation, and automated payload generation. The next module flips the perspective. You are the developer. You are the defender. And you need to make sure none of the techniques you just learned work against your application.