Command Injection: Mastering Exploitation Techniques with a Comprehensive Cheatsheet

Command Injection is a powerful attack vector where an attacker manipulates vulnerable applications to execute arbitrary system commands. When developers fail to properly handle user input, attackers gain the opportunity to exploit this oversight and directly interact with the underlying operating system. For hackers, this opens up a treasure trove of possibilities — from data exfiltration to full system compromise.

Command Injection occurs when user inputs are executed as part of system-level commands without proper validation. Here’s a typical example:

In this scenario, if $USER_INPUT isn't sanitized, an attacker can inject additional commands using separators like ;, &&, or |. For instance:

This executes ping -c 4 127.0.0.1 followed by the whoami command, revealing the application's runtime user.

Here’s a collection of ready-to-use payloads for various Command Injection…