A penetration tester obtains a reverse shell on a server and executes the following command...

The command appends PHP code to a web-accessible file, effectively creating a simple web shell. By adding system($_GET[ " c " ]); into index.php, the tester can later execute operating system commands remotely through the web server by passing a parameter in the URL. This is most closely associated with establishing persistence, because it gives the tester a reusable method to regain command execution even if the original reverse shell session is lost. It is not primarily lateral movement, since the action is being performed on the already compromised host rather than expanding to another system. It is also not mainly about avoiding detection or bypassing a specific security control. The key objective is maintaining durable access through an alternate remote execution channel.

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