Courses / Remote Code Execution (RCE)

Shellshock (CVE-2014-6271)

Last Edit: 10-05-2024

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Shellshock (CVE-2014-6271)

Shellshock is a vulnerability in the GNU Bash shell that was widely used in Unix-based systems. The vulnerability allowed attackers to inject and execute code via environment variables.

Attack Vector

An attacker could trigger the vulnerability by manipulating the HTTP_USER_AGENT variable in HTTP requests to execute arbitrary commands on a web server.

Example Code

Below is an example of an HTTP request exploiting the Shellshock vulnerability:

GET /cgi-bin/any_script.cgi HTTP/1.1 Host: vulnerable.example.com User-Agent: () { :;}; /bin/bash -c 'echo Hello, I am executing code!'

In this example, the User-Agent

header contains a Bash function followed by a command to execute. If the web server is vulnerable, it would execute the echo command.

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Course Summary
RCE: Introduction
Free 1 pt
RCE in PHP
Pro 1 pt
Shellshock (CVE-2014-6271)
Pro 1 pt