We briefly explained command injection as one of the top 10 web application vulnerabilities. Command injection allows an attacker to execute system commands directly from the web browser due to the lack of input valid checks on the backend or the webserver side. We used HackTheBox LoveTok challenge to fully demonstrate this subject.. This was part of HackTheBox LoveTok.

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In command injection, the attacker-injected code gets executed by the underlying OS allowing the attacker to execute system commands to discover sensitive files, navigate through the directory structure, create files and of course plant reverse shells and backdoors. In verbose command injection, the output is returned to the user where a decision can be formed if the system is vulnerable to command injection.

In the challenge, we inject the “format” parameter in the URL below


We used the below webshell to achieve command injection

${system($_GET[cmd])}&cmd=ls /

And to retrieve the flag just type

${system($_GET[cmd])}&cmd=cat /flagname

Video Walkthrough

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