Avoid executing shell commands with arbitrary input

Documentos > Code Analysis > Static Analysis Rules > Avoid executing shell commands with arbitrary input

This page is not yet available in Spanish. We are working on its translation.
If you have any questions or feedback about our current translation project, feel free to reach out to us!

Metadata

ID: php-security/avoid-backticks

Language: PHP

Severity: Error

Category: Security

CWE: 94

Description

When you execute shell commands with user-defined inputs in PHP, it leaves your application open to shell injection attacks. In these attacks, a malicious user can manipulate the input to execute arbitrary shell commands, which can lead to unauthorized access, data leakage, or even system compromise.

To ensure the safety of your application, it’s important to avoid using user-defined input directly in shell commands. Instead, use built-in PHP functions that can perform the required task without the need for executing shell commands. If there’s a need to use shell commands, make sure to sanitize and validate the user input thoroughly before using it.

Non-Compliant Code Examples

<?php
echo `ping -n 3 {$user_input}`;

Compliant Code Examples

<?php
echo `ping -n 3 domain.tld`;