shell_exec

The shell_exec function in PHP is used to execute shell commands from a PHP script and return the complete output as a string. It's similar to the exec function but with a key difference in how the output is handled. While shell_exec provides useful functionality for running external programs, it can pose serious security risks if not used correctly.

The primary security risk with shell_exec is the potential for command injection attacks. If user-provided data is not properly sanitized, an attacker can inject and execute malicious commands on the server.

shell_exec can execute any command that the server’s shell can execute, which can lead to unauthorized system access, data leakage, or server compromise.