Shell Execution

These functions allow shell commands to be run on the server.

• backtick operator
• shell_exec
• system
• passthru
• popen
• proc_open
• pcntl_exec

These functions help with escaping input for shell execution;

• escape_shell_arg
• escape_shell_cmd

Command Injection Attack

This function list is probably incomplete. See A Catalog of Security Sensitive PHP Functions and Web Application Security