Dangerous PHP Functions Command Execution exec - Returns last line of commands output passthru - Passes commands output directly to the browser system - Passes commands output directly to the browser and returns last line shell_exec - Returns commands output \`\` (backticks) - Same as shell_exec() popen - Opens read or write pipe to process of a command proc_open - Similar to popen() but greater degree of control pcntl_exec - Executes a program PHP Code Execution Apart from eval there are other ways to execute PHP code: include/require can be used for remote code execution in the form of Local File Include and Remote File Include vulnerabilities.