The Sophos Web Appliance Remote / Secure Web Gateway server (version 4.2.1.3) is vulnerable to a Remote Command Injection vulnerability in its web administrative interface. These vulnerabilities occur in MgrDiagnosticTools.php (/controllers/MgrDiagnosticTools.php), in the component responsible for performing diagnostic tests with the UNIX wget utility. The application doesn't properly escape the information passed in the 'url' variable before calling the executeCommand class function ($this->dtObj->executeCommand). This function calls exec() with unsanitized user input allowing for remote command injection. The page that contains the vulnerabilities, /controllers/MgrDiagnosticTools.php, is accessed by a built-in command answered by the administrative interface. The command that calls to that vulnerable page (passed in the 'section' parameter) is: 'configuration'. Exploitation of this vulnerability yields shell access to the remote machine under the 'spiderman' user account.