** DISPUTED **  The mod_php module for the Apache HTTP Server allows local users with write access to PHP scripts to send signals to the server's process group and use the server's file descriptors, as demonstrated by sending a STOP signal, then intercepting incoming connections on the server's TCP port.  NOTE: the PHP developer has disputed this vulnerability, saying "The opened file descriptors are opened by Apache. It is the job of Apache to protect them ... Not a bug in PHP."