PHP holes leave Web servers open to attack

Hackers could exploit vulnerabilities in the open source scripting language PHP to execute arbitrary code on Web servers running PHP, security experts said on Wednesday.

PHP is a server-side scripting language often used by Web programmers to dynamically create HTML pages.

Vulnerabilities in code used to upload files to the server from a user's PC via a Web page could allow an intruder to execute arbitrary code with the privileges of the PHP process or to interrupt normal operations of the Web server, the Computer Emergency Response Team (CERT) said in an advisory. PHP can be installed on Web servers such as Apache, IIS, Caudium, iPlanet and OmniHTTPd, CERT said.

According to a warning posted by Stefan Esser of the German Web-design and security company e-matters, he and his team found several flaws in the "php_mime_split" function used by PHP to handle multipart/form-data POST requests.

CERT recommends that users upgrade to the newest version, PHP 4.1.2, or apply patches to older versions.

PHP is an open source project of the Apache Software Foundation, which also issued a warning and patches for the software at its PHP support site.

PHP is included with many distributions of the Linux open-source operating system. Linux developers Red Hat and MandrakeSoft have been made aware of the holes in PHP and are working to eradicate the problems as well as offer patches for their customers, CERT said.

The IDG News Service is a Network World affiliate.