By Matthew Broersma
AUGUST 23, 2005
A fresh security flaw has surfaced in the PHP Web service protocol
that could allow attackers to take control of vulnerable servers.
The bug was found in XML-RPC for PHP and PEAR XML_RPC as the result of
a security audit by the Hardened-PHP Project. The group said it
decided to carry out its own audit after other flaws were disclosed in
the two libraries earlier this summer.
The new flaw takes advantage of a technique similar to the earlier
vulnerabilities, which involved eval() statements, according to
Hardened-PHP. "To get rid of this and future eval() injection
vulnerabilities, the Hardened-PHP Project has developed, together with
the maintainers of both libraries, a fix that completely eliminates
the use of eval() from the library," Hardened-PHP said in an advisory.
XML-based Remote Procedure Call (RPC) systems, such as XML-RPC, are
used with HTTP to power Web services, a simple and increasingly
popular way of providing services online. XML-RPC for PHP (also called
PHPXMLRPC) and PEAR XML_RPC use XML-RPC as the PHP scripting language.
The bug affects a large number of Web applications, particularly
PHP-based blogging, Wiki and content management programs, according to
security experts. The PHPXMLRPC and PEAR XML_RPC libraries are used in
many popular Web applications, such as PostNuke, Drupal, b2evolution
Content-management systems and blogs are increasingly used by large
corporations as a way of interacting with customers and other members
of the public. IBM even jumped into the enterprise blogging game
Version 1.4.0 of PEAR XML_RPC fixes the problem in PEAR XML_RPC; it is
available from the PEAR Web site.
PHPXMLRPC is fixed with Version 1.2, which is available at the
PHPXMLRPC project site.
Software projects using the libraries have issued their own updates
fixing the problem; these include the PHP packages included with the
Red Hat and Ubuntu Linux distributions.
The French Security Incident Response Team, rated the flaw as
"high-risk," while independent security firm Secunia labeled it
Sept 16-18th, 2005
San Diego, California