Fraudsters have set up a fake site featuring a backdoored version of the WordPress blogging application as part of a sophisticated malware-based attack.
The fake Wordpresz.org site offered up what purports to be version 2.6.4 of the open source blogging tool. In reality all but one of the files are identical to the latest pukka (2.6.3) version of WordPress.
The crucial difference comes in the form of a Trojanised version of pluggable.php, according to Sophos virus researcher Paul Baccas. Sophos detects the malicious code as WPHack-A Trojan.
"The new PHP contains call backs to the Fake WordPress site and looks to be stealing credentials," Baccas reports.
The issue came to light via a posting by blogger Craig Murphy who reports that he received a "High Risk Vulnerability Warning" from the spoofed WordPress domain when he logged into his admin account.
Peter Westwood, one of WordPress's lead developers, responded promptly to our requests for comment on the attack, which he reckons relies on exploiting older (vulnerable) code.
It looks like sites which have not upgraded to 2.6.3 are being exploited in an interesting way whereby a hacker, probably using an automated script, is hacking into sites with the vulnerability and changing the settings of one of the dashboard modules to point to a different feed thereby encouraging people to go to a different site which is offering a dodgy upgrade.
"We recommend that people upgrade as soon as possible when we release a security release so as to ensure they are not vulnerable to issues which will likely have exploits in the wild.
Also in the upcoming 2.7 release of WordPress we are including a built-in upgrade mechanism within WordPress which will allow people to upgrade automatically with ease. I would however stress the need with any piece of software to check that an upgrade is real by visiting the website of the software provider manually rather than relying on a link that you have been provided. Otherwise, as with bank phishing scams there is the potential for someone to trick you into doing something you didn't want to do.
The fake site attack represents a rare but not unprecedented attack on users of the open source blogging package.
Backdoored code on a fake site is one thing, but a vulnerability on one of the project webservers allowed hackers to upload a backdoored version of WordPress 2.1.1 in March 2007. WordPress responded to the attack by purging its servers and urging users to upgrade to version 2.1.2 of the software as explained in an advisory here.
Two months prior to this, in January 2007, many blogs were attacked using a WordPress exploit current at the time. Users often run sites using older versions of the blogging software, if a survey from last year is anything to go on.
Chris Wysopal, CTO of application security tools firm Veracode, recently told us that applying 'traditional' backdoor techniques in web 2.0 applications such as Wordpress and Content Management Software required less skills than attacking traditional software distributions. "It's the Software as a Service version of a backdoor," he said.
"Planting backdoor code is a lot easier to do with web apps. It's much harder to break into a source code repository than it is modify PHP or scripted components in a Web 2.0 application, especially when developers don't know what's in the code half the time."
The latest version of WordPress (version 2.6.3), published on 23 October, is available through Wordpress.org. ®