Net-Worm.Perl.Santy.a Exploits a Vulnerability in phpBB

Kaspersky Lab, a leading manufacturer of secure content management systems, has detected a new worm, Net-Worm.Perl.Santy.a. This worm infects certain web sites by exploiting a vulnerability in phpBB, a popular package used to create Internet forums. Santy.a is spreading rapidly, and has caused an epidemic. However, this does not directly affect end users – although the worm infects web sites, it does not infect computers used to view these sites.

Santy.a is something of a novelty – it creates a specially formulated Google search request, which results in a list of sites running vulnerable versions of phpBB. It then sends a request containing a procedure which will trigger the vulnerability to these sites. Once the attacked server processes the request, the worm will penetrate the site, gaining control over the resource. It then repeats this routine.

Once the worm has gained control over a site, it will scan all directories on the infected site. All files with the extensions .htm, .php, .asp, .shtm, .jsp and phtm will be overwritten with the text ‘This site is defaced!!! This site is defaced!!! NeverEverNoSanity WebWorm generation’.

Apart from defacing infected sites with this text, the worm has no payload. It will not infect machines which are used to view infected sites. Kaspersky Lab recommends that all users of phpBB should upgrade to version 2.0.11 to prevent their sites from being defaced.

An urgent update to Kaspersky Anti-Virus databases has already been issued. Information about Santy.a can be found in the Kaspersky Virus Encyclopaedia.