The Santy worm uses a flaw in the widely used community forum software known as the PHP Bulletin Board (phpBB) to spread, according to updated analyses. The worm searches Google for sites using a vulnerable version of the software, antivirus firm Kaspersky said in a statement.
Almost 40,000 sites may have already been infected. Using Microsoft's Search engine to scan for the phrase "NeverEverNoSanity"--part of the defacement text that the Santy worm uses to replace files on infected Web sites--returns nearly 39,000 hits.
"Santy.a is spreading rapidly," antivirus firm Kaspersky stated in a new release published Tuesday. "However, this does not directly affect users. Although the worm infects Web sites, it does not infect computers used to view those sites."
The worm sends Google a specific search request, essentially asking for a list of vulnerable sites. Armed with the list, the worm then attempts to spread to those sites using a PHP request designed to exploit the phpBB bulletin board software.
The worm is the latest twist on using Google as an attack tool, a practice known asA search of Google for the phrase "Powered by phpBB"--an acknowledgment appended to the bottom of any site that uses the software--returned 6 million hits, an indication of the popularity of phpBB. The actual number of sites is likely much lower, since the acknowledgement is appended to multiple pages on a single bulletin board site. . It may also be the first time a program used Google to identify victims for an attack.
"There are tons of these PHP bulletin board installs around," said Johannes Ullrich, chief technology officer of the Internet Storm Center, which tracks online threats. Initial analyses by the ISC had concluded that the flaw exploited by the worm occured in the software that interprets Web pages written scripting language PHP: Hypertext Preprocessor (PHP). That flaw was.
Using Google to determine vulnerable sites is not an academic exercise. The worm does exactly that: Once Santy infects a Web site, it searches Google for other sites running phpBB and then attempts to infect those sites as well.
After it has taken over a site, the worm deletes all HTML, PHP, active server pages (ASP), Java server pages (JSP), and secure HTML pages, and replaces them with the text, "This site is defaced!!! This site is defaced!!! NeverEverNoSanity WebWorm generation X," according to Kaspersky. For "X," the worm inserts a number representing how far the current instance of the program is descended from the original worm release. MSN searches have found 24th generations of the worm.
Google did not immediately comment on the worm, but a spokesman did say that the company had seen the information and had started to study the issue.
The response, or lack thereof, frustrated some members of the antivirus community, who believed that the search giant could easily stop the worm by filtering out its search for victims.
"We know exactly which searches to stop," said Mikko Hypponen, research director of antivirus firm F-Secure. "It would be trivial to stop this thing."
Web sites using a vulnerable version of phpBB should upgrade, the phpBB Project site advises.