More than 10,000 websites have been infected by a sophisticated and fast-acting Trojan downloader that attempts to install malware on visiting PCs. At least one security firm, Trend Micro, is working with the FBI to contain the damage and track down the perpetrators.
The attack is noteworthy for the number of sites it has managed to infect in a relatively short period of time. Between Friday and Sunday night, the number jumped from 1,100 to about 2,500. By Monday afternoon, California time, there were more than 10,000 infected sites, according to Paul Ferguson, a network architect for Trend Micro.
Once a server is infected, attackers embed an invisible iframe into the web page that silently redirects visitors to a pair of other sites that attempt to use previously patched Windows vulnerabilities to install malicious keylogging software. The redirected sites use an attack kit known as MPack, which according to this writeup from Symantec is "a professionally written collection of PHP software components designed to be hosted and run from a PHP server with a database backend."
Researchers are still trying to figure out how the attackers have managed to infect the servers.
"It's all over the map," Ferguson says. "The sheer numbers right now are keeping us pretty busy."
While most of the sites are hosted in Italy, researchers have found few common denominators that might suggest how the attackers are able to compromise the machines. It's unclear if attackers are exploiting vulnerabilities on the servers themselves or hacking into service provider infrastructure. Ferguson speculates the attackers are using an automated tool similar to metasploit to search for sites that are vulnerable.
The hacked websites cover the gamut, from a site connected to the rock musician Bon Jovi to one that tries to raise money for charity work of the late Mother Teresa. Most of the compromised sites are mom-and-pop run affairs and are concerned with travel or entertainment.
An iframe buried underneath the hacked sites redirects users to a server that's hosted at a San Francisco-area co-location site that's been used previously by cyber criminals, Ferguson says. That site redirects to yet another server hosted in Chicago. The San Francisco server is registered to a front-company based in Hong Kong. Ferguson said researchers and authorities are trying to contain the attacks by getting the San Francisco and Chicago sites shut down.
MPack is a powerful kit that bundles together many different malware tools. Among other things, it logs detailed information about the machines it attacks, including the IP addresses of machines it has infected and what exploits a particular user is vulnerable to. It is similar to another malkit called WebAttacker.
The attack resembles one from February which targeted certain Miami Dolphins Web sites on the same day the National Football League team hosted the Super Bowl. The legions of fans who visited the site were redirected to third party sites that attempted to install malware on their machines.
Says Ferguson: "All this Web 2.0 stuff is going to turn in to Web uh oh!" ®