Drive-by download attack mows down thousands of websites

Miscreants are exploiting website vulnerabilities to booby-trap thousands of legitimate sites.

The mass attack, thought to be the work of hackers based in China, hit between 2,000 and 10,000 Western servers at the end of last week alone, Russian net security firm Kaspersky Labs reports. Most of the hacked sites run Microsoft ASP technology and are thought to have been hit either using SQL injection attacks or using stolen site admin login credentials.

SQL injection attacks against vulnerable webservers have become a frequent tactic in malware distribution over the last two to three years. The latest assault is smaller in scale than previous attacks, some of which has claimed over a million sites. But it is still noteworthy, not least because of concerns it may get bigger.

Kaspersky reports that the crackers are adding a JavaScript tag to the html of hacked sites. This causes surfers visiting the site to pull content from one of six gateway sites, which redirect to a server hosting malware located in China.

A range of exploits are hosted on this site designed to take advantage of recently patched flaws in IE, Macromedia Flash Player, Microsoft's notoriously wobbly ActiveX technology, and (unusually) Firefox.

These various vulnerabilities are in turn being used to push Trojan downloader code onto the PCs of surfers who stray onto compromised websites. The end goal of the attack is to load backdoor code onto Windows Pcs in order to steal World of Warcraft login credentials or to plant other forms of spyware and Trojans.

As with previous, similar drive-by download-style attacks the compromise sites are typically legitimate mainstream sites. So staying away from smut and warez is not enough to avoid harm. Keeping up to date with patches is the best defence. Users should update their applications as well as keep up to date with Microsoft's security releases. Tools such as Secunia's Software Inspector can help with this irksome task. ®