Hundreds of hacked domain name accounts registered through GoDaddy are being used as part of a highly effective campaign using the Angler exploit kit to infect computers with malware.
The attackers are using the accounts to create subdomains that shuttle Web surfers to websites hosting Angler, wrote Nick Biasini, an outreach engineer with Cisco Systems.
The owners of the accounts are usually unaware of the activity, which Cisco calls "domain shadowing," since they may rarely log into their accounts. Hundreds of GoDaddy accounts that have several thousand domain names assigned to them have been compromised, Biasini wrote.
At least 10,000 unique subdomains that have been created on those accounts have been used for Angler-related attacks. GoDaddy officials couldn't immediately be reached for comment.
Nearly a third of the domain names on the Internet are registered through GoDaddy, which may be why so many of the compromised accounts are with that registrar, Biasini wrote. The domain name accounts are likely compromised by stealing the login credentials through phishing attacks.
An Angler attack starts when someone views a malicious advertisement. That advertisement then redirects the person to one of the hacked subdomains, which either delivers the exploit kit or redirects to another website hosting the kit.
Cybercriminals have moved to domain shadowing to keep their malware campaigns alive for longer, Biasini wrote. In the past, cybercriminals have registered new domain names that were used for attacks, but those were often quickly blocked.
Domain shadowing is harder to stop. Biasini wrote that the hacked domain name accounts are largely random, so it's hard to predict which ones might be used next in attacks. Blocking is difficult since the cybercriminals can frequently switch to newly generated subdomains, he wrote.
"Some of the subdomains are only active for a matter of minutes and only are reached a couple of times," Biasini wrote.
That has also made it harder for researchers to get a sample of Angler to see what software vulnerabilities it is exploiting.
Angler has proved to be a very effective exploit kit, as its developers quickly incorporate the latest zero-day vulnerabilities in Adobe Systems' software such as Flash and Microsoft's Silverlight multimedia program.
Sign up for CIO Asia eNewsletters.