Trojan lurks, waiting to steal admin passwords

The Coreflood Trojan program has used a Microsoft administration tool to infect corporate networks

Writers of a password-stealing Trojan horse program have found that a little patience can lead to a lot of infections.

They have managed to infect hundreds of thousands of computers -- including more than 14,000 within one unnamed global hotel chain -- by waiting for system administrators to log onto infected PCs and then using a Microsoft administration tool to spread their malicious software throughout the network.

The criminals behind the Coreflood Trojan are using the software to steal banking and brokerage account usernames and passwords. They've amassed a 50G-byte database of this information from the machines they've infected, according to Joe Stewart, director of malware research with security vendor SecureWorks.

"They've been able to spread throughout entire enterprises," he said. "That's something you rarely see these days."

Since Microsoft shipped its Windows XP Service Pack 2 software with its locked-down security features, hackers have had a hard time finding ways to spread malicious software throughout corporate networks. Widespread worm or virus outbreaks soon dropped off after the software's August 2004 release.

But the Coreflood hackers have been successful, thanks in part to a Microsoft program called PsExec, which was written to help system administrators run legitimate software on computers across their networks.

For a widespread infection, attackers must first compromise a system on the network by tricking the user into downloading their program. Then, when a system administrator logs onto that desktop machine -- to perform routine maintenance, for example -- the malicious software tries to run PsExec and install malware on all other systems on the network.

Often the technique succeeds.

Over the past 16 months, Coreflood's authors have infected more than 378,000 computers. SecureWorks has counted thousands of infections in university networks and has found financial companies, hospitals, law firms, and even a U.S. state police agency that have had hundreds of infections. "It's kind of insane how often they are getting on hundreds or thousands of computers at a single company," Stewart said. "They've probably stolen far more accounts than they can use."

The SANS Internet Storm Center reported one of the infections, which affected 600 machines on a 3,000 PC network, on June 25.

Malicious programs have used PsExec for more than five years, said the software's creator, Mark Russinovich, a Microsoft technical fellow. However, this is the first time he had heard of it being used in this fashion. "PsExec doesn't expose anything that a malware author can't code themselves or even accomplish with alternate mechanisms," he said in an e-mail interview. "Once you have credentials that give you local admin rights via remote access, you own that system."

Coreflood, which is also known as the AFcore Trojan, has been around for about six years. It has been used in the past for such things as launching denial-of-service attacks, but not to steal passwords, Stewart said.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Robert McMillan

Computerworld
Show Comments

Brand Post

Shining a light on creativity

MSI has long pushed the boundaries of invention with its ever-evolving range of laptops but it has now pulled off a world first with the new MSI Creative 17.

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?