Waledac botnet poised for a rebound with stolen credentials

Analysts with Last Line say the botnet has a collected a trove of high-quality e-mail accounts for spam

The Waledac botnet, crippled by legal action from Microsoft and covert infiltration by security researchers just a year ago, appears poised for a big comeback.

Waledac was mostly shut down after Microsoft -- whose Hotmail service had been abused by the botnet -- was granted a temporary restraining order by a U.S. court that shut down domain names the botnet used to communicate. Security researchers also managed to disrupt Waledac's peer-to-peer communications system and gain control over some 60,000 infected computers.

But according to researchers from security vendor Last Line, Waledac has collected 489,528 credentials for POP3 e-mail accounts, which will likely be used for high-quality spam campaigns.

"The technique abuses legitimate mail servers by authenticating as the victim through the SMTP-AUTH protocol to send spam messages," according to Last Line's blog. "This method makes IP-based blacklist filtering considerably more difficult."

Additionally, Waledac has also collected 123,920 log-in credentials for FTP servers.

"This number is significant considering the Waledac controllers use an automated program to login to these servers and patch (or upload) specific files to redirect users to sites that serve malware or promote cheap pharmaceuticals," Last Line said. "In January, we observed 222 websites that had been compromised containing a total of 9,447 pages."

Other data from Last Line's analysis of a Waledac command-and-control server showed that more than 12,000 infected computers had connected. That figure is far fewer than estimates of Waledac before the February 2010 takedown, but could rise.

"The Waledac botnet remains just a shadow of its former self for now, but that's likely to change given the number of compromised accounts that the Waledac crew possesses," Last Line said.

Waledac showed signs of a resurgence around the end last year, when researchers from Websense noticed a large run of spam purporting to be electronic greeting cards. The messages contained links that if clicked redirected to a domain that falsely informed victims they needed to upgrade Flash player to see the card. The supposed Flash update file is malicious.

The Shadowserver Foundation, which tracks botnets, wrote at the end of December that the latest version of Waledac was also using fast-flux, a technique that allows the domain to be hosted on a rotating selection of IP addresses, for hosting malicious domains.

Send news tips and comments to jeremy_kirk@idg.com

Join the PC World newsletter!

Error: Please check your email address.

Tags securityLast Linedata protectionExploits / vulnerabilitiesmalware

Struggling for Christmas presents this year? Check out our Christmas Gift Guide for some top tech suggestions and more.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jeremy Kirk

IDG News Service

Most Popular Reviews

Follow Us

Best Deals on GoodGearGuide

Shopping.com

Latest News Articles

Resources

GGG Evaluation Team

Kathy Cassidy

STYLISTIC Q702

First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni

STYLISTIC Q572

For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell

LIFEBOOK UH574

The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi

STYLISTIC Q702

The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott

STYLISTIC Q702

My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.

Latest Jobs

Shopping.com

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?