Time Warner Telecom may be next Sobig.F target

Romanian researchers claim to have discovered a variant of the Sobig.F virus that looks to mail and domain name servers at Time Warner Telecomfor information about how to modify its behavior.

The first Sobig.F virus contained an encrypted list of the IP (Internet Protocol) addresses of 20 servers. At a predetermined time it would contact each server in turn until one responded with the URL (Uniform Resource Locator) of a file it would then attempt to download and execute.

Last week, antivirus software developers and network operators raced to identify and shut down the 20 servers, before the machines could issue instructions to the virus. Now it seems the goalposts may have been moved, as a variant of the virus, containing a different list of servers to contact, is circulating.

The new Sobig.F variant contains an encrypted list of the names of seven servers operated by Time Warner Telecom (TWT), according to researchers at Softwin SRL, an antivirus software company in Bucharest, Romania.

Two of the servers are SMTP (Simple Mail Transfer Protocol) servers that the virus uses to send out more copies of itself in infected e-mail messages, according to Mihai Chiriac, who works on Softwin's BitDefender antivirus software. The virus tries to contact the other five -- apparently domain name servers -- on port 8998 to ask for the URL of a file to download and execute.

"When the virus tried to access the servers on that particular port, the servers did not respond because that port was closed. But this may mean that some time from now, that port may be opened. We have to look at every possibility," Chiriac said.

Chiriac found the decrypted domain names stored in his computer's memory while he was analyzing the behavior of the Sobig.F virus. Softwin has received at least three messages containing the variant, which had apparently been sent to the company randomly by the virus, and not deliberately by a human being, he said. He has not yet determined what triggers the virus to contact the TWT servers.

A TWT spokesman was not immediately able to comment on the matter.

Staff at another antivirus software company, MessageLabs Ltd. of Gloucester, England, had not yet encountered the variant, but found it intriguing that the virus might update itself using a list of domain names, rather than a list of IP addresses.

"It's interesting because it means they can update the addresses externally by manipulating the DNS," said MessageLabs Chief Information Security Analyst Paul Wood.

In this way, the target of the virus can be changed without the virus itself needing to be updated, he said.

According to BitDefender's Chiriac, the variant Sobig.F is detected by antivirus software in the same way as the original Sobig.F, only the data segment of the virus is different, he said.

Join the PC World newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

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

Peter Sayer

IDG News Service
Show Comments

Essentials

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

HD Pan/Tilt Wi-Fi Camera with Night Vision NC450

Learn more >

Lexar® Professional 1800x microSDHC™/microSDXC™ UHS-II cards 

Learn more >

Budget

Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre x360

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga 910

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

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.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?