World's most sophisticated Trojan uncovered

SecureWorks explains the SpamThru trojan

Security experts have discovered new spambot software that installs its own antivirus scanner to eliminate competition, alongside a number of other sophisticated features.

SecureWorks has described the Trojan, which it calls SpamThru, in detail. Others vendors have come up with different names for the software. One of the signs of its sophistication though is that few antivirus scanners are aware of it, SecureWorks said.

"SpamThru is a money-making operation, and the author takes great care to make sure that detection by the major vendors is avoided by frequently updating the code," said SecureWorks' Joe Stewart in the company's analysis.

SpamThru is a Trojan that turns a system into part of a network of bots designed to send out spam, a type of operation that's been around for several years. While the Trojan's network doesn't seem especially large so far - at a couple of thousand of bots - SpamThru shows that criminals are now able to treat spam software development just like any other commercial development endeavor, Stewart said.

"The complexity and scope of the project rivals some commercial software," he wrote. "Clearly the spammers have made quite an investment in infrastructure in order to maintain their level of income." The company has come across previous Trojans that attempt to switch off other malware, in order to maximize system resources, but SpamThru installs a pirated version of Kaspersky AntiVirus for WinGate, customized to skip files known to be part of SpamThru itself, naturally.

"It patches the license signature check in-memory in the Kaspersky DLL in order to avoid having Kaspersky refuse to run due to an invalid or expired license," Stewart wrote. It uses a custom peer-to-peer protocol to control communication with the network, which makes the bot network harder to kill. "Control is still maintained by a central server, but in case the control server is shut down, the spammer can update the rest of the peers with the location of a new control server, as long as he/she controls at least one peer," Stewart wrote.

Each client has its own spam engine, creating spam from a template that's transmitted using AES encryption to avoid giving access to competing spammers, SecureWorks 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.

Matthew Broersma

Techworld.com
Show Comments

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

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.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?