Malvertising campaigns are becoming harder to detect

The techniques used by attackers are difficult even for security researchers to study

Jerome Segura, a senior security researcher with Malwarebytes, was recently stumped by a cyberattack he was studying. It seemed to keep vanishing.

Segura often studies malvertising, which involves seeding ad networks with harmful online advertisements that then appear on websites, potentially delivering malware to a person's computer.

It's a particularly insidious type of attack, since a person merely has to view an advertisement to become infected if their computer has a software vulnerability. 

"We knew there was something different that malvertisers were doing," said Segura in a phone interview Thursday.

The problem was they couldn't replicate the attack by viewing the malicious ad. It's almost as if the attackers knew they were being watched.

Cyberattackers often profile machines -- known as fingerprinting -- in order to attack ones that are being used by security researchers. Machines on certain IP addresses or VPN networks or those running virtual machines won't be attacked.

Segura couldn't get another look at the attack until he went home and used his home computer rather than the ones in Malwarebytes' lab.

The suspicious advertisement contained a one-by-one pixel GIF image. That's not usual, as pixels are used for tracking purposes, but this one actually contained JavaScript.

The JavaScript exploits an information leakage vulnerability (CVE-2013-7331) in older unpatched versions of Internet Explorer, Segura said. The vulnerability can be used to parse a computer's file system and figure out if it's running certain AV programs.

If a computer checked out, its user was redirected by the advertisement to a server running the Angler exploit kit, Segura said.

It is not unusual for cyberattackers to do some quick reconnaissance on potential victims. But Segura said this time around, the attackers are also taking other steps that make it very difficult for ad networks and security researchers to detect bad behavior.

The malicious ad, including the one-by-one pixel, was also delivered over SSL/TLS, which makes it harder to detect potentially malicious behavior, Segura said.

The malicious ad was carried by Google's DoubleClick and dozens of other ad networks. It appears the attackers had set up fake domains and even LinkedIn profiles months before to appear they were legitimate before supplying their malicious advertisement to the online advertising companies.

"It shows you how deceptive they can be and how many fake advertisers are out there," he said.

Segura said he has been in touch with DoubleClick and other online advertising companies, but the malvertising ad is still running in some places.

The automated nature of online advertising and the labyrinth of relationships between companies has made filtering malicious ads difficult, he said.

"What criminals have figured out is it's easier to infiltrate a third partner that works with Google but doesn't necessarily have the same security screening and tight guidelines," Segura said.

Malwarebytes posted a writeup of its research on its blog.

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.

Jeremy Kirk

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

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

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

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?