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 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.

Jeremy Kirk

IDG News Service
Show Comments

Brand Post

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?