Drudge, other sites flooded with malicious ads

Invisible PDF file used to attack computers

Criminals flooded several online ad networks with malicious advertisements over the weekend, causing popular Web sites such as the Drudge Report, Horoscope.com and Lyrics.com to inadvertently attack their readers, a security company said Wednesday.

The trouble started on Saturday, when the criminals somehow placed the malicious ads on networks managed by Google's DoubleClick, as well as two others: YieldManager and ValueClick's Fastclick network, according to Mary Landesman, a senior security researcher with ScanSafe.

The attack comes just a week after the New York Times Web site was tricked into displaying a deceptive 'scareware' advertisement for fake antivirus software from scammers pretending to be ad buyers with Vonage, an Internet telephony company.

Instead of trying to trick Web surfers into buying bogus software, these ads attacked.

They would pop up a nearly invisible window in the victim's browser that contained a maliciously encoded pdf document, which included attack code that placed a variant of the Win32/Alureon Trojan horse program on the victim's computer. Sometimes, the ads would also try to exploit a previously patched flaw in Microsoft's DirectShow software, Landesman said.

"The user would have seen a very brief opening of a blank pdf window and it would be at the bottom portion of their screen," she said. The Alureon Trojan is known to download additional malware and often hijack victims' search results, she said.

The pdf attacks apparently only affected victims with out-of-date versions of Adobe's Reader or Acrobat software, she added.

Between Saturday and Monday, the ads accounted for 11 percent of all Web pages blocked by ScanSafe's Web filtering software, a sign that many people were being presented with the malicious ads. And because the pdf pages were modified slightly every time they were displayed, most antivirus products didn't detect them.

In tests, ScanSafe found that only 3 out of 41 antivirus vendors detected the malware.

"To be honest, they were pretty clever in the way they carried this out," Landesman said. "They managed to infiltrate sites that enjoy very good traffic and they were able to use a mechanism for creating this pdf that caused it to be nearly completely undetected."

This is not the first time Google's DoubleClick has been associated with this type of malicious advertising. Earlier this year criminals placed similar ads on the home page of technology trade magazine eWeek, whose ads were managed by DoubleClick.

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.

Robert McMillan

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.

Ada Chan

Dynabook Portégé X30L-G

I highly recommend the Dynabook Portégé® X30L-G notebook for everyday business use, it is a benchmark setting notebook of its generation in the lightweight category.

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.

Featured Content

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?