Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.


05:00 PM
Connect Directly

Malvertising Campaign Rages Undetected For 3 Weeks

Instead of injecting nasty code into ads, attackers pose as legitimate advertisers and manipulate ad networks' chain of trust.

Although malvertising campaigns are usually detected after a few days, a widespread malvertising campaign that abused several major ad networks evaded detection for three weeks, according to researchers at Malwarebytes.

"We saw there was activity," says Malwarebytes senior security researcher Jerome Segura. "We saw there was something going on, but we just couldn't pinpoint it."

Segura believes the attackers behind this attack campaign are the same ones behind previous attacks his team has reported on, but they've developed a number of new tactics to make themselves harder to track down. 

First, the malvertisers went to great lengths to make themselves look like legitimate businesses using real-time bidding. They used domain names that had been registered years ago, some of which were even listed with the Better Business Bureau. The ads they submitted appeared to be created by professional designers.  

Second, "the ads themselves were perfectly clean," says Segura. Instead of injecting malicious code directly into the ads, the ads just redirected victims to someplace that would download malicious code (in this case, the Angler exploit kit).

"At the end of the day, it's a break in the chain of trust between ad networks and advertisers," says Segura.

He explains that in order to let advertisers maintain control over their content, the ads were served up from the advertiser's (in this case, malvertiser's) own server, and through an encrypted HTTPS channel. Segura says this system, of letting a third party directly serve up content and encrypt that communication so that it cannot be inspected to see if the content is malicious, is "a big security blunder." 

"A fraudulent ad server using HTTPS. We were basically blind to it," he says.

Another new method the malvertisers used: in earlier attacks, they'd used Google URL shortener in their redirects -- a problem Malwarebytes and Google were working to solve, Segura says. In this new campaign, the attackers started with Google, and then shifted to a custom URL shortener running from their own server.

"The degree of complexity, combined with the effort to create these fake personas is the next stage of malvertising attacks," says Segura.

Using these methods, attackers compromised a variety of small ad networks and major ad networks, including DoubleClick, AppNexus, and ExoClick. Through those networks, they hit a variety of major media sites (including ebay.co.uk, drudgereport.com, and answers.com) and adult sites (including nuvid.com, upornia.com, and eroprofile.com) -- all with tens of millions of visitors per month, giving the malvertisers an opportunity to cast a wide net.

"Publishers are really the victims here," says Segura, "but ad networks, this affects their reputation."

Segura reminds users that ads are just the vehicle for exploits, so instead of relying on ad blockers, keep their systems updated and install all their other exploit mitigation tools.

As for the ad networks like DoubleClick, it's about "being very careful where the ad content is served from," says Segura. He points out that even the financial model of these companies is problematic -- allowing very low-cost introductory packages gives attackers the opportunity to launch short campaigns with small investments. He suggests they consider making the barrier to entry higher to keep the bad guys out. "They owe this to their customers."

Sara Peters is Senior Editor at Dark Reading and formerly the editor-in-chief of Enterprise Efficiency. Prior that she was senior editor for the Computer Security Institute, writing and speaking about virtualization, identity management, cybersecurity law, and a myriad ... View Full Bio

Recommended Reading:

Comment  | 
Print  | 
More Insights
Newest First  |  Oldest First  |  Threaded View
User Rank: Strategist
9/15/2015 | 8:11:30 AM
Who is the customer?
"They owe this to their customers" I presume that this is intended to mean that the readers (clickers) are the customers. Nothing could be further from the truth. Customers pay. In the case of Internet sites supported by advertising, you, the reader, are the product. Or as someone smarter than I has said, "if it is free, you are the product." This is where the disconnect occurs with the malware problem in advertising. The advertising companies are not attached to the problem. They only peripherally feel the pain. The user, at home or in a business the IT shop, feels the pain, but rarely has any idea which company brokered the ad that delivered the malware. It works for the, criminals doing this, because it is safe. It works for the add brokers because it is safe. It doesn't work for us, at home or in the office, because WE ARE THE PRODUCT. Will top of the line companies like Doubleckick learn and adjust? Of course. Will other ad brokers? Some will not. We definately neeed to thank the guys at MalwareBytes that had the perserverance and brains to work this out. They done good!
Ransomware Is Not the Problem
Adam Shostack, Consultant, Entrepreneur, Technologist, Game Designer,  6/9/2021
How Can I Test the Security of My Home-Office Employees' Routers?
John Bock, Senior Research Scientist,  6/7/2021
New Ransomware Group Claiming Connection to REvil Gang Surfaces
Jai Vijayan, Contributing Writer,  6/10/2021
Register for Dark Reading Newsletters
White Papers
Current Issue
The State of Cybersecurity Incident Response
In this report learn how enterprises are building their incident response teams and processes, how they research potential compromises, how they respond to new breaches, and what tools and processes they use to remediate problems and improve their cyber defenses for the future.
Flash Poll
How Enterprises are Developing Secure Applications
How Enterprises are Developing Secure Applications
Recent breaches of third-party apps are driving many organizations to think harder about the security of their off-the-shelf software as they continue to move left in secure software development practices.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
PUBLISHED: 2021-06-21
neos/forms is an open source framework to build web forms. By crafting a special `GET` request containing a valid form state, a form can be submitted without invoking any validators. Form state is secured with an HMAC that is still verified. That means that this issue can only be exploited if Form F...
PUBLISHED: 2021-06-21
Textpattern 4.7.3 contains an aribtrary file load via the file_insert function in include/txp_file.php.
PUBLISHED: 2021-06-21
Cross Site Scriptiong vulnerability in Typesetter 5.1 via the !1) className and !2) Description fields in index.php/Admin/Classes,
PUBLISHED: 2021-06-21
mongo-express is a web-based MongoDB admin interface, written with Node.js and express. 1: As mentioned in this issue: https://github.com/mongo-express/mongo-express/issues/577, when the content of a cell grows larger than supported size, clicking on a row will show full document unescaped, however ...
PUBLISHED: 2021-06-21
In memory management driver, there is a possible memory corruption due to a race condition. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android SoCAndroid ID: A-185196177