Don’t Trust Online Ads! The Newly Discovered Use of Zeus
May 18th, 2011That ad that is displayed on the header of webpage you are viewing; you weren’t supposed to see that… The website owner had a very special ad in mind for you, based in part on the articles you read on the site. But that doesn’t matter, you see your computer was infect by Zeus and is part of a botnet, a network of computers that serve as robots to a botmaster.
One of the unique aspects of Zeus that few if anyone recognized in the past is that Zeus will block ads from being displayed on certain sites and will instead serve you an ad the botmaster wants you to see. Those ads can include malware to increase the botnet size, phishing schemes or simply ads the botmaster gets paid to deliver.
The cool, scary, freaky (you pick the adjective) part is that the website has no clue what ad the user is seeing but when a user gets infected, they blame the infection on the site. (I.e. I was on MSNBC.com and my computer got infected with a virus resulting in the loss of a MSNBC user)
Over the last year the biggest name in botnets has been Zeus. The software package created by an unknown hacker was created to take over computer systems, steal their user’s data, and grow a network of zombie “bot” computers waiting to be instructed on task to do next.
Security firm after security firm have been trying to reverse engineer Zeus to see exactly how it does what it does in the hopes of building a tool to block or remove it from systems.
It has been a struggle but recently things changed…
Just last week the full source code for Zeus was made available for free download on the cyber underground. And now those security firms can truly dissect how Zeus works.
A lot of time and energy will be spent at looking into how Zeus compromises a computer, how it circumvents the anti-viral and/or security software and how to stop it.
Fixes will be released in the coming weeks if not days and though these fixes will address some pieces of the code, they will likely fall short of full protection because every criminal who has been using the software has been modifying it to their tastes but I digress.
Honestly, I’m not smart enough to truly understand how the computers are taken over. In that regard I am very similar to those criminals using the software… We don’t really care how it does it rather we care how we can make money by using it.
To that end, the fact that Zeus controls the ads infected users sees has a very big “wow” factor.
When it comes to cybercrime and botnet discussions, most is focused around the theft of a user’s username and password for bank records, credit cards and financial institutions. These are big money makers that are easy to understand. Meaning we all understand that someone steals your “credentials” then impersonates you online to make purchases or wire transfer money or even apply for loans.
What are rarely focused on are the other schemes that involve your friends, your online habits and other uses of the data.
When the creator of Zeus included the ability to substitute the advertisement users saw on certain websites, he/she likely considered it a propagation tool. Given the size of the program, over 6 mb, it is likely the initial infection came from a malware laden ad that was placed on a site through the use of a stolen credit card or through a person being tricked into a minor download. Once that infection occurred the ads would be taken over and a new payload would be delivered by controlling the sites/ads the user viewed. The process is piece meal until the full software package is in place and the computer has been zombie-ized. (Please understand I am just theorizing here)
But its criminal uses are so much more. (It should be noted that when I was an FBI agent, I worked undercover online devising criminal schemes with hackers to steal data. One hacker actually called me a “criminal mastermind,” prior to my scheme being run and the FBI busting him/us.)
Everyday hundreds of millions of people view online ads. In fact, online advertising is a $26 billion industry. Companies spend billions to devise better algorithms to serve the right ad to the right user to try to insure a sale. Laws are being bantered around and debated on how to limit what companies can collect about the user and what they can do with the data they do collect.
So if I have a tool that allows me to push my ads to everyone no matter which site they are on and to make sure those users sign up for those offers, well now I’m a billionaire.
To understand this you have to understand the basics of the online ad industry.
Websites charge advertiser a fee for displaying their ads on the site. These fees are either per click aka CPC (someone clicks on your ad, you pay the site $1.00) or per 1000 views aka CPM (your ad is displayed 1000 times on the site, you pay the site $1.00)
But websites owners can not have contact with every advertiser out there. As such they outsource the management and display on their sites to third party ad servers who “serve up the ads on the site.
On the flip side advertisers/companies do not have a large enough sales force to go to all the websites to negotiate CPC and CPM prices and then monitor all the traffic.
Instead they work with ad networks and pay those networks a bounty for every person who comes to the company’s site and signs up. This model is call CPA or cost per acquisition.
But again the ad network is not large enough to handle all the sites to arrange display ads so the ad network sub-contracts the display of advertisement, known as media buys, to independent marketers known as affiliates. In doing this, the affiliate is paid between 80-85% of the bounty/commission the ad network receives from the company/merchant/advertiser but they also have to pay the website owners or ad servers on a CPC or CPM pricing model.
The more traffic and sign ups the affiliate sends through the more money they make. CPA offers can range from $.25 per sign up to $350 per sale.
This is where the abuse, fraud, schemes and scams come into play. The affiliates have to pay to get their ads on certain sites and once there, there is no guarantee people will click on them or sign up for the offer.
How do you get people to click on ads or sign up for offers while spending the least amount of money?
It seems almost every day that “affiliates” come up with new and “interesting” ways to drive traffic and profit, from Flogs (fake blogs) to Content Unlock to Cookie stuffing.
(Online Intelligence, the firm I work for, monitors traffic and its sources to try to insure those signing up for offers are real people and that they were not tricked or misled by the advertisement)
Now we know Zeus was included in the mix.
A Zeus backed botnet can not only determine which advertisement the computer user sees, it can also be used to “sign up” for the offers without the user knowing.
CNN, MSNBC, WSJ, FOX, etc may not have been infected by Zeus. Rather the users’ computer was infected and when they went to those sites, the requests for “ads” were hijacked and the botmaster’s “special” ads were shown instead. Amongst those ads are ads touting investment vehicles that have been revealed to actually be con jobs intent on stealing you money and your banking information, malware downloads and adware. In other cases the ads are only those of a partner affiliate marketer. And without the user knowing the credentials that have been stolen from the computer are being used to sign up for an Acai berry product or a work from home packet. The cost to the consumer is $79.99 per month. The commission payment to the affiliate is $39.50 per sign up; with 100 fake sign ups a day the affiliate is making $3950/day or $122,000 per month. The cost to the affiliate to drive the traffic…. $0.
As a defense to the affiliate marketers, they too may be victims as they may be buying traffic from a third party. These third parties will guarantee a certain amount of website page views per month for a relatively low fee and affiliates will gladly pay, not knowing that the traffic is not real but rather botnet driven.
Some of the third party traffic sellers are bot masters while others are affiliates who have been ban from networks and are now working with/for “cleaner affiliates” (Botnet masters often rent the use of their botnets to others to use as they choose, such as spam, phishing, credential stealing, and now it appears display ads.)
Zeus software also looks to include a “layer technology” piece. For those websites where the software does not hijack/redirect the ad serve calls, it simply fits an overlay on top of the ad space and displays the ad it wants the user to see.
This technique should give website owners and their advertisers pause because, for all intent and purpose the website is delivering an ad to the user and thus charging that advertiser for the ad view but the user never sees the ad as it hidden behind the Zeus overlay.
As such an advertiser could be charged $10,000 a month for ad views but the computer users are only seeing half of those ads because their systems are infected by Zeus.
Additional revelations are that Zeus also steals your social media credentials thus allowing the botmaster to become you, contact all of your friends and direct them to a website where once again he controls the ads or can force a malware download.
It appears all of these “modules” can act independently so a user could be protected against the theft of financial data but not from the ad redirect or the social media credential harvesting.
So next time you are surfing the web and checking out your favorite sites, be leery of that banner ad you see on the top, side or bottom of the page. You don’t know who or what is truly behind that ad.