Malvertising is a consistent challenge which can see reputable websites having frames infected to serve up any matter of attack.
After Yahoo beat down malicious advertisements which redirected users to the “Magnitude” exploit kit, which was enabled following the infection of a third party, Sean Power, security operations manager at DOSarrest, said that the problem is that many banner ad companies allow JavaScript or other code inside the advert.
“This is something we have seen before. In our case it was an advertising campaign that included a DDoS attack against one of our customers,” he said. “For companies allowing these ads on their website, the ads should be sanitised before displaying to the public.”
Power said that businesses should find a balance of risk versus profit to deal with this type of attack, and techniques could range from simply “trusting that all ads are malware free” to digitally signing each ad and only showing the ones that have been verified as malware free.
He also said the responsibility should lie with the ad company to sanitise all of its ads; although he pointed out all of the bad press will be focused on the site displaying the ads (in this case Yahoo). “No one is going to take kindly to a “not my responsibility” attitude when they got a virus after visiting your site,” Power concluded.
“As with any other business relationship – do your due diligence. Find out if the ad company allows code to be inserted in the ads. Anytime your business relationships have the ability to directly alter your customer’s experience, they should be part of your security review,” he said.
Also hit by malicious adverts was video-sharing website Dailymotion, which according to research by Invincea delivered a malicious executable file as a ruse to “clean” their “infected” machine. Visitors were automatically redirected via Javascript to a website that distributed the fake infection warning, and this then automatically serves up the fake anti-virus.
Luis Corrons, technical director of PandaLabs, told IT Security Guru that adverts can lead to exploit kits and that has happened a number of times in the past. “In this kind of attack, the site serving the malicious advert has not been compromised, so I won’t say the responsibility to sanitise the ads lies directly with them,” he said.
“However, it is in the company’s own interest to protect people using their website. The company serving the ads is the one that should hold most of the responsibility, as it is their platform the one being abused.”
