It’s not a new threat on the scene, but it’s still dangerous — and malvertising on the web is on the rise.
Malvertising is the spread of malware through online advertising, and it’s pretty ugly. It’s especially prescient as ads on the web have been challenged by a number of technical factors in browsers, the progressive changeover to HTML5 from Flash technology, and the emergence of app blockers in places like the Apple App Store.
In recent years, the spread of malware transmitted through ads has grown exponentially, by some estimates quadrupling in size from year to year. The threat is major, and with every malvertising infection, the potential for hackers to execute arbitrary code on a base of infected computers increases. The scale and sophistication of attacks continues to march on, and much of the response has hinged on fighting fires as outbreaks pop up. Some worry that this explosion will change the very nature of advertising networks and how we view ads on the web.
A plague is out there
An ugly malvertising campaign on the website Realtor.com last week exploited unpatched systems, and this particular campaign is especially worrisome for one reason: It’s the latest in a string of attacks that don’t even require your click on a bogus advertisement to trigger an infection. Realtor.com gets an estimated 30 million visits a month, which means as many as a million people may have been exposed to the malware in a single day. According to the MalwareBytes blog, the payload in this case appeared to be the Bedep Trojan, which can hijack browsers and install ransomware. Yahoo, Forbes, YouTube, and other major websites join a lengthy list of companies that have been affected by these ads.
Follow the flow this diagram and you’ll witness the appeal of spreading malware through these means. By all measurable information, the campaigns appear compelling and profitable — that’s why we’re seeing such see a concerted effort to produce convincing advertisements with products that appear genuine. The black market for the zero-day vulnerabilities implemented in these malvertising attacks also indicates investment and effort. The very placement of ads also incurs an operational cost.
It’s also interesting to consider that the very same base of information that makes advertising targeted and personal has become the target for spreading specific malware. The parties behind this surge in malvertising have targeted ad networks and websites so far. It may be a matter of time only before they micro-target certain individuals within an organization or within government through these innovative techniques. Cyber security usually boils down to a race to find the point of least resistance — and the latest front may very well be malvertising.
The best way to deal with these threats is to keep your browser, plugins, and operating systems up to date. Always use an anti-virus product to protect your systems, and when required, use a malware tool to perform cleanups. let’s be safe out there, everyone.
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