Researchers at BlueVoyant observed a 50% increase in large-scale malvertising campaigns in 2023 compared to 2022.

“Fraudulent search engine ads appear as benign advertisements, almost indistinguishable from legitimate ones,” the researchers write.

“This makes ads a highly effective distribution mechanism since users often rely on the top search result rather than directly typing in a domain. When setting up a malicious ad campaign, threat actors utilize the various customization options available for advertisers as a sophisticated evasion mechanism, displaying the ads only to specific users to meet predefined criteria.”

These criteria enable attackers to tailor their malvertising campaigns to target specific areas and groups of people. 

“These restrictions allow threat actors to pick and choose the most vulnerable and profitable victim profiles and present their ads only to them while evading detection by security vendors,” the researchers write. “Combined with evasion mechanisms employed by phishing kits (IP blocklisting, redirection, and more), campaigns taking advantage of ad targeting customizations are much trickier to detect. 

Attackers have started to implement additional measures to avoid detection by security tools.

“In researching several such phishing campaigns, BlueVoyant analysts observed an unusual added layer of evasion used to distinguish actual users (organically redirected to the phishing site from the ad) from any bots/security vendors,” the researchers write. “Once a user clicks on the malicious ad link and is being redirected to the site, a unique session cookie is created.

Without the cookie, the phishing content will not be displayed on the website. Instead, the user will find a benign, unrelated landing page, or will be redirected to another domain. In addition, phishing ads may also link to lookalike domains of the impersonated brand in the URL section of the ad, which redirects the victim to a non-lookalike phishing website. This makes the ad itself look even more legitimate.”

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BlueVoyant has the story.