“Truth in advertising” can sometimes seem like a contradiction, but this much we know for sure: The combination of malware and advertising, or malvertising, is not only growing substantially, but also becoming more difficult to detect.

Security firm Cyphort, for example, recently published a blog post outlining a malvertising campaign running across sites in Japan, Indonesia and Vietnam, among others. Unlike similar campaigns that simply embedded malicious code or an exploit kit inside an online ad, Cyphort told CSO Online cybercriminals are deploying a series of redirect URLs over an AOL-owned ad network that uses secure socket layer (SSL) protection. Only after three different redirects does a victim wind up at a malware-laden site. There, victims may be hit by a zero-day exploit kit to take over their machine, steal data and potentially demand payment.

Unfortunately, this may only be the tip of a particularly large iceberg. Another security firm, Invincea, recently published a report that called June the worst month on record since malvertising first emerged as a tactic. Its data shows high-profile sites such as Yahoo, eBay UK and CBS Sports among those connected to ad networks serving up malware. That suggests cybercriminals might be using money they’ve gained through other attacks to bid on prime online ad spots, where they use a variety of exploit kits, often based on problems with Adobe’s Flash Player plugin.

In a recent interview with ITProPortal, a malware intelligence analyst at Malwarebytes said zero-day attacks work particularly well with malvertising. That’s because not all online ad networks are as scrupulous when looking out for dangerous content or ensuring they’re working with legitimate customers. Attacks are therefore not only difficult to predict, but the payloads used can vary widely, from banking Trojans and keyloggers to ransomware and other demands for payment.

All this could explain why, according to The Wall Street Journal, the Interactive Advertising Bureau has made the use of ad-blocking technology a high priority for its members this year. Although there could be some financial downside to keeping more online ads at bay, the ability to hide malvertising in SSL redirects may soon leave the industry with little choice to do otherwise.