Many people hate online ads because they create annoying distractions on websites, but research from Google and several universities suggest ad injectors are also a security risk.

The Google Online Security Blog outlined a new study on the ad injection economy, which was carried out by researchers at Google along with the University of California, Berkeley and the University of California, Santa Barbara. The report described a mechanism used to detect unwanted software that uncovered more than 85,000 ad injectors aimed at the Chrome browser. Besides taking control of the browser, the research suggested that 30 percent of such extensions and apps were stealing data and reporting it back to third parties. The data could include anything from browser queries to more serious information, such as online account credentials.

Although not all ad injectors are the work of cybercriminals, eWEEK pointed out that they are often distributed in ways that would categorize them as malware. This could include online campaigns that trick users into clicking on special URLs or even via ad affiliation networks, which can profit from each click that comes through such programs. Advertisers might not even realize where some of the traffic to their ads originated.

AdExchanger, an online magazine aimed at the digital marketing industry, suggested Google’s findings would raise major concerns from companies that run campaigns online. Some may already be on the alert after a recent scandal involving Superfish, whose technology for switching online ads reportedly opened up Lenovo laptop users to hacker activity.

The report showed some very well-known brands whose ads are being served up via ad injectors, including Wal-Mart, eBay and Sears. Although the main culprits may be limited to less than a handful of programs, The Wall Street Journal suggested that resolving this issue could prove highly challenging. Google and others could conceivably create tools to block unwanted ads, but it would probably be quicker if more publishers and brands became more aware of the issue and how it could hurt their customers.

The Verge made another good point: Although Google’s research suggested that 1 in 20 online users are victims of ad injectors, that may be a conservative number. Much like other forms of malware, those looking to serve up unwanted ads and steal information try to be as difficult to detect as possible. The report may have opened a can of worms, but we probably still haven’t seen the bottom of the can.