Google has taken a swipe at those responsible for a spate of cases of “ad injection” around the web.  

The search giant claims to have seen evidence of software, commonly attached to browser extensions and web apps, which inserts new ads or replaces existing ones without the publisher’s permission. 

Following its tests from last year, Google has slammed known injection ‘libraries’ including Superfish and Jollywallet, who work with ad networks to decide which ad goes where. Criticism has also been directed at the networks hosted by, and 

It’s an issue that appears to be playing close to Google’s heart, as along with Amazon and Walmart, the company’s own search engine appears to have been affected by cases of ad injection.

The company has published the results of its first clampdown on ad injectors and isn’t pulling any punches in terms of whom it feels the blame is on.

The issue at hand

As part of a study with the University of California, Berkeley and Santa Barbara, conducted last year, Google built a custom ad injection “detector” which ended up identifying “tens of millions” of instances of ad injection in the webosphere. 

Findings from the report discovered that 5.1% of page views on Windows machines and 3.4% on Mac will show cases of ad injection.

Google says that a network of affiliates are being hired to bring ad injector software out to the masses through packaging it up with other titles. In some cases, it will be through the outright distribution of malware, with the publishers paid for every download driven.    

Although Google cited this as an issue back in March, today (May 6) marked the first time that it has actually started calling companies out. 

Results show that 77% of injected ads are passing through networks owned by, and, which are causing advertisers like eBay and Sears to pay for any traffic obtained. 

As for the companies with links to affiliate downloads, Crossrider, Shopper Pro and Netcrawl have been cited as offenders in this vein. 

One of the reasons why ad injectors have been allowed to grow in prevalence is due to the attribution models favoured by brands. As so many advertisers work on a last-click model, Google says they are unable to see the full picture unfolding. 

Clamping down

As expected, Google hasn’t taken the news lightly and has already outlined some of the steps being taken in light of the findings being released. 

A total of 192 extensions for Google Chrome have been removed on suspicion of carrying injectors, while new safeguards have been deployed within the Chrome Web Store to flag more examples of malicious software. 

Not only this, Google is also informing some of the advertisers that areas of their campaigns are being subjected to ad injection software, although plenty of damage has already been done.

A full report from Google’s storm on ad injectors is to be unveiled at a web security event in California on the week commencing May 18.