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“The script we first observed was injected via a script tag pointing to a remote server where the AllBlock extension injects the malicious code directly to the active tab,” Imperva’s report revealed. They couldn’t identify the origin of the attack because of the way the malicious script was injected. According to Imperva, scammers are probably using other extensions in this campaign. It is yet unclear how AllBlock is distributed or promoted. In AllBlock ad injection scam, Imperva researchers were able to find the script in bg.js that they had been looking for since August. Consequently, when a user clicked on an altered link, they were redirected to another page, usually an affiliate link.Īd injection scripts may feature evasion techniques like excluding Russian search engines, active detection of Firebug variables, and clearing the debugging console after every 100ms. Imperva researchers identified such a campaign in August 2021 where several previously unknown domains were found to be distributing an ad injection script that would send legit URLs to a remote server and, in response, obtained a list of redirection domains. Scammers can earn money from advertisements by injecting unrelated ads or redirect unsuspecting users to affiliate links to earn a commission. It has now been removed from Opera add-ons and Chrome Web Store.Īd injection is a method of inserting ads or links into a web page that isn’t supposed to host them. AllBlock was available on Google Chrome’s Web Store where it is marketed as a potent Ad Blocker focusing on Facebook and YouTube to prevent pop-ups. The payload then retrieves a series of unwanted ads, most of which are not from legitimate sources, and includes affiliate links. Via this affiliate fraud, the attacker earns money when specific actions like registration or sale of the product take place,” Imperva researchers observed.
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“When the user clicks on any modified links on the webpage, he will be redirected to an affiliate link. This code communicates to remote servers and download/installs a payload connected to an ad-injection scam’s operators. Security vendor Imperva’s Sillam and Ron Masas reported that a Google Chrome extension called AllBlock designed to block ads is injecting ads into Chrome and Opera.Īlthough the extension blocks ads, it runs a script in the background that injects a piece of JavaScript code into every tab that the user opens. Chrome’s Ad-Blocker Extension Displaying Ads on Google However, the new report from Imperva reveals that maybe Google isn’t performing its job as sincerely as it claims to be.
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Google has maintained that it takes the security of Chrome extensions very seriously and regularly vets them to prevent exploitation.
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