A set of malicious Google Chrome extensions designed to monitor browsing activity have been installed on more than 1.4 million devices, researchers have reported.
As described in a blog post from security company McAfee, the purpose of the scam is to modify the victim’s browser cookies each time they visit an ecommerce website, thereby netting the operator an affiliate fee for any purchases made.
Although two extensions branded as “Netflix Party” have now been removed from the official extension marketplace, McAfee says the remainder are still available to download.
Chrome extensions scam
Although the malicious extensions do not pose an immediate security risk – they are not designed to exfiltrate sensitive data, nor install malware payloads – they do represent a flagrant violation of privacy.
As demonstrated by the surging popularity of VPN services and other solutions designed to obscure web activity, modern web users are increasingly unwilling to part with their browsing data - and especially not, one would imagine, in these circumstances.
What makes this scam particularly difficult to spot is that the extensions all serve a legitimate purpose, on top of providing a foundation for the affiliate revenue ploy. They are also broadly well-reviewed, leaving potential victims with little indication of the scam playing out under their noses.
“The extensions offer various functions such as enabling users to watch Netflix shows together, website coupons, and taking screenshots of a website,” explained McAfee.
“The users of the extensions are unaware of [the malicious functionality] and the privacy risk of every site being visited being sent to the servers of the extension authors.”
In an effort to evade detection by analysts, meanwhile, the operators programmed some of the extensions to begin meddling with browser cookies multiple weeks after the date of installation.
Chrome users that find they have installed the offending extensions are advised to perform a manual uninstall immediately.
Malicious extensions list:
- Netflix Party
- Netflix Party 2
- Full Page Screenshot Capture - Screenshotting
- AutoBuy Flash Sales
Update: 09 September, 2022
The original version of this article made reference to a browser extension that has since been updated to remove the functionality identified by McAfee as malicious.
In communication with TechRadar Pro over email, McAfee provided the following statement:
"Since the original publication of the report on August 29, 2022, the browser extension was updated in the Chrome Store on September 6, 2022. McAfee has updated its blog accordingly."
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