Users of Google’s Chrome browser have been affected by three security vulnerabilities in the past 24 hours in the form of a malicious extension with over 2 million users, a just-fixed zero-day, and new information about how malware can compromise Chrome’s sync feature. abuse it to bypass the browser. firewalls. Let’s discuss them one by one.
First, the Great Suspender, an extension with over 2 million downloads from the Chrome Web Store, has been pulled from Google’s servers and removed from users’ computers. The extension has been an almost essential tool for users with small amounts of RAM on their devices. Since Chrome tabs are known to consume large amounts of memory, the Great Suspender temporarily suspends tabs that have not been opened recently. This allows Chrome to run smoothly on systems with modest resources.
Characteristically concise
Google’s official rationale for the removal is characteristically succinct. Messages displayed on devices with the extension installed will only say “This extension contains malware” along with an indication that it has been removed. A Google spokesperson declined to elaborate.
The longer backstory is that, as reported in a November GitHub thread, the original extension developer sold it last June, and it started showing signs of malice under its new owner. Specifically, the thread said that a new version contained malicious code that tracked users and manipulated web requests.
The automatic removal has left some users in the lurch as they can no longer easily access suspended tabs. Users in this Reddit thread have come up with several ways to restore their tabs.
Zero-day with high severity
Then, on Thursday, Google released a Chrome update that fixes what the company said was a zero-day vulnerability in the browser. Tracked as CVE-2021-21148, the vulnerability stems from a buffer overflow flaw in V8, Google’s open source JavaScript engine. Google rated the severity as ‘high’.
Again, Google provided minimal information about the vulnerability, saying only that the company is “aware of reports that an exploit for CVE-2021-21148 exists in the wild.”
However, in a post published Friday by security firm Tenable, researchers noted that the flaw was reported to Google on Jan. 24, a day before Google’s threat analysis group dropped a bombshell report that hackers sponsored by a nation state had launched a malicious website. used to infect security researchers with malware. Microsoft released its own report speculating that the attack exploited a Chrome zero-day.
Google declined to comment on that speculation or provide further details about exploits of CVE-2021-21148.
sync abuse
Finally, a security researcher reported on Thursday that hackers used malware that exploited the Chrome sync feature to bypass firewalls, allowing the malware to connect to command and control servers. Sync allows users to share bookmarks, browser tabs, extensions, and passwords across devices running Chrome.
The attackers used a malicious extension that was not available in the Chrome Web Store. The link above offers a wealth of technical details.
A Google spokesperson said developers won’t change the sync feature because physically local attacks (i.e. attacks where an attacker gains access to the computer) are explicitly outside Chrome’s threat model. He included this link, which further explains the reasoning.
None of these concerns mean you need to uninstall Chrome or even the sync feature. Still, it’s a good idea to check what version of Chrome you have installed to make sure it’s the latest version, 88.0.4324.150.
The usual advice about browser extensions also applies, which is to install them only if they are really useful and after vetting the security in users’ comments. That advice wouldn’t have saved Great Suspender users, though, which is exactly the problem with extensions.