An anonymous reader quotes a report from Forbes: According to cyber security firm Volexity, the threat research team has found the North Korean 'SharpTongue' group, which appears to be part of, or related to, the Kimsuky advanced persistent threat group, deploying malware called SHARPEXT that doesn't need your Gmail login credentials at all. Instead, it "directly inspects and exfiltrates data" from a Gmail account as the victim browses it. This quickly evolving threat, Volexity says it is already on version 3.0 according to the malware's internal versioning, can steal email from both Gmail and AOL webmail accounts, and works across three browsers: Google Chrome, Microsoft Edge, and a South Korean client called Whale.
The U.S. Cybersecurity & Infrastructure Security Agency, CISA, reports that Kimsuky has been operating since 2012, and is "most likely tasked by the North Korean regime with a global intelligence gathering mission." While CISA sees Kimsuky most often targeting individuals and organizations in South Korea, Japan, and the U. S., Volexity says that the SharpTongue group has frequently been seen targeting South Korea, the U. S. and Europe. The common denominator between them is that the victims often " work on topics involving North Korea, nuclear issues, weapons systems, and other matters of strategic interest to North Korea."
The report says that SHARPEXT differs from previous browser extensions deployed by these hacking espionage groups in that it doesn't attempt to grab login credentials but bypasses the need for these and can grab email data as the user reads it. The good news is that your system needs to be compromised by some means before this malicious extension can be deployed. Unfortunately, we know all too well that system compromise is not as difficult as it should be. Once a system has been compromised by phishing, malware, unpatched vulnerabilities, whatever, the threat actors can install the extension using a malicious VB script that replaces the system preference files. Once that's done and the extension runs quietly in the background, it is tough to detect. The user logs in to their Gmail account from their normal browser on the expected system.
The security researchers recommend "enabling and analyzing PowerShell ScriptBlock logging" to detect whether you've been targeted by this attack, reports Forbes. Additionally, they recommend reviewing installed extensions regularly, especially looking for ones you don't recognize or are not available from the Chrome Web Store.