A threat actor operating with interests aligned with North Korea has been deploying a malicious extension on Chromium-based web browsers that's capable of stealing email content from Gmail and AOL. Cybersecurity firm Volexity attributed the malware to an activity cluster it calls SharpTongue, which is said to share overlaps with an adversarial collective publicly referred to under the name Kimsuky. SharpTongue has a history of singling out individuals working for organizations in the U.S., Europe, and South Korea who "work on topics involving North Korea, nuclear issues, weapons systems, and other matters of strategic interest to North Korea," researchers Paul Rascagneres and Thomas Lancaster said. Kimsuky's use of rogue extensions in attacks is not new. In 2018, the actor was seen utilizing a Chrome plugin as part of a campaign called Stolen Pencil to infect victims and steal browser cookies and passwords.