Description

Competition between macOS stealers is intensifying, with a new malvertising campaign targeting Mac users through a fake Microsoft Teams ad. This attack follows the Poseidon (OSX.RodStealer) project, which uses a similar code base and delivery methods. Threat actors are now using Microsoft Teams as a lure, a first for Atomic Stealer. Historically, criminals have used fake installers for tools like Zoom, Webex, and Slack to distribute malware. The recent malvertising campaign, operational for several days, employed sophisticated filtering methods to evade detection. Upon replicating the entire malware delivery chain, we promptly reported the malicious advertisement to Google. Searches for Microsoft Teams led to a top search result featuring the malicious ad, likely paid for via a compromised Google ad account. Initially, the ad redirected to Microsoft’s site, but after numerous attempts, the full attack chain was observed. The ad's malicious nature was confirmed through network capture. Each click was first profiled by smart[.]link, followed by a cloaking domain (voipfaqs[.]com), leading to the malicious landing page (teamsbusiness[.]org). Victims were shown a download button for Teams, leading to a unique payload from locallyhyped[.]com. The downloaded file, MicrosoftTeams_v.(xx).dmg, required a right-click to open, bypassing Apple’s protection for unsigned installers. Installation instructions prompted users to enter their password and grant file system access, enabling Atomic Stealer to capture keychain passwords and important files. Data theft was followed by data exfiltration, visible only through network packet collection. A single POST request was made to a remote server (147.45.43[.]136), with the data encoded. For detailed steps and further insights, visit the Microsoft support website.