New malware turns Microsoft 365 and Azure into its control center

The pathway is different from Edge transport. The implant launches Microsoft Edge in headless mode, attaches through the Chrome DevTools Protocol, and issues Graph API calls as “same-origin fetch ()” requests from within the browser. From network telemetry, it looks like a legitimate Edge process communicating with Microsoft, the researchers said.

Commenting on the detection complications TWINLOOT adds, Robert Coles, senior manager of threat intelligence security at Black Duck, said, “Attackers are increasingly hiding inside trusted cloud services rather than using attacker-controlled infrastructure.” He recommended focusing on behavioral detection, identity monitoring, and anomaly detection, including unusual Graph API activity, OAuth applications and consent grants, and anomalous SharePoint and Teams behavior.

Stealing credentials and persisting without admin rights

On command, TWINLOOT displays a Windows 10 or Windows 11 lock screen populated with the victim’s real account information. It never validates the password. Instead, every password attempt is captured, encrypted, and sent to the SharePoint C2 channel. The victim receives a normal-looking incorrect password message before eventually authenticating the login.

About Author

AndyC

Andy Curtis is an award-winning security consultant, researcher and public speaker. He has been working in the computer security industry since the early 1990s, having been employed by state and federal government, leading healthcare and banking providers across three continents. He has given talks about computer security for some of the world’s largest companies, worked with law enforcement agencies on investigations into hacking groups, and is a regular voice on TV and radio explaining IT security threats.

See author's posts