A malicious component dubbed HollowGraph uses the calendar feature in compromised Microsoft 365 mailboxes as a command-and-control channel to receive attacker commands and exfiltrate stolen data.

A Linux variant of the GoGra backdoor uses legitimate Microsoft infrastructure, relying on an Outlook inbox for stealthy payload delivery. The malware is developed by Harvester, an espionage group ...

DavMail 7.0.0 turns on Graph delta sync by default, drops the caldavImpersonate setting, and now locks down its token file on Linux machines.