OTX Threat: HOLLOWGRAPH: Turning Microsoft 365 Calendars into Covert Command-and-Control Channels

A sophisticated espionage campaign has been identified leveraging malware that exploits Microsoft Graph API to transform compromised Microsoft 365 calendars into covert command-and-control infrastructure. The malware creates calendar events dated to 2050 with encrypted attachments to exfiltrate files and receive instructions. A secondary DNS tunneling channel using IPv6 AAAA records refreshes Micr