HollowGraph Malware Uses Microsoft 365 Calendar Events as Dead-Drop C2 Channel

What Happened On July 20, 2026, cybersecurity firm Group-IB disclosed a new espionage implant dubbed HollowGraph that hijacks compromised Microsoft 365 mailboxes to run a command-and-control (C2) channel hidden inside calendar events. The malware attaches encrypted files to calendar entries date...

Source: [Dev.to](https://dev.to/alejandxr/hollowgraph-malware-uses-microsoft-365-calendar-events-as-dead-drop-c2-channel-5h02)