Microsoft 365 calendars become spy drop boxes in HOLLOWGRAPH campaign

Microsoft 365 calendars have become the latest hiding place for espionage malware, with attackers stashing commands and stolen files inside appointments dated 24 years into the future. Researchers at Group-IB say they've uncovered a malware component they call HOLLOWGRAPH that swaps the usual command-and-control server for something rather less conspicuous – a compromised Microsoft 365 calendar. Instead of reaching out to attacker-controlled infrastructure for instructions, the implant rum