HOLLOWGRAPH malware turns Microsoft 365 calendars into an espionage channel

Microsoft 365 calendars have become a hiding place for espionage malware, with commands and stolen files stashed inside appointments dated to the year 2050, researchers from …

First seen on helpnetsecurity.com

Jump to article: www.helpnetsecurity.com/2026/07/20/hollowgraph-malware-microsoft-365-calendar/