Google Warns How Hackers Could Abuse Calendar Service as a Covert C2 Channel
Nov 06, 2023
Cyber Attack / Online Security
Google is warning of multiple threat actors sharing a public proof-of-concept (PoC) exploit that leverages its Calendar service to host command-and-control (C2) infrastructure. The tool, called Google Calendar RAT (GCR) , employs Google Calendar Events for C2 using a Gmail account. It was first published to GitHub in June 2023. "The script creates a 'Covert Channel' by exploiting the event descriptions in Google Calendar," according to its developer and researcher Valerio Alessandroni, who goes by the online alias MrSaighnal. "The target will connect directly to Google." The tech giant, in its eighth Threat Horizons Report [PDF], said it has not observed the use of the tool in the wild, but noted its Mandiant threat intelligence unit has detected several threat actors sharing the PoC on underground forums. "GCR, running on a compromised machine, periodically polls the Calendar event description for new commands, executes those commands on the t...