Cybersecurity researchers have recognized a complicated new command-and-control framework that exploits professional Google Calendar APIs to ascertain covert communication channels between attackers and compromised programs.
The MeetC2 framework, found in September 2025, represents a regarding evolution in adversarial ways the place menace actors abuse trusted cloud companies to bypass conventional safety controls and evade detection mechanisms.
The framework operates by masquerading malicious site visitors as routine enterprise communications by means of Google’s widely-trusted domains, particularly “oauth2.googleapis.com” and “www.googleapis.com”.
This strategy permits malicious actions to mix seamlessly with regular organizational site visitors, making detection considerably tougher for safety groups.
The cross-platform compatibility throughout macOS and Linux programs additional amplifies its potential impression on numerous enterprise environments.
Deriv Tech researchers famous that the framework’s design demonstrates a complicated understanding of recent safety architectures and cloud service abuse strategies.
The proof-of-concept implementation highlights how simply adversaries can leverage professional SaaS platforms for malicious functions, exploiting the inherent belief organizations place in main cloud suppliers.
The assault methodology facilities round a polling-based communication system the place compromised brokers ship GET requests each 30 seconds to particular Google Calendar API endpoints.
When operators must subject instructions, they create calendar occasions with embedded directions within the abstract subject, formatted as “Assembly from no one: [COMMAND]”.
Assault chain (Supply – Medium)
The sufferer agent identifies these command occasions throughout common polling cycles, extracts the instructions, executes them regionally, and updates the identical calendar occasion with execution outcomes embedded inside [OUTPUT] [/OUTPUT] parameters within the description subject.
Technical Implementation and Evasion Mechanisms
The MeetC2 framework’s technical structure reveals refined evasion capabilities that exploit the ubiquity and trusted nature of Google companies.
The authentication course of makes use of normal OAuth2 flows, requiring attackers to create professional Google Cloud Console tasks and repair accounts with calendar entry permissions.
This strategy ensures all communications seem as approved API interactions somewhat than suspicious community site visitors.
The implementation requires minimal infrastructure, working solely by means of Google’s present Calendar API infrastructure.
Operators authenticate by means of service accounts configured with “Make modifications to occasions” permissions on shared calendars.
The polling mechanism employs a 30-second interval, hanging a stability between operational responsiveness and avoiding extreme API requests that may set off charge limiting or suspicious exercise alerts.
Code execution happens by means of command extraction from calendar occasion summaries, with outcomes uploaded again to the identical occasion’s description subject.
This bidirectional communication mannequin creates an entire command-and-control channel whereas sustaining the looks of professional calendar synchronization actions.
The framework helps focused command execution utilizing host-specific syntax like “exec @host:command” or broadcast instructions throughout a number of compromised programs concurrently.
The persistence and stealth traits of MeetC2 make it notably regarding for enterprise safety groups, because the framework generates no suspicious community patterns and leverages companies that organizations explicitly whitelist for enterprise operations.
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