Suspicious Headless conhost Spawned by Firefox via Process Creation

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1053.005Scheduled Task
Persistence
- T1053.005Scheduled Task
Priv Esc
- T1053.005Scheduled Task
Defense Evasion
- T1564.003Hidden Window
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects firefox.exe spawning conhost.exe in headless mode, an anomalous chain RomCom produces when its scheduled task launches Firefox to run hidden console activity after zero-day exploitation. A browser process starting a headless console host is not normal behavior. This indicates hidden command execution during a RomCom intrusion.

Reporting behind it

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Suspicious Headless conhost Spawned by Firefox via Process Creation

Pivot detection · T1053.005 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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