Suspicious Chrome Malicious Extension Deployment via StormBamboo

ATT&CK techniques

Persistence

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1176Software Extensions
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects creation of files under the CustomPlug1n extension directory used by StormBamboo to sideload the RELOADEXT malicious Chrome extension. The actor tampered with Chrome Secure Preferences to force-load the extension after compromising software update mechanisms. Malicious browser extensions enable credential theft and traffic interception.

Reporting behind it

Related detections9 linkedT1176 — drag to rearrange

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Malicious GenAI Browser Extension C2 and PAC Redirection (via proxy)

Suspicious Microsoft Edge Headless Launch with Unpacked Extension via SNOWBELT (via process_creation)

Suspicious Browser Extension Force-Install via Registry (via registry_set)

Suspicious Microsoft Edge Native Messaging Host Registration via UNC6692

Malicious Madgicx Plus Chrome Extension Identifiers on Disk

Suspicious Browser Extension Sideload From a User Path (via process_creation)

Suspicious Chrome Remote Debugging Port for Browser Session Theft

Suspicious Microsoft Edge Unpacked Extension Load via UNC6692 Edgecution

Suspicious Chrome Malicious Extension Deployment via StormBamboo

Pivot detection · T1176 · 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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