Malicious 3CX Second-Stage C2 Icon Retrieval from GitHub IconStorages (via dns_query)

ATT&CK techniques

Defense Evasion → C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1071.001Web Protocols
Exfiltration
Impact

What it detects

This rule detects the 3CX desktop application resolving raw.githubusercontent.com, which the second stage contacts to fetch ICO files from the IconStorages repository hiding encoded C2 configuration. This beacon follows a dormancy period and precedes browser credential theft in the supply chain intrusion.

Reporting behind it

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Malicious 3CX Second-Stage C2 Icon Retrieval from GitHub IconStorages (via dns_query)

Pivot detection · T1071.001 · 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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