Chinese state-sponsored group exploiting Microsoft Exchange ProxyLogon zero-days (CVE-2021-26855) to compromise 30,000+ organizations globally. This profile is mapped to MITRE ATT&CK G0125 and covers attribution, tooling, targeting, and defensive recommendations based on observed campaigns.
Overview & Attribution
HAFNIUM (also tracked as Silk Typhoon) is a threat group attributed to China. The group primarily targets US defense, legal, universities, think tanks for intelligence collection and operational objectives aligned with state interests.
This group is tracked as G0125 in the MITRE ATT&CK framework. All techniques referenced in this report are mapped to ATT&CK for consistent threat modeling and detection engineering.
Arsenal & Tools
Known tools and malware associated with HAFNIUM include:
- China Chopper
- SIMPLESEESHARP
- ASP web shells
Targeting & Operations
HAFNIUM operations focus on US defense, legal, universities, think tanks. The group typically gains initial access through spear-phishing, exploitation of public-facing applications, or strategic web compromises before deploying custom implants for persistent access and data exfiltration.
Organizations in the US defense sector should treat HAFNIUM as a relevant threat and validate their detection coverage against the MITRE ATT&CK techniques listed below.
MITRE ATT&CK Mapping
Key techniques observed in HAFNIUM operations:
| Technique ID | Technique Name | Tactical Context |
|---|---|---|
| T1190 | T1190 | Observed in HAFNIUM campaigns |
| T1505.003 | T1505.003 | Observed in HAFNIUM campaigns |
| T1003.001 | T1003.001 | Observed in HAFNIUM campaigns |
| T1071.001 | T1071.001 | Observed in HAFNIUM campaigns |
Full ATT&CK mapping: https://attack.mitre.org/groups/G0125/
Notable Campaigns
This threat group has been active in operations targeting US defense, legal, universities, think tanks. Security researchers have documented campaigns involving China Chopper and other tools deployed against organizations in multiple countries. Attribution confidence varies by campaign, but consistent infrastructure and TTP overlap links activity to China-nexus operations.
Detection & Defense
Recommended defensive measures against HAFNIUM:
- Network monitoring: Detect C2 beaconing patterns associated with China Chopper and related implants
- Endpoint detection: Deploy behavioral rules for the ATT&CK techniques above, particularly T1190 and T1505.003
- Email security: Implement robust phishing defenses including URL sandboxing and attachment detonation
- Patch management: Prioritize patching of internet-facing applications exploited by this group
- Threat hunting: Proactively hunt for IOCs and behavioral indicators mapped to G0125 in MITRE ATT&CK
How Mjolnir Security Can Help
Defend Against HAFNIUM
Mjolnir Security provides tailored threat intelligence, detection engineering, and incident response services to help organizations defend against China-nexus threat actors.
Contact us: mjolnirsecurity.com
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