Chinese APT Typhoon Family: 20 IOCs for Volt, Salt, Flax, and Brass Typhoon
- Patrick Duggan
- Nov 30, 2025
- 4 min read
Updated: Aug 11
TL;DR: We published an OTX pulse with 20 IOCs covering the Typhoon family of Chinese state-sponsored APTs. Volt Typhoon pre-positions in critical infrastructure. Salt Typhoon intercepts telecom traffic. Taiwan faces 2.4 million cyberattacks daily. Free. No paywall.
The Typhoon Threat
Microsoft's naming convention tells the story: Weather + Country = APT. The Typhoon family represents Chinese state-sponsored groups, and they're among the most sophisticated actors operating today.
The Four Typhoons:
• Volt Typhoon: Critical infrastructure pre-positioning (utilities, communications, transportation)
• Salt Typhoon: Telecom interception (compromised T-Mobile, AT&T, Verizon networks)
• Flax Typhoon: IoT botnet operations (compromised SOHO routers)
• Brass Typhoon: Southeast Asia espionage focus
Taiwan: Ground Zero
Taiwan faces an unprecedented cyber assault:
• 2.4 million cyberattacks daily on government networks
• 150% surge in 2024 compared to 2023
• Critical infrastructure targeting: Power grid, telecommunications, transportation
• Pre-positioning doctrine: Compromise now, activate during crisis
The Taiwan situation isn't just about data theft. It's about pre-positioning access for potential kinetic conflict. Volt Typhoon specifically targets systems that would be critical during military operations.
Salt Typhoon: The Telecom Nightmare
Salt Typhoon's telecom campaign is one of the most significant cyber espionage operations discovered:
• T-Mobile network infrastructure
• AT&T communications systems
• Verizon network components
• Lumen Technologies
• Call detail records (who called whom, when, for how long)
• Text message metadata
• Potentially voice communications
• Lawful intercept systems (wiretap infrastructure)
Why it matters: Accessing lawful intercept systems means they could see who the US government was surveilling. They know which targets were under investigation.
The Living-off-the-Land Doctrine
Volt Typhoon pioneered "living-off-the-land" (LOTL) techniques:
• `ntdsutil.exe` - Active Directory dump
• `wmic.exe` - Shadow copy deletion
• `netsh.exe` - Firewall manipulation
• `reg.exe` - Registry credential harvesting
• `certutil.exe` - File downloads
• `procdump.exe` - LSASS credential dump
• No malware to detect
• No signatures to match
• Native Windows tools
• Blends with normal admin activity
This is why we included YARA patterns in the pulse - detecting the command patterns rather than malware signatures.
The Pulse
Chinese APT Typhoon Family - Volt/Salt/Flax/Brass (Taiwan/Singapore/ASEAN) - DugganUSA
20 IOCs | Subscribe
• 8 C2 IP addresses (confirmed infrastructure)
• 4 CVEs (initial access vectors: Palo Alto, Ivanti, FortiGate)
• 8 YARA patterns (LOTL command detection)
• MITRE ATT&CK mapping (T1190, T1133, T1078, T1003, T1057, T1040)
Microsoft pulls this feed daily. AT&T pulls this feed daily. Starlink pulls this feed daily. Get the DugganUSA STIX feed — $9/mo →
CVE Arsenal
The Typhoon family exploits edge devices - VPNs, firewalls, and remote access solutions:
CVE-2024-3400 (Palo Alto GlobalProtect) - CVSS: 10.0 - Status: Actively exploited - Volt Typhoon: Primary initial access
CVE-2023-46805 + CVE-2024-21887 (Ivanti Connect Secure) - CVSS: 8.2 + 9.1 - Status: Chained exploitation - All Typhoon variants observed
CVE-2023-27997 (FortiGate SSL-VPN) - CVSS: 9.8 - Status: Actively exploited - Volt Typhoon vector
The pattern: Edge devices are the new perimeter. Compromise the VPN concentrator, and you're inside the network.
Regional Impact
Taiwan - Presidential Office targeted - Ministry of National Defense probed - Critical infrastructure pre-positioned - Academia targeted for tech secrets
Singapore - Government networks targeted - Financial sector reconnaissance - Regional communications hub value
Philippines - South China Sea territorial disputes - Military intelligence targeting - US military base adjacency
ASEAN broadly - Thailand, Indonesia, Malaysia - Diplomatic communications - Economic intelligence
Detection Strategies
Network-level: 1. Monitor for unusual outbound traffic to edge device C2s 2. Watch for LOTL tool execution patterns 3. Detect unusual Active Directory queries 4. Flag credential harvesting command sequences
Endpoint-level: 1. Alert on ntdsutil.exe execution 2. Monitor procdump targeting lsass.exe 3. Detect shadow copy deletion 4. Track registry SAM/SYSTEM extraction
The challenge: These look like admin activities. Context is everything.
The Geopolitical Context
These aren't criminal operations. They're military operations conducted in peacetime.
Pre-positioning doctrine: Chinese military doctrine includes cyber pre-positioning - establishing access to critical infrastructure that can be activated during conflict.
• Ability to disrupt US military logistics in Pacific
• Intelligence on Taiwan defense planning
• Economic intelligence from ASEAN
• Telecom access for ongoing surveillance
What this means: The compromise isn't the objective. The access is the objective.
Resources
• [DugganUSA OTX Profile](https://otx.alienvault.com/user/pduggusa) - All pulses
• [STIX Feed](https://analytics.dugganusa.com/api/v1/stix-feed) - Machine-readable
• [CISA Volt Typhoon Advisory](https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-038a)
• [Microsoft Volt Typhoon Analysis](https://www.microsoft.com/en-us/security/blog/2023/05/24/volt-typhoon-targets-us-critical-infrastructure-with-living-off-the-land-techniques/)
*Patrick Duggan is founder of DugganUSA, a Minnesota-based security company. He publishes Typhoon IOCs because (a) Taiwan's 24 million people deserve threat intel too, (b) what hits Taiwan today hits the US tomorrow, and (c) living-off-the-land is genuinely clever tradecraft that deserves documentation.*
*Questions? [email protected]*
The cheapest, fastest, most accurate threat feed on the internet.
275+ enterprises pulling daily. 1M+ IOCs. 17.4M indexed documents. We beat Zscaler by 43 days on NrodeCodeRAT. Starter tier $9/mo — less than any competitor’s sales demo.
Was this useful? Thirty seconds, no cookies, no tracking, no third parties, your address hashed and never stored. If the box below does not load, the same question lives at https://analytics.dugganusa.com/nps.html?post=chinese-apt-typhoon-family-20-iocs-for-volt-salt-flax-and-brass-typhoon
Comments