Threat Actor 🇨🇳 China

Storm-2603

The group Microsoft tracks as Storm-2603 is assessed with medium confidence to be a China-based threat actor. Microsoft has not identified links between Storm-2603 and other known Chinese threat actors. Microsoft tracks this threat actor in association with attempts to steal MachineKeys via the on-premises SharePoint vulnerabilities. Although Microsoft has observed this threat actor deploying Warlock and Lockbit ransomware in the past, Microsoft is currently unable to confidently assess the threat actor’s objectives. Additional actors may use these exploits to target unpatched on-premises SharePoint systems, further emphasizing the need for organizations to implement mitigations and security updates immediately.

Indicators of Compromise 20

MITRE ATT&CK TTPs 34

Source Articles

IR Trends Q2 2026: Phishing and weaponized remote management tools drive attack chains
In Q2 2026, phishing remained the dominant initial access vector, accounting for over half of incident response engagements, with attackers increasingly leveraging QR code-embedded PDFs and trusted cloud platforms to bypass defenses. Threat actors, including the newly observed Sinobi ransomware group and Warlock (Storm-2603), weaponized legitimate remote management tools such as trojanized MeshAgent and Zoho Assist for stealthy persistence and lateral movement. Authentication abuse surged, with adversaries bypassing MFA using adversary-in-the-middle proxies, session token theft, and MFA fatigue attacks. The PhaaS platform ARToken was identified, offering a comprehensive toolkit for Microsoft 365 compromise via OAuth-based phishing, highlighting a growing trend in commoditized, sophisticated access-as-a-service operations.
talos ·6h ago
ToolShell Used to Compromise Telecoms Company in Middle East | SECURITY.COM
China-based threat actors exploited the ToolShell vulnerability (CVE-2025-53770) to compromise a telecoms company in the Middle East and multiple government agencies globally shortly after the patch was released in July 2025. The attackers deployed backdoors such as Zingdoor and ShadowPad, used DLL sideloading techniques, and leveraged tools like KrustyLoader and Sliver for post-exploitation. Activities indicate espionage motives, with credential theft and lateral movement observed across compromised networks.
security.com