Threat actors
Storm-2603
ransomwareCNvia MISP
3 CVEs attributed
Aliases1
Longlegs
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.
Attributed CVEs3
| CVE | Description | Severity | EPSS | Flags | Modified |
|---|---|---|---|---|---|
| CVE-2025-53770 | Deserialization of untrusted data in on-premises Microsoft SharePoint Server allows an unauthorized attacker to execute code over a network. Microsoft is aware that an exploit for CVE-2025-53770 exists in the wild. Microsoft is preparing and fully testing a comprehensive update to address this vulnerability. In the meantime, please make sure that the mitigation provided in this CVE documentation is in place so that you are protected from exploitation. | CRITICAL9.8 | 100%p100 | KEV+RWeaponized | 2026-08-04 |
| CVE-2025-49704 | Improper control of generation of code ('code injection') in Microsoft Office SharePoint allows an authorized attacker to execute code over a network. | HIGH8.8 | 100%p100 | KEV+RWeaponized | 2026-06-17 |
| CVE-2025-49706 | Improper authentication in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network. | MEDIUM6.5 | 99%p100 | KEV+RWeaponized | 2026-08-04 |