AMSI

CISA Urges Immediate Patching as Multiple SharePoint Server Vulnerabilities Confirmed Exploited

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has issued an urgent advisory after confirming active exploitation of multiple vulnerabilities in Microsoft SharePoint Server. Four specific CVEs have been added to the Known Exploited Vulnerabilities (KEV) catalog, with one additional flaw flagged by Microsoft as high-risk even without confirmed exploitation. Successful attacks can lead to remote code execution, theft of Internet Information Services (IIS) machine keys, establishment of persistent access, and deployment of malware. CISA recommends applying the latest Microsoft patches immediately, verifying successful installation, enabling the Antimalware Scan Interface (AMSI), and strengthening monitoring through Microsoft Defender Antivirus. Organizations are also advised to avoid direct internet exposure of SharePoint servers and to implement Layer 7 reverse proxies with enhanced logging to reduce the attack surface.