Urgent Microsoft Security Update: SharePoint Vulnerabilities Actively Exploited
Tuesday 5th August 2025
Microsoft has issued a critical alert regarding active exploitation of vulnerabilities in on-premises SharePoint servers, specifically CVE-2025-49706 (spoofing) and CVE-2025-49704 (remote code execution). These flaws have now evolved into CVE-2025-53770 and CVE-2025-53771, which are being weaponized by multiple threat actors—including nation-state groups—to deploy ransomware and gain unauthorised access to sensitive systems.
For more detail on this and the full blog by the Microsoft Threat Intelligence, please visit here.
What You Need to Know
- Only on-premises SharePoint servers are affected. SharePoint Online (Microsoft 365) is not impacted.
- Attackers are exploiting these vulnerabilities to bypass authentication and execute malicious code remotely.
- Microsoft has observed Storm-2603, a China-based threat actor, using these exploits to deploy Warlock ransomware.
- Immediate action is required: Microsoft has released comprehensive security updates for SharePoint Server Subscription Edition, 2019, and 2016.
Recommended Mitigations
To protect your environment, Microsoft advises:
- Applying the July 2025 security updates without delay.
- Enabling Antimalware Scan Interface (AMSI) in Full Mode.
- Deploying Microsoft Defender Antivirus and Microsoft Defender for Endpoint.
- Rotating ASP.NET machine keys and restarting IIS services.
How Bytes Can Help
At Bytes, we understand the urgency and complexity of securing your Microsoft environment. As a Microsoft Solutions Partner, we bring deep expertise across key security domains:
|
Designation |
What It Means for You |
|
Threat Protection |
Proven success deploying Microsoft Defender and Sentinel to detect and respond to threats. |
|
Identity & Access Management |
Ensures only the right people access the right resources—securely and efficiently. |
|
Information Protection & Governance |
Helps safeguard sensitive data and meet compliance requirements. |
|
Cloud Security |
Secures your Azure, hybrid, and multi-cloud environments with confidence. |
We’re passionate about helping organisations achieve robust cyber security. Whether you're patching vulnerabilities or planning a long-term security strategy, turn to Bytes as your trusted advisor, and the leading choice for managed Microsoft Security solutions.
If you're running on-premises SharePoint servers, don't wait. Reach out to Bytes today to:
- Assess your exposure
- Apply critical updates
- Strengthen your security posture with Microsoft’s latest tools
Let us be your trusted advisor in navigating today’s evolving threat landscape - get in touch at [email protected].
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