Critical SharePoint Vulnerability Under Global Exploitation: What You Need to Know
A severe security flaw in Microsoft SharePoint is currently being actively exploited worldwide, putting organizations running on-premises servers at significant risk. This vulnerability, designated CVE-2025-53770, boasts a critical severity rating of 9.8 out of 10,indicating its potential for widespread damage. It grants unauthenticated remote access, meaning attackers don’t need credentials to compromise your systems.
Here’s a breakdown of what you need to understand and do:
What’s Happening?
Researchers began observing active exploitation of this zero-day vulnerability on Friday.
The flaw specifically impacts SharePoint Servers that you manage in your own infrastructure.
Importantly, cloud-based SharePoint Online and Microsoft 365 are not affected by this particular vulnerability.
Attackers are not only exploiting the vulnerability for initial access, but are also leveraging it to steal authentication credentials, compounding the risk.
why is This So Serious?
The high severity score reflects the ease with which attackers can exploit this flaw. Unauthenticated access means anyone on the internet can potentially target vulnerable servers. The credential theft aspect is especially concerning, as it allows attackers to move laterally within your network and access sensitive data. This is a complex situation, and requires immediate attention.
What should You Do Now?
Microsoft has released patching instructions, which are available here. Though, simply applying the patch isn’t enough.
Here’s a extensive action plan:
- Apply the Patch Promptly: Prioritize patching all affected SharePoint Servers without delay.
- Credential Review: Assume compromise and thoroughly review your authentication logs for suspicious activity.
- Investigate for Breach: Actively hunt for signs of intrusion within your network. Look for unusual file access, account activity, or network traffic.
- Monitor Closely: Continue to monitor your systems for any further signs of compromise even after patching.
- Stay Informed: Keep up-to-date with the latest details from security sources.
Additional Resources:
CISA Advisory: The Cybersecurity and Infrastructure Security Agency (CISA) has published an alert with further details and guidance: https://www.cisa.gov/news-events/alerts/2025/07/20/update-microsoft-releases-guidance-exploitation-sharepoint-vulnerabilities
Unit42 (Palo Alto Networks): A detailed analysis of the vulnerability and exploitation: https://unit42.paloaltonetworks.com/microsoft-sharepoint-cve-2025-49704-cve-2025-49706-cve-2025-53770
* Akamai Security Research: Technical details, detection methods, and mitigation strategies: [https://www.akamai.com/blog/security-research/sharepoint-vulnerability-rce-active-exploitation-detections-mitigations](https://www.akamai.com/blog/security-research/sharepoint-v