In a disturbing development that has sent shockwaves through the cybersecurity world, both Google and Microsoft have confirmed that Chinese state backed hackers are actively exploiting a newly discovered SharePoint zero day vulnerability. The threat identified as CVE 2025-53770 poses a significant risk to organizations worldwide that rely on Microsoft’s SharePoint platform for internal communications and document sharing.
Security experts warn that this zero day flaw enables hackers to steal sensitive private keys, inject malware, and compromise entire enterprise networks. As enterprises scramble to patch their systems, the incident underscores the growing threat of state sponsored cyberattacks and the urgent need for robust digital defense strategies.
What Is the SharePoint Zero Day Vulnerability?
The SharePoint zero day vulnerability (CVE-2025-53770) was discovered over the past weekend. It impacts self hosted versions of Microsoft SharePoint a widely used document management and collaboration tool utilized by thousands of organizations globally, from small businesses to government agencies.
According to Microsoft’s threat intelligence team, the flaw allows remote code execution and, more alarmingly, grants attackers access to sensitive private encryption keys. Once inside the system, hackers can deploy custom malware, exfiltrate confidential data, and pivot to other critical systems within the network.
Google and Microsoft Confirm State Backed Exploitation
Both Google’s Mandiant team and Microsoft’s Threat Intelligence Center have traced the attacks back to a known Chinese threat group, which has a history of exploiting software vulnerabilities for cyber espionage purposes.
John Hultquist, Chief Analyst at Mandiant (now part of Google Cloud), stated. “We’ve observed targeted exploitation consistent with the tactics and infrastructure of Chinese nation state actors. This campaign is more sophisticated and dangerous than typical criminal hacks. It’s espionage at the highest level.”
Microsoft echoed similar concerns, noting that the attack method demonstrated a clear understanding of SharePoint’s architecture and internal certificate handling mechanisms. They emphasized that “patching alone may not be enough if attackers have already stolen cryptographic material.”
How the Exploit Works
At the technical level, the vulnerability lies in how SharePoint authenticates internal users through encrypted keys. Hackers use a specially crafted payload to extract these keys from the server memory. Once obtained, the attacker can masquerade as a trusted user, bypassing all traditional security measures.
Alex Stamos, former Facebook CSO and cybersecurity professor at Stanford, explained. “This is a devastating vector. Once you hold the private key, you’re no longer an outsider trying to break in you’re an insider. That’s what makes the SharePoint zero-day particularly catastrophic.”
Real World Impact: Case Study of a Targeted U.S Law Firm
One of the early confirmed victims is a mid sized U.S. law firm specializing in intellectual property, which unknowingly hosted an unpatched version of SharePoint. Within hours of the exploit being used, attackers had accessed sensitive case files, internal communications, and financial records.
The firm’s CTO, who asked not to be named, shared their experience. “We were blind. No alerts were triggered. We only noticed after unusual logins from unfamiliar IPs. By then, the damage was done.”
Forensics revealed that malware had been deployed across the network, with lateral movement detected toward financial systems. The breach is now under federal investigation.
What Can Organizations Do?
In light of the active exploitation of the SharePoint zero day, security professionals are urging organizations to take immediate action.
1. Patch Immediately: Microsoft has released emergency patches. These should be applied across all instances of self hosted SharePoint.
2. Revoke and Rotate Keys: Since attackers may have accessed private keys, rotate all relevant certificates and encryption credentials.
3. Conduct Full System Audits: Look for signs of unauthorized access, suspicious file transfers, or malware presence.
4. Limit SharePoint Exposure: Where possible, restrict SharePoint to internal networks and disable remote access.
5. Implement Behavior Based Detection: Signature based tools may miss sophisticated attacks. Invest in solutions that analyze anomalies in user behavior.
The Bigger Picture: Cyberwarfare and Digital Espionage
The SharePoint zero day incident is not isolated. It fits a broader trend of state sponsored cyberattacks, particularly from Chinese APT (Advanced Persistent Threat) groups targeting intellectual property, infrastructure, and defense contractors.
Eva Galperin, Director of Cybersecurity at EFF, says. “China’s strategy is long term. They’re not just looking for immediate disruption they’re building dossiers, collecting information that may be useful a decade from now.”
This adds a national security dimension to what may appear to be a corporate cybersecurity issue. As more critical infrastructure shifts to digital platforms, such vulnerabilities become frontline battlegrounds in geopolitical power struggles.
A Wake Up Call for the Global Enterprise Community
This incident should serve as a wake up call. Organizations regardless of size or sector must assume they are potential targets in a global cyber conflict. Securing collaborative tools like SharePoint is no longer just an IT task; it’s a business imperative and a matter of national resilience.
While patching the current SharePoint zero day is vital, the larger challenge lies in rethinking how we approach digital security in a world where software supply chains, insider threats, and zero day exploits have become everyday realities.
Resilience Beyond Patching
The exploitation of this SharePoint zero day by Chinese backed hackers once again highlights a harsh truth even the most trusted platforms can become liabilities if not actively secured and monitored. The sophistication of state actors demands an equally advanced response one rooted in vigilance, transparency, and a culture of cybersecurity at every level of the organization.