CVE-2025-30377
📋 TL;DR
This vulnerability is a use-after-free memory corruption flaw in Microsoft Office that allows an attacker to execute arbitrary code on a victim's system. Attackers can exploit this by tricking users into opening a malicious Office document. All users running vulnerable versions of Microsoft Office are affected.
💻 Affected Systems
- Microsoft Office
📦 What is this software?
365 Apps by Microsoft
Excel by Microsoft
Office by Microsoft
Office Long Term Servicing Channel by Microsoft
View all CVEs affecting Office Long Term Servicing Channel →
Office Long Term Servicing Channel by Microsoft
View all CVEs affecting Office Long Term Servicing Channel →
Office Long Term Servicing Channel by Microsoft
View all CVEs affecting Office Long Term Servicing Channel →
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the logged-in user, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Local code execution allowing attackers to install malware, steal credentials, or move laterally within the network.
If Mitigated
Limited impact if proper application sandboxing, least privilege principles, and macro restrictions are enforced.
🎯 Exploit Status
Exploitation requires user interaction to open malicious document. No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific patch versions
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-30377
Restart Required: Yes
Instructions:
1. Open any Office application
2. Go to File > Account > Update Options
3. Select 'Update Now'
4. Restart Office applications when prompted
5. Alternatively, apply through Windows Update or enterprise patch management systems
🔧 Temporary Workarounds
Disable Office macro execution
windowsPrevents malicious macros from executing in Office documents
Set Group Policy: Computer Configuration > Administrative Templates > Microsoft Office 2016 > Security Settings > Trust Center > Disable all macros without notification
Enable Protected View
windowsForces documents from untrusted sources to open in read-only mode
Set Group Policy: Computer Configuration > Administrative Templates > Microsoft Office 2016 > Security Settings > Trust Center > Protected View > Enable Protected View for files originating from the Internet
🧯 If You Can't Patch
- Implement application allowlisting to restrict which Office documents can execute
- Deploy endpoint detection and response (EDR) solutions with behavioral monitoring for Office processes
🔍 How to Verify
Check if Vulnerable:
Check Office version against patched versions in Microsoft Security Update GuideCheck Version:
In Office application: File > Account > About [Application Name]Verify Fix Applied:
Verify Office version matches or exceeds patched version listed in Microsoft advisory📡 Detection & Monitoring
Log Indicators:
- Office application crashes with memory access violations
- Unusual child processes spawned from Office applications
- Suspicious Office document openings from unusual locations
Network Indicators:
- Office applications making unexpected outbound connections after document opening
- DNS requests to suspicious domains following Office document access
SIEM Query:
EventID=1 OR EventID=4688 | where ParentImage contains "winword.exe" OR ParentImage contains "excel.exe" OR ParentImage contains "powerpnt.exe" | where CommandLine contains suspicious patterns