CVE-2025-30379
📋 TL;DR
This vulnerability in Microsoft Office Excel involves the release of an invalid pointer or reference, which could allow an attacker to execute arbitrary code on a local system. It affects users who open malicious Excel files. The attacker must trick a user into opening a specially crafted document.
💻 Affected Systems
- Microsoft Office Excel
📦 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 lateral movement.
Likely Case
Local code execution with user-level privileges, allowing file access, credential harvesting, or installation of additional malware.
If Mitigated
No impact if users avoid opening untrusted Excel files and proper security controls are in place.
🎯 Exploit Status
Exploitation requires user interaction and likely involves memory corruption techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft's security update for specific version numbers.
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-30379
Restart Required: Yes
Instructions:
1. Open Microsoft Office application. 2. Go to File > Account > Update Options > Update Now. 3. Follow prompts to install updates. 4. Restart system if required.
🔧 Temporary Workarounds
Block Excel file execution from untrusted sources
windowsConfigure Group Policy or security software to block Excel files from untrusted locations.
Use Microsoft Office Protected View
allEnsure Protected View is enabled for files from the internet.
🧯 If You Can't Patch
- Restrict user permissions to limit damage from code execution.
- Implement application whitelisting to block unauthorized executables.
🔍 How to Verify
Check if Vulnerable:
Check Excel version against patched versions in Microsoft advisory.Check Version:
In Excel: File > Account > About ExcelVerify Fix Applied:
Verify Excel version matches or exceeds patched version listed in Microsoft update.📡 Detection & Monitoring
Log Indicators:
- Unusual Excel process crashes
- Suspicious child processes spawned from Excel
Network Indicators:
- Outbound connections from Excel to unknown IPs post-file open
SIEM Query:
Process creation where parent process is EXCEL.EXE and command line contains unusual parameters