CVE-2024-30042
📋 TL;DR
This vulnerability allows remote code execution through specially crafted Excel files. Attackers can exploit this by tricking users into opening malicious documents, potentially gaining full control of the affected system. All users running vulnerable versions of Microsoft Excel are affected.
💻 Affected Systems
- Microsoft 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 →
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining administrative privileges, data exfiltration, ransomware deployment, and lateral movement within the network.
Likely Case
Local user account compromise leading to data theft, credential harvesting, and installation of persistent malware.
If Mitigated
Limited impact due to application sandboxing, restricted user permissions, and network segmentation preventing lateral movement.
🎯 Exploit Status
Exploitation requires user interaction to open malicious file. No public exploit code available at time of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Latest security updates from Microsoft
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-30042
Restart Required: Yes
Instructions:
1. Open Microsoft Excel. 2. Go to File > Account > Update Options > Update Now. 3. Install all available updates. 4. Restart computer if prompted.
🔧 Temporary Workarounds
Disable automatic opening of Excel files
windowsPrevents automatic execution of malicious Excel files from email or web downloads
Set Outlook to disable automatic preview of attachments
Configure Windows to open Excel files in Protected View
Use Microsoft Office File Block policy
windowsBlocks opening of specific Excel file types that could be malicious
Configure via Group Policy: Computer Configuration > Administrative Templates > Microsoft Office 2016 > Security Settings > File Block
🧯 If You Can't Patch
- Implement application whitelisting to block unauthorized Excel execution
- Deploy network segmentation to isolate Excel users from critical systems
🔍 How to Verify
Check if Vulnerable:
Check Excel version against Microsoft Security Update Guide for CVE-2024-30042Check Version:
In Excel: File > Account > About ExcelVerify Fix Applied:
Verify Excel version is updated to latest security patch version📡 Detection & Monitoring
Log Indicators:
- Unusual Excel process spawning child processes
- Excel accessing network resources unexpectedly
- Multiple failed Excel file openings
Network Indicators:
- Excel process making unexpected outbound connections
- DNS queries to suspicious domains from Excel process
SIEM Query:
Process Creation where Parent Process contains 'excel.exe' AND (Command Line contains 'powershell' OR Command Line contains 'cmd' OR Command Line contains 'wscript')