CVE-2024-49027
📋 TL;DR
This vulnerability allows attackers to execute arbitrary code on systems running vulnerable versions of Microsoft Excel by tricking users into opening specially crafted Excel files. It affects users of Microsoft Excel across multiple platforms who open untrusted documents.
💻 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 →
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 within the network.
Likely Case
Local privilege escalation or remote code execution when users open malicious Excel files from email attachments or downloads.
If Mitigated
Limited impact with proper application whitelisting, macro restrictions, and user training preventing malicious file execution.
🎯 Exploit Status
Requires user interaction to open malicious file. No known public exploits as of current information.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Latest security updates from Microsoft
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-49027
Restart Required: Yes
Instructions:
1. Open Excel and go to File > Account > Update Options > Update Now. 2. For enterprise deployments, deploy Microsoft security updates through WSUS or SCCM. 3. Ensure Office Click-to-Run updates are enabled.
🔧 Temporary Workarounds
Block Office file types via email filtering
allConfigure email gateways to block .xls, .xlsx, .xlsm attachments from untrusted sources
Enable Protected View
windowsForce Excel files from internet sources to open in Protected View
File > Options > Trust Center > Trust Center Settings > Protected View > Enable all options
🧯 If You Can't Patch
- Implement application whitelisting to block unauthorized Excel execution
- Train users to never open Excel files from untrusted sources
🔍 How to Verify
Check if Vulnerable:
Check Excel version against Microsoft Security Update Guide for affected versionsCheck Version:
In Excel: File > Account > About Excel (Windows) or Excel > About Excel (macOS)Verify Fix Applied:
Verify Excel version is updated to latest security patch level📡 Detection & Monitoring
Log Indicators:
- Excel process spawning unexpected child processes
- Excel accessing unusual network resources
- Multiple Excel crash events
Network Indicators:
- Excel.exe making unexpected outbound connections
- DNS requests for suspicious domains from Excel process
SIEM Query:
source="windows" AND process_name="EXCEL.EXE" AND (child_process!="" OR network_connection!="")