CVE-2024-43465
📋 TL;DR
This vulnerability in Microsoft Excel allows an attacker to gain elevated privileges by exploiting a use-after-free memory issue (CWE-416). Attackers could execute arbitrary code with the privileges of the current user by tricking them into opening a specially crafted Excel file. This affects users running vulnerable versions of Microsoft Excel.
💻 Affected Systems
- Microsoft Excel
📦 What is this software?
365 Apps by Microsoft
365 Apps by Microsoft
Excel by Microsoft
Excel by Microsoft
Office 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 through arbitrary code execution with user privileges, potentially leading to data theft, ransomware deployment, or lateral movement within networks.
Likely Case
Local privilege escalation allowing attackers to install programs, modify data, or create new accounts with user rights after initial access.
If Mitigated
Limited impact if users operate with minimal privileges, macros are disabled, and files are opened in Protected View.
🎯 Exploit Status
Requires user interaction (opening malicious file); exploitation depends on bypassing memory protections.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Latest security updates from Microsoft
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-43465
Restart Required: Yes
Instructions:
1. Open Excel. 2. Go to File > Account > Update Options > Update Now. 3. Alternatively, use Windows Update for system-wide Office updates. 4. Restart computer if prompted.
🔧 Temporary Workarounds
Disable automatic opening of Excel files
windowsConfigure Excel to open files in Protected View by default to prevent automatic code execution.
Not applicable - configure via Excel Trust Center settings
Block suspicious Excel file types
allUse email filtering and endpoint protection to block .xlsm and .xlsb files from untrusted sources.
🧯 If You Can't Patch
- Run Excel with minimal user privileges (not as administrator)
- Disable macros and ActiveX controls in Excel Trust Center settings
🔍 How to Verify
Check if Vulnerable:
Check Excel version against patched versions in Microsoft advisory; unpatched versions are vulnerable.Check Version:
In Excel: File > Account > About Excel (Windows) or Excel > About Excel (macOS)Verify Fix Applied:
Verify Excel has updated to latest version via File > Account > About Excel.📡 Detection & Monitoring
Log Indicators:
- Excel crash logs with memory access violations
- Unexpected Excel processes spawning child processes
Network Indicators:
- Unusual outbound connections from Excel process
SIEM Query:
Process creation where parent_process contains 'excel.exe' and command_line contains unusual parameters