CVE-2020-9841
📋 TL;DR
This CVE describes an integer overflow vulnerability in macOS that allows an application to execute arbitrary code with kernel privileges. It affects macOS systems before version 10.15.5. Successful exploitation gives attackers complete control over the affected system.
💻 Affected Systems
- macOS
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with kernel-level privileges, allowing attackers to install persistent malware, steal sensitive data, or use the system as a foothold for lateral movement.
Likely Case
Local privilege escalation where a malicious application gains kernel privileges to bypass security controls and perform unauthorized actions.
If Mitigated
Limited impact if systems are fully patched, applications are from trusted sources, and proper endpoint protection is in place.
🎯 Exploit Status
Requires local application execution. No public exploit code has been disclosed as of knowledge cutoff.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Catalina 10.15.5 or later
Vendor Advisory: https://support.apple.com/HT211170
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install macOS Catalina 10.15.5 update. 3. Restart the system when prompted.
🔧 Temporary Workarounds
Application Restriction
allRestrict installation and execution of untrusted applications
sudo spctl --master-enable
sudo spctl --enable --label "Developer ID"
🧯 If You Can't Patch
- Implement application allowlisting to prevent execution of untrusted applications
- Use endpoint detection and response (EDR) solutions to monitor for privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check macOS version: if version is earlier than 10.15.5, system is vulnerableCheck Version:
sw_versVerify Fix Applied:
Verify macOS version is 10.15.5 or later and security update 2020-003 is installed📡 Detection & Monitoring
Log Indicators:
- Unexpected kernel extensions loading
- Processes running with unexpected privileges
- System integrity protection (SIP) violations
Network Indicators:
- Outbound connections from kernel processes
- Unusual network activity following local privilege escalation
SIEM Query:
process where parent_process_name contains "kernel" and process_name not in (expected_kernel_processes)