CVE-2021-30824
📋 TL;DR
This is a macOS kernel memory corruption vulnerability that allows malicious applications to execute arbitrary code with kernel privileges. It affects macOS Catalina, Big Sur, and Monterey systems before specific security updates. Successful exploitation gives attackers complete system control.
💻 Affected Systems
- macOS
📦 What is this software?
Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →Macos by Apple
macOS is Apple's desktop and laptop operating system powering Mac computers used by millions of professionals, developers, creative professionals, and enterprise users worldwide. Built on a Unix foundation with the Darwin kernel and modern Cocoa frameworks, macOS delivers a seamless ecosystem integr...
Learn more about Macos →⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with kernel-level persistence, data theft, and backdoor installation
Likely Case
Malicious application gains kernel privileges to bypass security controls and install malware
If Mitigated
Limited impact due to application sandboxing and security controls, but kernel access still dangerous
🎯 Exploit Status
Requires user to execute malicious application; kernel exploitation requires technical sophistication
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Monterey 12.0.1, Security Update 2021-007 Catalina, macOS Big Sur 11.6.1
Vendor Advisory: https://support.apple.com/en-us/HT212869
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install available security updates. 3. Restart when prompted.
🔧 Temporary Workarounds
Application Restriction
macOSRestrict installation and execution of untrusted applications
sudo spctl --master-enable
sudo spctl --enable --label "Developer ID"
🧯 If You Can't Patch
- Implement strict application allowlisting to prevent execution of untrusted software
- Use endpoint detection and response (EDR) tools to monitor for suspicious kernel activity
🔍 How to Verify
Check if Vulnerable:
Check macOS version: sw_vers -productVersion. Vulnerable if: Catalina < 10.15.7 with Security Update 2021-007, Big Sur < 11.6.1, Monterey < 12.0.1Check Version:
sw_vers -productVersionVerify Fix Applied:
Verify version is at or above patched versions: sw_vers -productVersion📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Unexpected kernel extensions loading
- Suspicious process privilege escalation
Network Indicators:
- Not network exploitable - focus on endpoint behavior
SIEM Query:
process where parent_process_name contains "kernel" and process_name not in approved_kernel_processes