CVE-2021-30901
📋 TL;DR
This vulnerability allows malicious applications to write data beyond allocated memory boundaries in macOS kernel components, potentially leading to arbitrary code execution with kernel privileges. It affects macOS Catalina, Big Sur, and Monterey systems before specific security updates. Attackers could gain 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
Full system compromise with kernel-level privileges, allowing installation of persistent malware, data theft, and complete control over the affected system.
Likely Case
Malicious application gains kernel privileges to bypass security controls, install backdoors, or perform privilege escalation attacks.
If Mitigated
With proper application sandboxing and security controls, impact limited to application-level compromise rather than full system takeover.
🎯 Exploit Status
Exploitation requires user to install and run malicious application. No public exploit code available as of analysis.
🛠️ 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 system when prompted.
🔧 Temporary Workarounds
Application Restriction
allRestrict installation of untrusted applications via Gatekeeper and System Integrity Protection
sudo spctl --master-enable
sudo csrutil enable
🧯 If You Can't Patch
- Implement strict application allowlisting to prevent installation of untrusted software
- Enable full disk encryption and monitor for suspicious kernel activity
🔍 How to Verify
Check if Vulnerable:
Check macOS version: System Preferences > About This MacCheck Version:
sw_versVerify Fix Applied:
Verify installed security update in System Preferences > Software Update > Installed Updates📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Unexpected kernel extensions loading
- Suspicious application installation events
Network Indicators:
- Unusual outbound connections from kernel processes
SIEM Query:
source="macos" AND (event_type="kernel_panic" OR process_name="kernel_task" AND action="suspicious")