CVE-2021-30680
📋 TL;DR
This macOS vulnerability allows a local user to bypass Apple's security policy and load unsigned kernel extensions (KEXTs). This affects macOS systems before Big Sur 11.4. Kernel extensions run with high privileges, so this could enable privilege escalation or system compromise.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
An attacker with local access could load malicious kernel extensions to gain root privileges, install persistent malware, bypass security controls, or compromise the entire system.
Likely Case
Malicious local users or malware with user-level access could escalate privileges to install rootkits, keyloggers, or other kernel-level malware.
If Mitigated
With proper security controls like System Integrity Protection (SIP) enabled and regular patching, the risk is significantly reduced as unsigned KEXTs would be blocked.
🎯 Exploit Status
Requires local access and knowledge of kernel extension development. No public exploit code has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.4
Vendor Advisory: https://support.apple.com/en-us/HT212529
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install macOS Big Sur 11.4 or later. 3. Restart the system when prompted.
🔧 Temporary Workarounds
Enable System Integrity Protection (SIP)
allEnsure SIP is enabled to block unsigned kernel extensions from loading.
csrutil status
Restrict local user privileges
allLimit local user accounts to standard user privileges to reduce attack surface.
🧯 If You Can't Patch
- Ensure System Integrity Protection (SIP) is enabled and not disabled
- Implement strict access controls to limit local user privileges and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check macOS version: if earlier than 11.4, system is vulnerable.Check Version:
sw_versVerify Fix Applied:
Verify macOS version is 11.4 or later and check that System Integrity Protection is enabled.📡 Detection & Monitoring
Log Indicators:
- Kernel extension loading attempts in system logs
- Unauthorized kextload commands in audit logs
Network Indicators:
- None - this is a local privilege escalation vulnerability
SIEM Query:
Search for kextload events or kernel extension loading in macOS system logs