CVE-2021-1779
📋 TL;DR
This vulnerability allows malicious applications to execute arbitrary code with system privileges on macOS systems due to a logic error in kernel extension (kext) loading. It affects macOS Big Sur, Catalina, and Mojave before specific security updates. Attackers could gain full control of affected systems.
💻 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
Complete system compromise with root-level access, allowing installation of persistent malware, data theft, and lateral movement across networks.
Likely Case
Privilege escalation from user-level to system-level access, enabling attackers to bypass security controls and maintain persistence.
If Mitigated
Limited impact if systems are fully patched and running with minimal user privileges, though initial compromise could still occur.
🎯 Exploit Status
Requires local access and ability to run malicious applications. The logic error in kext loading state handling must be triggered.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave
Vendor Advisory: https://support.apple.com/en-us/HT212147
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install available updates. 3. Restart when prompted. For enterprise: Deploy updates via MDM or management tools.
🔧 Temporary Workarounds
Disable kernel extension loading
macOSPrevent loading of unsigned or unauthorized kernel extensions
sudo spctl kext-consent disable
sudo nvram boot-args="kext-dev-mode=0"
🧯 If You Can't Patch
- Restrict user privileges and application execution to trusted sources only
- Implement application allowlisting and monitor for unauthorized kext loading attempts
🔍 How to Verify
Check if Vulnerable:
Check macOS version: Big Sur < 11.2, Catalina without 2021-001 update, Mojave without 2021-001 updateCheck Version:
sw_versVerify Fix Applied:
Verify macOS version is Big Sur 11.2 or later, or Catalina/Mojave with Security Update 2021-001 installed📡 Detection & Monitoring
Log Indicators:
- Unauthorized kernel extension loading in system.log
- Suspicious kext-related processes
Network Indicators:
- Unusual outbound connections from system processes
SIEM Query:
source="system.log" AND "kext" AND ("load" OR "unload")