CVE-2021-30927
📋 TL;DR
This CVE describes a use-after-free vulnerability in Apple operating systems that allows an application to execute arbitrary code with kernel privileges. Attackers could gain complete control over affected devices. All users of vulnerable Apple operating systems are affected.
💻 Affected Systems
- macOS
- iOS
- iPadOS
- tvOS
- watchOS
📦 What is this software?
Ipados by Apple
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 →Tvos by Apple
Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with kernel-level privileges, allowing attackers to install persistent malware, steal all data, and control the device entirely.
Likely Case
Privilege escalation from a malicious application to kernel-level access, enabling data theft, surveillance, and system manipulation.
If Mitigated
Limited impact if systems are fully patched and have application sandboxing/enhanced security features enabled.
🎯 Exploit Status
Exploitation requires a malicious application to be installed and executed on the target device. No known public exploits available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.6.2, macOS Monterey 12.1, Security Update 2021-008 Catalina, iOS 15.2, iPadOS 15.2, tvOS 15.2, watchOS 8.3
Vendor Advisory: https://support.apple.com/en-us/HT212975
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Click 'Update Now' if updates are available. 3. Follow on-screen instructions to download and install. 4. Restart device when prompted.
🔧 Temporary Workarounds
Application Restriction
allRestrict installation of untrusted applications to reduce attack surface
For macOS: sudo spctl --master-enable
For iOS/iPadOS: Settings > General > Device Management > Enable restrictions
🧯 If You Can't Patch
- Isolate affected devices from critical networks and sensitive data
- Implement strict application allowlisting and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check current OS version against affected versions listCheck Version:
For macOS: sw_vers -productVersion, For iOS/iPadOS: Settings > General > About > VersionVerify Fix Applied:
Verify OS version matches or exceeds patched versions listed in fix_official section📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Unexpected privilege escalation attempts
- Suspicious application behavior
Network Indicators:
- Unusual outbound connections from system processes
- Command and control traffic from kernel-level processes
SIEM Query:
source="apple_system_logs" AND (event_type="kernel_panic" OR process_privilege="root" AND process_parent="user_app")🔗 References
- https://support.apple.com/en-us/HT212975
- https://support.apple.com/en-us/HT212976
- https://support.apple.com/en-us/HT212978
- https://support.apple.com/en-us/HT212979
- https://support.apple.com/en-us/HT212980
- https://support.apple.com/en-us/HT212981
- https://support.apple.com/en-us/HT212975
- https://support.apple.com/en-us/HT212976
- https://support.apple.com/en-us/HT212978
- https://support.apple.com/en-us/HT212979
- https://support.apple.com/en-us/HT212980
- https://support.apple.com/en-us/HT212981
