CVE-2021-30955
📋 TL;DR
This CVE describes a race condition vulnerability in Apple operating systems that allows malicious applications to execute arbitrary code with kernel privileges. It affects macOS, iOS, iPadOS, tvOS, and watchOS before specific patch versions. Attackers could gain complete control over affected devices.
💻 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 →Tvos by Apple
Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with kernel-level access, allowing attackers to install persistent malware, steal sensitive data, or create backdoors.
Likely Case
Malicious apps from untrusted sources could gain elevated privileges to bypass security controls and access protected system resources.
If Mitigated
With proper app vetting and security controls, exploitation risk is significantly reduced, though the vulnerability still exists in unpatched systems.
🎯 Exploit Status
Exploitation requires a malicious application to be installed and executed on the target device. Race conditions can be challenging to exploit reliably.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Monterey 12.1, 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 Settings/System Preferences. 2. Navigate to Software Update. 3. Download and install the latest available update. 4. Restart the device when prompted.
🔧 Temporary Workarounds
Application Restriction
allRestrict installation of applications from untrusted sources to prevent malicious apps from being installed.
🧯 If You Can't Patch
- Implement strict application allowlisting policies
- Deploy endpoint detection and response (EDR) solutions to monitor for suspicious kernel-level activity
🔍 How to Verify
Check if Vulnerable:
Check the operating system version against affected versions. For macOS: System Preferences > About This Mac. For iOS/iPadOS: Settings > General > About.Check Version:
macOS: sw_vers -productVersion; iOS/iPadOS: Settings > General > About > VersionVerify Fix Applied:
Verify the operating system version matches or exceeds the patched versions listed in the fix information.📡 Detection & Monitoring
Log Indicators:
- Unexpected kernel extensions loading
- Suspicious privilege escalation attempts
- Unusual application behavior with kernel access
Network Indicators:
- Communication with known malicious domains after privilege escalation
- Unexpected outbound connections from system processes
SIEM Query:
Process creation events where parent process is user application and child process has SYSTEM/KERNEL privileges🔗 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/HT212980
- 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/HT212980
