CVE-2021-30916
📋 TL;DR
CVE-2021-30916 is a memory corruption vulnerability in Apple operating systems that allows malicious applications to execute arbitrary code with kernel privileges. This affects iOS, iPadOS, and macOS systems running vulnerable versions. Successful exploitation gives attackers complete control over the affected device.
💻 Affected Systems
- iOS
- iPadOS
- macOS
📦 What is this software?
Ipad Os by Apple
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 persistence, data theft, and ability to bypass all security controls.
Likely Case
Malicious app gains full system access, installs backdoors, steals credentials and sensitive data.
If Mitigated
Limited impact if systems are patched, app sandboxing is enforced, and only trusted apps are installed.
🎯 Exploit Status
Exploitation requires user to install and run a malicious application. Public disclosures include technical details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 15.1, iPadOS 15.1, macOS Monterey 12.0.1, iOS 14.8.1, iPadOS 14.8.1, Security Update 2021-007 Catalina, macOS Big Sur 11.6.1
Vendor Advisory: https://support.apple.com/en-us/HT212867
Restart Required: Yes
Instructions:
1. Open Settings > General > Software Update on iOS/iPadOS or System Preferences > Software Update on macOS. 2. Download and install the latest available update. 3. Restart the device when prompted.
🔧 Temporary Workarounds
Restrict App Installation
allOnly allow installation of apps from trusted sources like the App Store
For iOS/iPadOS: Settings > General > Device Management > Enable restrictions
For macOS: System Preferences > Security & Privacy > Allow apps downloaded from: App Store
🧯 If You Can't Patch
- Implement strict application allowlisting policies
- Segment vulnerable devices from critical network resources
🔍 How to Verify
Check if Vulnerable:
Check current OS version against affected versions listCheck Version:
iOS/iPadOS: Settings > General > About > Version; macOS: Apple menu > About This Mac > macOS versionVerify Fix Applied:
Verify OS version matches or exceeds patched versions listed in fix_official.patch_version📡 Detection & Monitoring
Log Indicators:
- Unexpected kernel extensions loading
- Unusual process spawning with elevated privileges
- System integrity protection (SIP) violations
Network Indicators:
- Unusual outbound connections from system processes
- DNS queries to suspicious domains from kernel processes
SIEM Query:
source="apple_system_logs" AND (event="kernel_extension_load" OR process="kernel_task") AND NOT signature="apple_signed"🔗 References
- http://seclists.org/fulldisclosure/2021/Dec/43
- http://seclists.org/fulldisclosure/2021/Dec/44
- https://support.apple.com/en-us/HT212867
- https://support.apple.com/en-us/HT212868
- https://support.apple.com/en-us/HT212869
- https://support.apple.com/en-us/HT212871
- https://support.apple.com/en-us/HT212872
- https://support.apple.com/kb/HT212975
- https://support.apple.com/kb/HT212980
- http://seclists.org/fulldisclosure/2021/Dec/43
- http://seclists.org/fulldisclosure/2021/Dec/44
- https://support.apple.com/en-us/HT212867
- https://support.apple.com/en-us/HT212868
- https://support.apple.com/en-us/HT212869
- https://support.apple.com/en-us/HT212871
- https://support.apple.com/en-us/HT212872
- https://support.apple.com/kb/HT212975
- https://support.apple.com/kb/HT212980
