CVE-2021-30703
📋 TL;DR
This CVE describes a double free vulnerability in Apple operating systems that allows an application to execute arbitrary code with kernel privileges. It affects multiple Apple platforms including iOS, iPadOS, tvOS, watchOS, and macOS. Successful exploitation gives attackers complete control over affected devices.
💻 Affected Systems
- iOS
- iPadOS
- tvOS
- watchOS
- macOS
📦 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 privileges, allowing attackers to install persistent malware, steal sensitive data, or create backdoors.
Likely Case
Local privilege escalation where a malicious app gains kernel privileges to bypass security controls and access protected system resources.
If Mitigated
Limited impact with proper app sandboxing and security controls preventing malicious app installation.
🎯 Exploit Status
Requires local access or ability to install malicious application. No public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: tvOS 14.6, iOS 14.6, iPadOS 14.6, Security Update 2021-004 Catalina, Security Update 2021-005 Mojave, macOS Big Sur 11.4, watchOS 7.5
Vendor Advisory: https://support.apple.com/en-us/HT212528
Restart Required: Yes
Instructions:
1. Open Settings app. 2. Go to General > Software Update. 3. Download and install the latest available update. 4. Restart device when prompted.
🔧 Temporary Workarounds
Restrict App Installation
allOnly allow installation of apps from trusted sources like the App Store
Enable Full Disk Encryption
allProtect data at rest in case of compromise
🧯 If You Can't Patch
- Isolate affected devices from critical networks and sensitive data
- Implement strict application allowlisting policies
🔍 How to Verify
Check if Vulnerable:
Check OS version in Settings > General > About on iOS/iPadOS, or About This Mac on macOSCheck Version:
sw_vers (macOS) or Settings > General > About > Version (iOS/iPadOS)Verify Fix Applied:
Verify OS version matches or exceeds patched versions listed in fix_official.patch_version📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Unexpected process privilege escalation
- Memory corruption crash reports
Network Indicators:
- Unusual outbound connections from system processes
- Suspicious network activity from kernel-level processes
SIEM Query:
Process creation events where parent process is kernel or system-level process with unusual command line arguments🔗 References
- https://support.apple.com/en-us/HT212528
- https://support.apple.com/en-us/HT212529
- https://support.apple.com/en-us/HT212532
- https://support.apple.com/en-us/HT212533
- https://support.apple.com/en-us/HT212600
- https://support.apple.com/en-us/HT212603
- https://support.apple.com/en-us/HT212528
- https://support.apple.com/en-us/HT212529
- https://support.apple.com/en-us/HT212532
- https://support.apple.com/en-us/HT212533
- https://support.apple.com/en-us/HT212600
- https://support.apple.com/en-us/HT212603
