CVE-2021-30736
📋 TL;DR
This is a kernel-level buffer overflow vulnerability in Apple operating systems that allows malicious applications to execute arbitrary code with kernel privileges. It affects macOS, iOS, iPadOS, tvOS, and watchOS. Successful exploitation gives attackers 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 persistence, data theft, and ability to bypass all security controls.
Likely Case
Malicious app gains full system access, installs backdoors, and steals sensitive data.
If Mitigated
Limited to sandboxed app compromise if proper app vetting and isolation are in place.
🎯 Exploit Status
Requires user to install/execute malicious application. No public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.4, tvOS 14.6, watchOS 7.5, iOS 14.6, iPadOS 14.6
Vendor Advisory: https://support.apple.com/en-us/HT212528
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install available updates. 3. Restart device when prompted.
🔧 Temporary Workarounds
Application Restriction
allRestrict installation of untrusted applications to prevent exploitation.
🧯 If You Can't Patch
- Implement strict application allowlisting to prevent untrusted app execution.
- Isolate vulnerable devices from critical networks and data.
🔍 How to Verify
Check if Vulnerable:
Check OS version in System Preferences > About This Mac (macOS) or Settings > General > About (iOS/iPadOS).Check Version:
sw_vers (macOS) or Settings > General > About > Version (iOS/iPadOS)Verify Fix Applied:
Verify OS version is equal to or newer than patched versions listed above.📡 Detection & Monitoring
Log Indicators:
- Unexpected kernel panics
- Suspicious application installations
- Unusual privilege escalation attempts
Network Indicators:
- Unusual outbound connections from system processes
- Command and control traffic from kernel space
SIEM Query:
source="kernel" AND (event="panic" OR event="buffer_overflow")🔗 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/HT212528
- https://support.apple.com/en-us/HT212529
- https://support.apple.com/en-us/HT212532
- https://support.apple.com/en-us/HT212533
