CVE-2020-9967
📋 TL;DR
CVE-2020-9967 is a kernel memory corruption vulnerability in Apple's XNU network stack that allows remote attackers to cause system crashes or corrupt kernel memory through heap overflow. This affects multiple Apple operating systems including macOS, iOS, iPadOS, tvOS, and watchOS. Attackers can potentially achieve remote code execution or denial of service.
💻 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
Remote kernel-level code execution leading to complete system compromise, data theft, and persistent backdoor installation.
Likely Case
Remote denial of service causing system crashes and instability, potentially leading to data loss and service disruption.
If Mitigated
Limited impact with proper network segmentation and firewalls, potentially only affecting exposed services.
🎯 Exploit Status
Public exploit details available via Packet Storm Security. Exploitation requires crafting malicious network packets.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.0.1, tvOS 14.0, macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave, watchOS 7.0, iOS 14.0 and iPadOS 14.0
Vendor Advisory: https://support.apple.com/en-us/HT211843
Restart Required: Yes
Instructions:
1. Go to System Preferences > Software Update. 2. Install all available updates. 3. Restart the system when prompted.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected systems from untrusted networks using firewalls and VLANs.
Disable Unnecessary Services
allTurn off network services not required for operation to reduce attack surface.
🧯 If You Can't Patch
- Implement strict network access controls and firewall rules to limit exposure
- Monitor systems for unusual network activity and crash reports
🔍 How to Verify
Check if Vulnerable:
Check system version against affected versions list. On macOS: sw_vers -productVersionCheck Version:
macOS: sw_vers -productVersion, iOS/iPadOS: Settings > General > About > VersionVerify Fix Applied:
Verify system version is equal to or newer than patched versions listed in fix_official.patch_version📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- System crash reports
- Unexpected system reboots
Network Indicators:
- Malformed network packets to vulnerable ports
- Unusual network traffic patterns
SIEM Query:
source="kernel" AND ("panic" OR "crash") AND dest_ip IN [affected_systems]🔗 References
- http://packetstormsecurity.com/files/163501/XNU-Network-Stack-Kernel-Heap-Overflow.html
- https://support.apple.com/en-us/HT211843
- https://support.apple.com/en-us/HT211844
- https://support.apple.com/en-us/HT211850
- https://support.apple.com/en-us/HT211931
- https://support.apple.com/en-us/HT212011
- http://packetstormsecurity.com/files/163501/XNU-Network-Stack-Kernel-Heap-Overflow.html
- https://support.apple.com/en-us/HT211843
- https://support.apple.com/en-us/HT211844
- https://support.apple.com/en-us/HT211850
- https://support.apple.com/en-us/HT211931
- https://support.apple.com/en-us/HT212011
