CVE-2020-27944
📋 TL;DR
CVE-2020-27944 is a memory corruption vulnerability in Apple's font processing that allows arbitrary code execution when processing malicious font files. This affects multiple Apple operating systems including iOS, macOS, watchOS, and tvOS. Attackers can exploit this by tricking users into opening malicious documents or visiting malicious websites containing crafted fonts.
💻 Affected Systems
- iOS
- iPadOS
- macOS
- watchOS
- tvOS
📦 What is this software?
Ipad Os 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
Full system compromise with attacker gaining root privileges and persistent access to the device.
Likely Case
Malware installation, data theft, or device takeover when users open malicious documents or visit compromised websites.
If Mitigated
Limited impact with proper patch management and user education about suspicious files.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file or visiting malicious website) but no authentication. Memory corruption vulnerabilities in font processing have been weaponized in the past.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 14.3, iPadOS 14.3, macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave, watchOS 7.2, tvOS 14.3
Vendor Advisory: https://support.apple.com/en-us/HT212003
Restart Required: Yes
Instructions:
1. Open Settings/System Preferences. 2. Navigate to Software Update. 3. Install the latest available update. 4. Restart the device when prompted.
🔧 Temporary Workarounds
Disable automatic font installation
allPrevent automatic font processing in web browsers and applications
User education
allTrain users to avoid opening suspicious documents or visiting untrusted websites
🧯 If You Can't Patch
- Implement application whitelisting to prevent execution of unauthorized applications
- Use network segmentation to isolate vulnerable devices from critical systems
🔍 How to Verify
Check if Vulnerable:
Check system version against affected versions list. On macOS: 'sw_vers -productVersion'. On iOS/iPadOS: Settings > General > About > Version.Check Version:
macOS: 'sw_vers -productVersion', iOS/iPadOS: Check in Settings > General > AboutVerify Fix Applied:
Verify system version matches or exceeds patched versions listed in fix_official section.📡 Detection & Monitoring
Log Indicators:
- Unexpected font file processing
- Application crashes related to font libraries
- Unusual process execution following font file access
Network Indicators:
- Downloads of font files from suspicious sources
- Font file transfers in unexpected network traffic
SIEM Query:
Process creation events where parent process is font-related and child process is suspicious (e.g., cmd.exe, bash, powershell)🔗 References
- https://support.apple.com/en-us/HT212003
- https://support.apple.com/en-us/HT212005
- https://support.apple.com/en-us/HT212009
- https://support.apple.com/en-us/HT212011
- https://support.apple.com/en-us/HT212003
- https://support.apple.com/en-us/HT212005
- https://support.apple.com/en-us/HT212009
- https://support.apple.com/en-us/HT212011
