CVE-2021-1880
📋 TL;DR
CVE-2021-1880 is a memory corruption vulnerability in Apple's image processing that allows arbitrary code execution when processing malicious images. It affects macOS and watchOS users running vulnerable versions. Successful exploitation could give attackers full control of affected devices.
💻 Affected Systems
- macOS
- watchOS
📦 What is this software?
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 →Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining root privileges, installing persistent malware, and accessing all user data.
Likely Case
Local privilege escalation or remote code execution when user opens a malicious image file, potentially leading to data theft or ransomware deployment.
If Mitigated
Limited impact with proper patch management and user education about opening untrusted files.
🎯 Exploit Status
Exploitation requires user interaction to process malicious image but no authentication needed. No public exploit code known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.3, watchOS 7.4
Vendor Advisory: https://support.apple.com/en-us/HT212324
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install macOS Big Sur 11.3 or later. 3. For watchOS, open Watch app on iPhone > General > Software Update. 4. Install watchOS 7.4 or later. 5. Restart devices after installation.
🔧 Temporary Workarounds
Disable automatic image processing
allPrevent automatic image rendering in email clients and web browsers
User education
allTrain users to avoid opening image files from untrusted sources
🧯 If You Can't Patch
- Implement application allowlisting to prevent unauthorized image processing applications
- Deploy network segmentation to isolate vulnerable systems and monitor for suspicious image processing activity
🔍 How to Verify
Check if Vulnerable:
Check macOS version: sw_vers -productVersion. If version is less than 11.3, system is vulnerable. For watchOS, check in Watch app on paired iPhone.Check Version:
macOS: sw_vers -productVersionVerify Fix Applied:
Confirm macOS version is 11.3 or higher: sw_vers -productVersion. Confirm watchOS version is 7.4 or higher in Watch app.📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes in image processing services
- Unusual image file access patterns
- Suspicious child processes spawned from image viewers
Network Indicators:
- Downloads of unusual image file types from untrusted sources
- Outbound connections from image processing applications
SIEM Query:
Process creation where parent process contains 'Preview', 'Photos', or image-related binaries AND child process is suspicious (e.g., shell, downloader)