CVE-2021-1885
📋 TL;DR
This vulnerability allows attackers to execute arbitrary code by tricking users into processing a maliciously crafted image. It affects Apple devices running outdated versions of macOS, iOS, iPadOS, watchOS, and tvOS. Successful exploitation could give attackers full control of the affected device.
💻 Affected Systems
- macOS
- iOS
- iPadOS
- watchOS
- tvOS
📦 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
Full system compromise leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malware installation through phishing emails or malicious websites containing crafted images.
If Mitigated
Limited impact if devices are patched and users avoid suspicious image files.
🎯 Exploit Status
Exploitation requires user interaction with malicious image but no authentication. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.3, iOS 14.5, iPadOS 14.5, watchOS 7.4, tvOS 14.5
Vendor Advisory: https://support.apple.com/en-us/HT212317
Restart Required: Yes
Instructions:
1. Go to Settings > General > Software Update on iOS/iPadOS/watchOS/tvOS or System Preferences > Software Update on macOS. 2. Download and install the latest update. 3. Restart the device when prompted.
🔧 Temporary Workarounds
Disable automatic image processing
allConfigure email clients and browsers to not automatically load or process images from untrusted sources.
User education
allTrain users to avoid opening image files from unknown or suspicious sources.
🧯 If You Can't Patch
- Implement network filtering to block suspicious image files at perimeter.
- Deploy endpoint detection that monitors for abnormal image processing behavior.
🔍 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:
- Unusual process crashes related to image processing
- Suspicious file downloads of image formats
Network Indicators:
- Downloads of image files from suspicious domains
- Unusual outbound connections after image processing
SIEM Query:
Process execution where parent process is image viewer or browser AND command line contains image file extensions from untrusted sources🔗 References
- https://support.apple.com/en-us/HT212317
- https://support.apple.com/en-us/HT212323
- https://support.apple.com/en-us/HT212324
- https://support.apple.com/en-us/HT212325
- https://support.apple.com/en-us/HT212317
- https://support.apple.com/en-us/HT212323
- https://support.apple.com/en-us/HT212324
- https://support.apple.com/en-us/HT212325
