CVE-2021-1774
📋 TL;DR
CVE-2021-1774 is a memory corruption vulnerability in Apple's image processing that allows arbitrary code execution when processing malicious images. Attackers can exploit this by tricking users into opening crafted image files. This affects macOS, iOS, iPadOS, watchOS, and tvOS users running vulnerable versions.
💻 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 with attacker gaining root privileges and persistent access to the device.
Likely Case
Malware installation, data theft, or device takeover when users open malicious images from untrusted sources.
If Mitigated
No impact if patched; limited to sandboxed apps if unpatched but with proper app restrictions.
🎯 Exploit Status
Exploitation requires user interaction to process malicious images; no public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4, iPadOS 14.4
Vendor Advisory: https://support.apple.com/en-us/HT212146
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install available updates. 3. Restart device when prompted.
🔧 Temporary Workarounds
Disable automatic image processing
allPrevent automatic image rendering in email clients and web browsers.
🧯 If You Can't Patch
- Restrict image file processing from untrusted sources
- Use application sandboxing to limit potential damage
🔍 How to Verify
Check if Vulnerable:
Check system version against affected versions list.Check Version:
macOS: sw_vers -productVersion; iOS/iPadOS: Settings > General > About > VersionVerify Fix Applied:
Verify system version matches or exceeds patched versions.📡 Detection & Monitoring
Log Indicators:
- Crash reports from image processing services
- Unexpected process execution following image file access
Network Indicators:
- Downloads of suspicious image files from untrusted sources
SIEM Query:
Process creation events following image file access from untrusted locations🔗 References
- https://support.apple.com/en-us/HT212146
- https://support.apple.com/en-us/HT212147
- https://support.apple.com/en-us/HT212148
- https://support.apple.com/en-us/HT212149
- https://support.apple.com/en-us/HT212146
- https://support.apple.com/en-us/HT212147
- https://support.apple.com/en-us/HT212148
- https://support.apple.com/en-us/HT212149
