CVE-2021-30743
📋 TL;DR
This vulnerability allows attackers to execute arbitrary code by tricking users into processing a maliciously crafted image. It affects Apple iOS, iPadOS, watchOS, tvOS, and macOS systems. Successful exploitation could give attackers full control of affected devices.
💻 Affected Systems
- iOS
- iPadOS
- watchOS
- tvOS
- macOS
📦 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
Complete system compromise leading to data theft, ransomware deployment, or persistent backdoor installation
Likely Case
Malicious app or website triggers image processing leading to privilege escalation or data exfiltration
If Mitigated
Attack fails due to patched systems or security controls preventing malicious image processing
🎯 Exploit Status
Exploitation requires user interaction (opening malicious image) but no authentication. No public exploit code known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 14.5, iPadOS 14.5, watchOS 7.4, tvOS 14.5, macOS Big Sur 11.3, Security Update 2021-003 Catalina
Vendor Advisory: https://support.apple.com/en-us/HT212317
Restart Required: Yes
Instructions:
1. Open Settings app. 2. Go to General > Software Update. 3. Install available updates. 4. Restart device when prompted.
🔧 Temporary Workarounds
Disable automatic image processing
allPrevent automatic image loading in email clients and web browsers
Application sandboxing
macOSUse sandboxed applications for image processing to limit potential damage
🧯 If You Can't Patch
- Implement application allowlisting to prevent unknown applications from processing images
- Deploy network filtering to block known malicious image delivery domains
🔍 How to Verify
Check if Vulnerable:
Check system version against affected versions list. On iOS/iPadOS: Settings > General > About > Version. On macOS: Apple menu > About This Mac.Check Version:
On macOS: sw_vers -productVersion. On iOS/iPadOS: UIDevice.current.systemVersion (programmatic)Verify Fix Applied:
Confirm system version is equal to or newer than patched versions listed in fix_official section📡 Detection & Monitoring
Log Indicators:
- Unexpected crashes in image processing applications
- Unusual process spawning from image viewers
Network Indicators:
- Downloads of suspicious image files from unknown sources
- Outbound connections after image processing
SIEM Query:
Process creation where parent process is image viewer/editor AND child process is cmd.exe/powershell/bash🔗 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/HT212530
- 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/HT212530
