CVE-2021-1759
📋 TL;DR
This vulnerability allows attackers to execute arbitrary code by tricking users into processing maliciously crafted images. It affects macOS, iOS, iPadOS, and tvOS systems running outdated versions. Successful exploitation could give attackers full control of the affected device.
💻 Affected Systems
- macOS
- iOS
- iPadOS
- 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
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise leading to data theft, ransomware deployment, or persistent backdoor installation
Likely Case
Malware installation, credential theft, or unauthorized access to sensitive data
If Mitigated
No impact if systems are patched or image processing is restricted
🎯 Exploit Status
Exploitation requires user interaction to process malicious image, but no authentication is needed once triggered.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, iOS 14.4, iPadOS 14.4
Vendor Advisory: https://support.apple.com/en-us/HT212146
Restart Required: Yes
Instructions:
1. Go to System Preferences > Software Update. 2. Install available updates. 3. Restart device when prompted.
🔧 Temporary Workarounds
Restrict image processing
allBlock or sandbox image processing applications
User education
allTrain users not to open images from untrusted sources
🧯 If You Can't Patch
- Implement application allowlisting to restrict which applications can process images
- Deploy network filtering to block malicious image downloads
🔍 How to Verify
Check if Vulnerable:
Check system version against affected versions listCheck Version:
macOS: sw_vers -productVersion; iOS/iPadOS: Settings > General > About > Version; tvOS: Settings > General > About > VersionVerify Fix Applied:
Verify system version is equal to or newer than patched versions📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes in image processing applications
- Unusual memory access patterns
Network Indicators:
- Downloads of suspicious image files from untrusted sources
SIEM Query:
Process:ImageProcessingApp AND (EventID:1000 OR Memory:OutOfBounds)