CVE-2021-1785
📋 TL;DR
CVE-2021-1785 is an out-of-bounds read vulnerability in Apple's image processing that could allow arbitrary code execution when processing malicious images. This affects macOS, iOS, iPadOS, watchOS, and tvOS users. Attackers could exploit this to gain control of affected devices.
💻 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
Application crash or limited code execution within the sandboxed image processing context.
If Mitigated
No impact if patched; limited impact if proper network filtering prevents malicious image delivery.
🎯 Exploit Status
Requires user to process a maliciously crafted image. 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
Image Source Restriction
allRestrict processing of images from untrusted sources
🧯 If You Can't Patch
- Implement network filtering to block malicious image files
- Use application whitelisting to restrict image processing applications
🔍 How to Verify
Check if Vulnerable:
Check system version against affected versions listCheck 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:
- Application crashes in image processing components
- Unexpected process execution following image handling
Network Indicators:
- Unusual image file downloads from untrusted sources
SIEM Query:
Process execution following image file access from suspicious sources🔗 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
