CVE-2021-30664
📋 TL;DR
This CVE describes an out-of-bounds write vulnerability in Apple operating systems that could allow arbitrary code execution when processing malicious files. Attackers could exploit this to run unauthorized code on affected devices. The vulnerability impacts macOS, iOS, iPadOS, watchOS, and tvOS users running outdated versions.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 complete control over the device, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malicious file execution leading to limited code execution in the context of the vulnerable application, potentially enabling data exfiltration or further privilege escalation.
If Mitigated
No impact if systems are fully patched or if malicious files are blocked from reaching vulnerable systems.
🎯 Exploit Status
Exploitation requires user interaction to process a malicious file. No public proof-of-concept has been disclosed, but the vulnerability type (out-of-bounds write) is commonly exploited.
🛠️ 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. Open Settings/System Preferences. 2. Navigate to Software Update. 3. Download and install the latest update. 4. Restart the device when prompted.
🔧 Temporary Workarounds
File Type Restriction
allRestrict processing of untrusted files by implementing application whitelisting or file type restrictions.
User Education
allTrain users to avoid opening files from untrusted sources and to verify file integrity before processing.
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable systems from critical assets
- Deploy endpoint protection that can detect and block malicious file execution attempts
🔍 How to Verify
Check if Vulnerable:
Check the operating system version against the patched versions listed in the affected systems section.Check Version:
macOS: sw_vers -productVersion; iOS/iPadOS: Settings > General > About > Version; watchOS: Watch app > General > About > Version; tvOS: Settings > General > About > VersionVerify Fix Applied:
Verify the operating system version matches or exceeds the patched versions: macOS 11.3+, iOS 14.5+, iPadOS 14.5+, watchOS 7.4+, tvOS 14.5+.📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes related to file processing
- Unusual file execution events from untrusted sources
Network Indicators:
- Downloads of suspicious file types from untrusted sources
- Outbound connections following file processing
SIEM Query:
Process execution events where parent process is a file handler application and command line contains suspicious file paths or extensions🔗 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
