CVE-2021-30758
📋 TL;DR
This vulnerability allows attackers to execute arbitrary code on affected Apple devices by tricking users into visiting malicious websites. It affects iOS, Safari, macOS, watchOS, and tvOS devices running outdated versions. The type confusion issue in web content processing can be exploited without user interaction beyond loading web content.
💻 Affected Systems
- iOS
- Safari
- macOS
- watchOS
- tvOS
📦 What is this software?
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 →Safari by Apple
Tvos by Apple
Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of device with full system access, data theft, and persistent malware installation.
Likely Case
Browser-based compromise leading to session hijacking, credential theft, and installation of surveillance tools.
If Mitigated
Limited impact with proper network segmentation, web filtering, and endpoint protection blocking malicious sites.
🎯 Exploit Status
Type confusion vulnerabilities in browser engines are frequently exploited in the wild. No public exploit code is known, but similar vulnerabilities have been actively exploited.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 14.7, Safari 14.1.2, macOS Big Sur 11.5, watchOS 7.6, tvOS 14.7
Vendor Advisory: https://support.apple.com/en-us/HT212601
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 JavaScript
allPrevents exploitation by disabling JavaScript execution in Safari
Safari > Preferences > Security > Uncheck 'Enable JavaScript'
Use Alternative Browser
allSwitch to browsers not based on WebKit until patched
🧯 If You Can't Patch
- Implement strict web content filtering to block malicious sites
- Use application allowlisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check current OS version in Settings > General > About > Software VersionCheck Version:
sw_vers (macOS) or Settings > General > About (iOS)Verify Fix Applied:
Verify version number matches or exceeds patched versions listed in fix_official.patch_version📡 Detection & Monitoring
Log Indicators:
- Unusual Safari/WebKit process crashes
- Suspicious JavaScript execution patterns
Network Indicators:
- Connections to known malicious domains from Safari
- Unusual outbound traffic patterns
SIEM Query:
source="*safari*" AND (event="crash" OR event="exception") | stats count by host🔗 References
- https://support.apple.com/en-us/HT212601
- https://support.apple.com/en-us/HT212602
- https://support.apple.com/en-us/HT212604
- https://support.apple.com/en-us/HT212605
- https://support.apple.com/en-us/HT212606
- https://support.apple.com/en-us/HT212601
- https://support.apple.com/en-us/HT212602
- https://support.apple.com/en-us/HT212604
- https://support.apple.com/en-us/HT212605
- https://support.apple.com/en-us/HT212606
