CVE-2021-30698
📋 TL;DR
This CVE describes a null pointer dereference vulnerability in Apple's macOS, iOS, iPadOS, and Safari that could allow a remote attacker to cause a denial of service. The vulnerability affects users running older versions of these Apple operating systems and browsers. Successful exploitation could crash affected applications or systems.
💻 Affected Systems
- macOS
- Safari
- iOS
- iPadOS
📦 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 →Safari by Apple
⚠️ Risk & Real-World Impact
Worst Case
Complete system crash or application termination leading to denial of service, potentially requiring system reboot.
Likely Case
Application crash (Safari browser crash) when processing malicious content, causing temporary disruption.
If Mitigated
No impact if systems are patched to the fixed versions.
🎯 Exploit Status
Remote exploitation possible without authentication. The vulnerability is in input validation, making exploitation relatively straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.4, Safari 14.1.1, iOS 14.6, iPadOS 14.6
Vendor Advisory: https://support.apple.com/en-us/HT212528
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update on macOS or Settings > General > Software Update on iOS/iPadOS. 2. Install available updates. 3. Restart device when prompted. For Safari only updates, use App Store updates on macOS.
🔧 Temporary Workarounds
Disable JavaScript
macOSTemporarily disable JavaScript in Safari to prevent exploitation through web content
Safari > Preferences > Security > uncheck 'Enable JavaScript'
🧯 If You Can't Patch
- Restrict access to untrusted websites and web content
- Use alternative browsers temporarily until patching is possible
🔍 How to Verify
Check if Vulnerable:
Check current OS/browser version against affected versions. On macOS: About This Mac > Overview. On iOS/iPadOS: Settings > General > About > Version. In Safari: Safari > About Safari.Check Version:
macOS: sw_vers -productVersion, iOS/iPadOS: Settings app, Safari: defaults read /Applications/Safari.app/Contents/Info.plist CFBundleShortVersionStringVerify Fix Applied:
Verify version is equal to or greater than: macOS 11.4, Safari 14.1.1, iOS 14.6, iPadOS 14.6📡 Detection & Monitoring
Log Indicators:
- Application crash logs for Safari or system processes
- Kernel panic logs indicating null pointer dereference
Network Indicators:
- Multiple rapid requests to malicious domains followed by application crashes
SIEM Query:
source="*crash*" AND (process="Safari" OR process="WebKit") AND message="*null*" OR "*dereference*"