CVE-2021-30762
📋 TL;DR
CVE-2021-30762 is a use-after-free vulnerability in iOS that allows arbitrary code execution when processing malicious web content. Attackers can exploit this to take control of affected devices. This primarily affects iOS users who haven't updated to patched versions.
💻 Affected Systems
- iOS
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to data theft, surveillance, ransomware deployment, and lateral movement within networks.
Likely Case
Malicious code execution leading to credential theft, data exfiltration, and installation of persistent malware.
If Mitigated
Limited impact with proper network segmentation, application sandboxing, and security controls preventing successful exploitation.
🎯 Exploit Status
Apple confirmed active exploitation in the wild. Exploitation requires user interaction (visiting malicious website).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 12.5.4
Vendor Advisory: https://support.apple.com/en-us/HT212548
Restart Required: Yes
Instructions:
1. Go to Settings > General > Software Update. 2. Download and install iOS 12.5.4. 3. Restart device after installation completes.
🔧 Temporary Workarounds
Disable JavaScript in Safari
iosTemporarily disable JavaScript to prevent exploitation via web content
Settings > Safari > Advanced > JavaScript > Toggle Off
Use alternative browser with JavaScript disabled
iosUse browsers that allow JavaScript disabling or have additional security features
🧯 If You Can't Patch
- Segment affected devices from critical network resources
- Implement web filtering to block known malicious sites and restrict browsing
🔍 How to Verify
Check if Vulnerable:
Check iOS version in Settings > General > About > Version. If version is earlier than 12.5.4, device is vulnerable.Check Version:
Settings > General > About > VersionVerify Fix Applied:
Verify iOS version is 12.5.4 or later in Settings > General > About > Version.📡 Detection & Monitoring
Log Indicators:
- Safari crash logs with memory access violations
- Unexpected process creation from Safari/WebKit
Network Indicators:
- Connections to suspicious domains from iOS devices
- Unusual outbound traffic patterns
SIEM Query:
source="ios_logs" AND (process="Safari" OR process="WebKit") AND (event="crash" OR event="memory_violation")