CVE-2021-30748
📋 TL;DR
CVE-2021-30748 is a memory corruption vulnerability in Apple's iOS and macOS kernels that allows an application to execute arbitrary code with kernel privileges. This affects iOS devices and Mac computers running vulnerable versions. Successful exploitation gives attackers complete control over the affected device.
💻 Affected Systems
- iPhone
- iPad
- iPod touch
- Mac
📦 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
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise with kernel-level persistence, data theft, and ability to bypass all security controls
Likely Case
Malicious app gains kernel privileges to install persistent malware, intercept sensitive data, or disable security features
If Mitigated
Limited impact due to app sandboxing and code signing requirements, though kernel access bypasses these protections
🎯 Exploit Status
Exploitation requires user to install and run a malicious application. No public exploit code available as of knowledge cutoff.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 14.7, macOS Big Sur 11.5
Vendor Advisory: https://support.apple.com/en-us/HT212601
Restart Required: Yes
Instructions:
1. Open Settings app (iOS) or System Preferences (macOS). 2. Navigate to General > Software Update. 3. Download and install iOS 14.7 or macOS Big Sur 11.5. 4. Restart device when prompted.
🔧 Temporary Workarounds
Restrict App Installation
allLimit app installation to App Store only to reduce attack surface
iOS: Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Installing Apps > Don't Allow
macOS: System Preferences > Security & Privacy > General > Allow apps downloaded from: App Store
🧯 If You Can't Patch
- Implement strict app allowlisting policies through MDM solutions
- Monitor for unusual kernel activity or privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check iOS version: Settings > General > About > Version. Check macOS version: Apple menu > About This Mac > macOS versionCheck Version:
iOS: n/a (GUI only), macOS: sw_vers -productVersionVerify Fix Applied:
Verify version is iOS 14.7 or later, or macOS Big Sur 11.5 or later📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Unexpected kernel extensions loading
- Processes running with elevated privileges unexpectedly
Network Indicators:
- Unusual outbound connections from system processes
- DNS requests to suspicious domains from kernel space
SIEM Query:
source="apple_system_logs" AND (event="kernel_panic" OR process="kernel_task" AND action="privilege_escalation")