CVE-2020-3842
📋 TL;DR
This is a memory corruption vulnerability (CWE-787) in Apple operating systems that allows an application to execute arbitrary code with kernel privileges. It affects iOS, iPadOS, macOS, tvOS, and watchOS. Successful exploitation gives attackers complete control over affected devices.
💻 Affected Systems
- iOS
- iPadOS
- macOS
- tvOS
- watchOS
📦 What is this software?
Ipados by Apple
Tvos by Apple
Watchos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise: attacker gains kernel-level privileges, can install persistent malware, access all data, and control device functions.
Likely Case
Targeted attacks against specific users or organizations to steal sensitive data, install spyware, or establish persistence.
If Mitigated
Limited impact if devices are fully patched and have security controls like app sandboxing and code signing enforcement.
🎯 Exploit Status
Exploitation requires an attacker to get a malicious application installed on the target device, which typically requires user interaction or social engineering.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 13.3.1, iPadOS 13.3.1, macOS Catalina 10.15.3, tvOS 13.3.1, watchOS 6.1.2
Vendor Advisory: https://support.apple.com/HT210918
Restart Required: Yes
Instructions:
1. Go to Settings > General > Software Update on iOS/iPadOS/watchOS. 2. On macOS, go to System Preferences > Software Update. 3. On tvOS, go to Settings > System > Software Updates. 4. Download and install the latest update. 5. Restart device after installation.
🔧 Temporary Workarounds
Restrict App Installation
allOnly allow installation of apps from trusted sources like the App Store
On iOS/iPadOS: Settings > General > Device Management > Verify trusted sources
On macOS: System Preferences > Security & Privacy > Allow apps downloaded from: App Store
🧯 If You Can't Patch
- Isolate affected devices from critical networks and sensitive data
- Implement application allowlisting to prevent unauthorized app execution
🔍 How to Verify
Check if Vulnerable:
Check current OS version against affected versions listCheck Version:
iOS/iPadOS: Settings > General > About > Version; macOS: Apple menu > About This Mac; tvOS: Settings > General > About; watchOS: Watch app on iPhone > General > AboutVerify Fix Applied:
Verify OS version matches or exceeds patched versions listed in fix_official.patch_version📡 Detection & Monitoring
Log Indicators:
- Unexpected kernel extensions loading
- Unusual process spawning with elevated privileges
- System integrity protection (SIP) violations on macOS
Network Indicators:
- Unusual outbound connections from system processes
- Command and control traffic from kernel-level processes
SIEM Query:
process.parent.name:kernel AND process.name:sh OR process.name:bash OR process.name:cmd.exe