CVE-2021-1867
📋 TL;DR
CVE-2021-1867 is an out-of-bounds read vulnerability in Apple's iOS, iPadOS, and macOS that allows malicious applications to execute arbitrary code with kernel privileges. This affects users running vulnerable versions of these operating systems, potentially giving attackers full system control.
💻 Affected Systems
- iOS
- iPadOS
- macOS
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with kernel-level privileges, allowing attackers to install persistent malware, steal sensitive data, or disable security controls.
Likely Case
Malicious applications gaining elevated privileges to bypass sandboxing and access protected system resources or user data.
If Mitigated
Limited impact if systems are fully patched and application installation is restricted to trusted sources only.
🎯 Exploit Status
Exploitation requires user interaction to install a malicious application. No public exploit code has been confirmed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 14.5, iPadOS 14.5, macOS Big Sur 11.3
Vendor Advisory: https://support.apple.com/en-us/HT212317
Restart Required: Yes
Instructions:
1. Open Settings app. 2. Go to General > Software Update. 3. Download and install iOS 14.5/iPadOS 14.5 or macOS Big Sur 11.3. 4. Restart device after installation completes.
🔧 Temporary Workarounds
Restrict Application Installation
allOnly allow installation of applications from trusted sources like the App Store
Settings > General > Device Management > Trust Enterprise Developer (for enterprise devices only)
🧯 If You Can't Patch
- Implement strict application control policies to prevent installation of untrusted applications
- Isolate vulnerable devices from critical network segments and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check current OS version in Settings > General > About > Version (iOS/iPadOS) or Apple menu > About This Mac (macOS)Check Version:
iOS/iPadOS: Settings > General > About > Version; macOS: sw_vers -productVersionVerify Fix Applied:
Verify version is iOS 14.5+, iPadOS 14.5+, or macOS Big Sur 11.3+📡 Detection & Monitoring
Log Indicators:
- Unusual kernel extensions loading
- Unexpected privilege escalation events
- Suspicious application installation logs
Network Indicators:
- Connections to known malicious domains from system processes
- Unusual outbound traffic from kernel-level processes
SIEM Query:
source="apple_system_logs" AND (event_type="kernel_extension_load" OR event_type="privilege_escalation")