CVE-2021-31004
📋 TL;DR
This CVE describes a race condition vulnerability in macOS that could allow an application to gain elevated privileges. It affects macOS Big Sur and earlier versions of Monterey. The vulnerability was addressed through improved locking mechanisms in Apple's security updates.
💻 Affected Systems
- macOS
📦 What is this software?
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 →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
An attacker could execute arbitrary code with root privileges, potentially gaining complete control over the affected macOS system.
Likely Case
A malicious application could elevate its privileges to perform unauthorized actions, access sensitive data, or modify system files.
If Mitigated
With proper patching, the vulnerability is eliminated. Without patching, application sandboxing and least privilege principles can limit potential damage.
🎯 Exploit Status
Exploitation requires a malicious application to be executed on the target system. The race condition nature makes timing-dependent exploitation challenging but feasible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Monterey 12.0.1, macOS Big Sur 11.5
Vendor Advisory: https://support.apple.com/en-us/HT212602
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install available updates for macOS. 3. Restart the system when prompted.
🔧 Temporary Workarounds
Application Restriction
macosRestrict installation and execution of untrusted applications through macOS security settings
System Preferences > Security & Privacy > General > Allow apps downloaded from: App Store and identified developers
🧯 If You Can't Patch
- Implement strict application control policies to prevent execution of untrusted software
- Use macOS Gatekeeper to only allow signed applications from trusted developers
🔍 How to Verify
Check if Vulnerable:
Check macOS version: System Preferences > About This MacCheck Version:
sw_versVerify Fix Applied:
Verify macOS version is 12.0.1 or later for Monterey, or 11.5 or later for Big Sur📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation events in system logs
- Unexpected process creation with elevated privileges
Network Indicators:
- No direct network indicators - local exploitation only
SIEM Query:
source="macos_system_logs" AND (event="privilege_escalation" OR process_elevation=true)