CVE-2021-30790
📋 TL;DR
This vulnerability in macOS allows arbitrary code execution when opening a maliciously crafted file. It affects macOS Big Sur, Catalina, and Mojave systems. Attackers could exploit this to take control of affected systems.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control, data theft, and persistence.
Likely Case
Local privilege escalation or application crashes leading to denial of service.
If Mitigated
No impact if systems are fully patched and file execution is restricted.
🎯 Exploit Status
Requires user interaction to open malicious file. No public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.5, Security Update 2021-004 Catalina, Security Update 2021-005 Mojave
Vendor Advisory: https://support.apple.com/en-us/HT212600
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install available updates. 3. Restart when prompted.
🔧 Temporary Workarounds
Restrict file execution
allUse application whitelisting to prevent execution of untrusted files.
User education
allTrain users to avoid opening files from untrusted sources.
🧯 If You Can't Patch
- Implement strict file execution policies and application whitelisting.
- Use endpoint detection and response (EDR) tools to monitor for suspicious file execution.
🔍 How to Verify
Check if Vulnerable:
Check macOS version in System Preferences > About This Mac.Check Version:
sw_versVerify Fix Applied:
Verify macOS version is Big Sur 11.5 or later, or that Security Updates 2021-004/005 are installed.📡 Detection & Monitoring
Log Indicators:
- Unexpected application crashes
- Suspicious file execution events
Network Indicators:
- Downloads of suspicious files from untrusted sources
SIEM Query:
Search for application crash logs or file execution from untrusted locations.