CVE-2021-30784
📋 TL;DR
This vulnerability allows a local attacker to execute arbitrary code on the Apple T2 Security Chip in affected macOS systems. The attacker needs physical or local access to the device. This affects macOS Big Sur systems with T2 chips before version 11.5.
💻 Affected Systems
- macOS Big Sur with Apple T2 Security Chip
📦 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 compromise of the T2 Security Chip allowing persistent malware installation, firmware manipulation, and bypass of security features like FileVault encryption and Secure Boot.
Likely Case
Local privilege escalation allowing attackers to gain elevated privileges, access encrypted data, or install persistent backdoors.
If Mitigated
Limited impact if proper access controls prevent unauthorized local access and systems are kept in secure physical environments.
🎯 Exploit Status
Requires local access and sophisticated knowledge of T2 chip architecture. No public exploits have been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 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 macOS Big Sur 11.5 update. 3. Restart computer when prompted.
🔧 Temporary Workarounds
Restrict physical access
allEnsure Macs with T2 chips are kept in secure locations with controlled physical access
Enable FileVault
macOSFull disk encryption provides additional protection for data at rest
sudo fdesetup enable
🧯 If You Can't Patch
- Isolate affected systems from sensitive networks and data
- Implement strict physical security controls and access monitoring
🔍 How to Verify
Check if Vulnerable:
Check if system has T2 chip: Apple menu > About This Mac > System Report > Controller. Then check macOS version: Apple menu > About This Mac.Check Version:
sw_versVerify Fix Applied:
Verify macOS version is 11.5 or later: Apple menu > About This Mac.📡 Detection & Monitoring
Log Indicators:
- Unexpected T2 chip firmware modifications
- Unauthorized physical access logs
- Security policy violations
Network Indicators:
- Unusual outbound connections from T2 chip management interfaces
SIEM Query:
source="macos" AND (event="firmware_modification" OR event="physical_access")