CVE-2021-30717
📋 TL;DR
This memory corruption vulnerability in macOS allows attackers in a privileged network position to execute arbitrary code on affected systems. It affects macOS Big Sur, Catalina, and Mojave before specific security updates. The vulnerability enables remote code execution without user interaction.
💻 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 over the affected macOS system, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Remote code execution allowing attackers to install malware, create backdoors, or exfiltrate sensitive data from vulnerable macOS systems.
If Mitigated
Limited impact if systems are patched, network segmentation is implemented, and privileged network positions are restricted.
🎯 Exploit Status
Exploitation requires attacker to be in a privileged network position (man-in-the-middle or network compromise). No authentication required for the exploit itself.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.4, Security Update 2021-003 Catalina, Security Update 2021-004 Mojave
Vendor Advisory: https://support.apple.com/en-us/HT212529
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install available security updates. 3. Restart the system when prompted. 4. Verify the update completed successfully.
🔧 Temporary Workarounds
Network Segmentation
allImplement strict network segmentation to limit privileged network positions and reduce attack surface
Network Monitoring
allDeploy network monitoring and intrusion detection systems to detect suspicious network activity
🧯 If You Can't Patch
- Implement strict network segmentation and access controls to limit privileged network positions
- Deploy network monitoring and intrusion detection systems to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check macOS version: 1. Click Apple menu > About This Mac. 2. If version is Big Sur < 11.4, Catalina without Security Update 2021-003, or Mojave without Security Update 2021-004, system is vulnerable.Check Version:
sw_versVerify Fix Applied:
Verify macOS version is Big Sur 11.4 or later, or that Catalina/Mojave have the specified security updates installed via About This Mac.📡 Detection & Monitoring
Log Indicators:
- Unexpected process execution
- Memory corruption errors in system logs
- Network traffic anomalies from macOS systems
Network Indicators:
- Unusual network traffic patterns to/from macOS systems
- Suspicious network positioning activity
SIEM Query:
source="macos_system_logs" AND (event="memory_corruption" OR process_execution="unexpected")