CVE-2020-27897
📋 TL;DR
CVE-2020-27897 is an out-of-bounds write vulnerability in macOS that allows an application to execute arbitrary code with kernel privileges. This affects macOS systems running vulnerable versions, potentially giving attackers complete system control.
💻 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
Full system compromise with kernel-level privileges, allowing attackers to install persistent malware, steal sensitive data, or disable security controls.
Likely Case
Local privilege escalation where a malicious application gains kernel privileges to bypass security restrictions and access protected resources.
If Mitigated
Limited impact if systems are patched, applications are from trusted sources, and proper security controls like application sandboxing are enforced.
🎯 Exploit Status
Exploitation requires local access or ability to run malicious code on the target system. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: macOS Big Sur 11.1, Security Update 2020-001 Catalina, Security Update 2020-007 Mojave
Vendor Advisory: https://support.apple.com/en-us/HT211931
Restart Required: Yes
Instructions:
1. Open System Preferences > Software Update. 2. Install available security updates. 3. Restart the system when prompted.
🔧 Temporary Workarounds
Restrict application execution
allLimit execution of untrusted applications through Gatekeeper and application whitelisting
sudo spctl --master-enable
sudo spctl --enable
🧯 If You Can't Patch
- Implement strict application control policies to prevent execution of untrusted software
- Isolate vulnerable systems from critical network segments and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check macOS version in System Preferences > About This Mac. If version is older than Big Sur 11.1, Catalina Security Update 2020-001, or Mojave Security Update 2020-007, system is vulnerable.Check Version:
sw_versVerify Fix Applied:
Verify macOS version shows patched version and check that no security updates are pending in Software Update.📡 Detection & Monitoring
Log Indicators:
- Unusual kernel extensions loading
- Suspicious process spawning with elevated privileges
- Failed authorization attempts in system logs
Network Indicators:
- Unexpected outbound connections from system processes
- Network traffic to known malicious domains
SIEM Query:
source="macos_system_logs" AND (event="kernel_extension_load" OR event="privilege_escalation")