CVE-2020-9901
📋 TL;DR
CVE-2020-9901 is a privilege escalation vulnerability in Apple's path validation logic for symbolic links. A local attacker could exploit improper symlink sanitization to gain elevated privileges on affected Apple devices. This affects iOS, iPadOS, macOS, and tvOS systems before specific security updates.
💻 Affected Systems
- iOS
- iPadOS
- macOS
- tvOS
📦 What is this software?
Ipados by Apple
Tvos by Apple
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains root privileges, potentially compromising the entire system, accessing sensitive data, and installing persistent malware.
Likely Case
Local user or malware with limited privileges escalates to higher privileges, enabling further system compromise and data access.
If Mitigated
With proper patching, the vulnerability is eliminated; with strict access controls, exploitation risk is reduced but not eliminated.
🎯 Exploit Status
Exploitation requires local access and knowledge of symlink manipulation; no public exploit code is documented.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: iOS 13.6, iPadOS 13.6, macOS Catalina 10.15.6, tvOS 13.4.8
Vendor Advisory: https://support.apple.com/kb/HT211288
Restart Required: Yes
Instructions:
1. Open Settings app. 2. Go to General > Software Update. 3. Install the available update. 4. Restart the device when prompted.
🔧 Temporary Workarounds
Restrict local user access
allLimit local user accounts and implement strict access controls to reduce attack surface.
🧯 If You Can't Patch
- Implement strict user access controls and monitor for suspicious local activity.
- Isolate affected systems from critical networks and data.
🔍 How to Verify
Check if Vulnerable:
Check the operating system version against affected versions listed in the Apple security advisory.Check Version:
On macOS: sw_vers -productVersion; On iOS/iPadOS/tvOS: Settings > General > About > VersionVerify Fix Applied:
Verify the device is running iOS 13.6+, iPadOS 13.6+, macOS Catalina 10.15.6+, or tvOS 13.4.8+.📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation attempts in system logs
- Suspicious symlink creation or manipulation
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
Search for events indicating privilege escalation or symlink-related anomalies on Apple devices.