CVE-2021-37128
📋 TL;DR
CVE-2021-37128 is a path traversal vulnerability in HwPCAssistant that allows attackers to write arbitrary files to the filesystem. This affects Huawei devices running HarmonyOS with the vulnerable component. Successful exploitation could lead to system compromise.
💻 Affected Systems
- Huawei HarmonyOS devices with HwPCAssistant component
📦 What is this software?
Harmonyos by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover through arbitrary file write leading to remote code execution, data destruction, or persistent backdoor installation.
Likely Case
Local privilege escalation or unauthorized file modification affecting system integrity and confidentiality.
If Mitigated
Limited impact with proper file permissions and access controls preventing unauthorized writes to critical system locations.
🎯 Exploit Status
Exploitation requires local access to the device. The vulnerability is in file path validation allowing directory traversal sequences.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: HarmonyOS 2.0.0.210 and later
Vendor Advisory: https://device.harmonyos.com/en/docs/security/update/security-bulletins-202110-0000001162998526
Restart Required: Yes
Instructions:
1. Check current HarmonyOS version in Settings > About phone. 2. If version is earlier than 2.0.0.210, go to Settings > System & updates > Software update. 3. Download and install the latest update. 4. Restart device after installation completes.
🔧 Temporary Workarounds
Disable HwPCAssistant component
allTemporarily disable the vulnerable component if patching is not immediately possible
Restrict local user access
allImplement strict access controls to limit who can interact with the device locally
🧯 If You Can't Patch
- Implement strict file system permissions to limit write access to critical directories
- Monitor for suspicious file write activities and implement application whitelisting
🔍 How to Verify
Check if Vulnerable:
Check HarmonyOS version in Settings > About phone. If version is earlier than 2.0.0.210, the device is vulnerable.Check Version:
Settings > About phone > HarmonyOS versionVerify Fix Applied:
After updating, verify the HarmonyOS version is 2.0.0.210 or later in Settings > About phone.📡 Detection & Monitoring
Log Indicators:
- Unusual file write operations in system logs
- Access attempts to HwPCAssistant with path traversal patterns
Network Indicators:
- Local network connections to device management ports
SIEM Query:
source="harmonyos" AND (event="file_write" OR process="HwPCAssistant") AND path="*../*"