CVE-2021-40004
📋 TL;DR
This CVE describes a permission management vulnerability in cellular modules that could allow unauthorized access to sensitive data. It affects devices running HarmonyOS with vulnerable cellular modules. Attackers could potentially bypass intended permission controls to access protected data.
💻 Affected Systems
- HarmonyOS devices with cellular modules
📦 What is this software?
Harmonyos by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of cellular module data including sensitive communications, location data, and device identifiers leading to privacy violations and potential credential theft.
Likely Case
Unauthorized access to some protected data stored or processed by the cellular module, potentially exposing user information or device telemetry.
If Mitigated
Limited or no data exposure due to proper access controls, network segmentation, and monitoring in place.
🎯 Exploit Status
Exploitation requires access to the cellular module interface and knowledge of the permission bypass mechanism.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to HarmonyOS security bulletins for specific patched versions
Vendor Advisory: https://device.harmonyos.com/en/docs/security/update/security-bulletins-202112-0000001183296718
Restart Required: Yes
Instructions:
1. Check current HarmonyOS version. 2. Apply security updates through official update channels. 3. Reboot device after update completes. 4. Verify update was successful.
🔧 Temporary Workarounds
Disable cellular data when not needed
allReduce attack surface by disabling cellular connectivity when Wi-Fi is available
Implement network segmentation
allIsolate cellular modules from sensitive network segments
🧯 If You Can't Patch
- Implement strict access controls to cellular module interfaces
- Monitor cellular module access logs for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check HarmonyOS version against affected versions in security bulletinCheck Version:
Settings > About phone > HarmonyOS versionVerify Fix Applied:
Verify HarmonyOS version matches or exceeds patched version in security bulletin📡 Detection & Monitoring
Log Indicators:
- Unauthorized access attempts to cellular module APIs
- Permission denial logs for cellular module functions
Network Indicators:
- Unexpected cellular module data transmissions
- Anomalous cellular data usage patterns
SIEM Query:
source="cellular_module" AND (event_type="permission_denied" OR event_type="unauthorized_access")