CVE-2021-37133
📋 TL;DR
CVE-2021-37133 is an unauthorized file access vulnerability affecting certain Huawei smartphones running HarmonyOS. This vulnerability allows attackers to access sensitive files without proper authorization, potentially compromising service confidentiality. The issue affects specific Huawei device models with vulnerable HarmonyOS versions.
💻 Affected Systems
- Huawei smartphones with HarmonyOS
📦 What is this software?
Emui by Huawei
Emui by Huawei
Emui by Huawei
Emui by Huawei
Emui by Huawei
Harmonyos by Huawei
Harmonyos by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Attackers could access sensitive user data including personal files, authentication tokens, or configuration files, leading to complete compromise of device confidentiality and potential follow-on attacks.
Likely Case
Local attackers or malicious apps could access restricted files they shouldn't have permission to view, potentially exposing personal information or system configuration details.
If Mitigated
With proper security controls and patching, the vulnerability is eliminated, preventing unauthorized file access entirely.
🎯 Exploit Status
Exploitation likely requires local access or malicious app installation. No public exploit code was found in available references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: HarmonyOS security updates from November 2021 onward
Vendor Advisory: https://consumer.huawei.com/en/support/bulletin/2021/11/
Restart Required: Yes
Instructions:
1. Check for system updates in device Settings > System & updates > Software update. 2. Install available security updates. 3. Restart device after update completes.
🔧 Temporary Workarounds
Restrict app permissions
allLimit app permissions to minimum required, especially file access permissions
Avoid untrusted apps
allOnly install apps from official Huawei AppGallery and avoid sideloading untrusted applications
🧯 If You Can't Patch
- Isolate affected devices from sensitive networks and data
- Implement mobile device management (MDM) controls to restrict app installations and monitor for suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check device HarmonyOS version in Settings > About phone > HarmonyOS version and compare against Huawei's November 2021 security bulletinsCheck Version:
Settings > About phone > HarmonyOS version (no CLI command available)Verify Fix Applied:
Verify HarmonyOS version is updated to a version after the November 2021 security patches mentioned in Huawei advisories📡 Detection & Monitoring
Log Indicators:
- Unusual file access patterns from apps
- Permission violation attempts in system logs
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
Not applicable for typical mobile device scenarios🔗 References
- https://consumer.huawei.com/en/support/bulletin/2021/11/
- https://device.harmonyos.com/en/docs/security/update/security-bulletins-202111-0000001217889667
- https://consumer.huawei.com/en/support/bulletin/2021/11/
- https://device.harmonyos.com/en/docs/security/update/security-bulletins-202111-0000001217889667
