CVE-2021-22379
📋 TL;DR
This CVE describes an integer underflow vulnerability in Huawei smartphones' Samgr component, which could allow an attacker to cause a denial-of-service (DoS) by crashing the service. It affects Huawei smartphone users running vulnerable software versions. Exploitation requires local access to the device.
💻 Affected Systems
- Huawei smartphones
📦 What is this software?
Emui by Huawei
Magic Ui by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Complete DoS of the Samgr service, potentially disrupting system functionality and requiring a device restart.
Likely Case
Local DoS attack leading to temporary unavailability of affected services on the smartphone.
If Mitigated
Minimal impact if patched or with restricted local access; services remain operational.
🎯 Exploit Status
Exploitation likely requires local access and knowledge of the vulnerability; no public exploits known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Huawei security bulletins for specific patched versions (e.g., June 2021 updates).
Vendor Advisory: https://consumer.huawei.com/en/support/bulletin/2021/6/
Restart Required: Yes
Instructions:
1. Check for software updates in device settings. 2. Install the latest security patch from Huawei. 3. Restart the device after update.
🔧 Temporary Workarounds
Restrict local app permissions
allLimit app installations and permissions to reduce attack surface from malicious local apps.
🧯 If You Can't Patch
- Monitor device for unusual crashes or performance issues in Samgr-related services.
- Isolate vulnerable devices from untrusted networks and users to minimize local attack risk.
🔍 How to Verify
Check if Vulnerable:
Check device software version in settings and compare with Huawei's patched versions in advisories.Check Version:
On Huawei device: Settings > System & updates > Software update to view current version.Verify Fix Applied:
Confirm the installed software version matches or exceeds the patched version listed by Huawei.📡 Detection & Monitoring
Log Indicators:
- Logs showing Samgr service crashes or abnormal terminations on Huawei devices.
Network Indicators:
- No specific network indicators as it's a local vulnerability.
SIEM Query:
Example: 'event: Samgr crash OR service failure on Huawei device' in relevant logs.