CVE-2021-22394
📋 TL;DR
This CVE describes a buffer overflow vulnerability in Huawei smartphones that affects Multi-Screen Collaboration functionality. Successful exploitation could allow attackers to cause denial of service (DoS) to applications. The vulnerability affects specific Huawei smartphone models running HarmonyOS.
💻 Affected Systems
- Huawei smartphones with Multi-Screen Collaboration feature
📦 What is this software?
Emui by Huawei
Emui by Huawei
Emui by Huawei
Harmonyos by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Complete DoS of affected applications, potentially disrupting device functionality and user productivity.
Likely Case
Application crashes and temporary service disruption during Multi-Screen Collaboration sessions.
If Mitigated
Minimal impact with proper patching and security controls in place.
🎯 Exploit Status
Exploitation requires triggering the buffer overflow through Multi-Screen Collaboration interactions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: August 2021 security update for HarmonyOS
Vendor Advisory: https://consumer.huawei.com/en/support/bulletin/2021/7/
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System & updates > Software update. 2. Install the August 2021 security update. 3. Restart the device after installation.
🔧 Temporary Workarounds
Disable Multi-Screen Collaboration
allTemporarily disable the vulnerable feature until patching is complete
🧯 If You Can't Patch
- Disable Multi-Screen Collaboration feature in device settings
- Implement network segmentation to isolate vulnerable devices
🔍 How to Verify
Check if Vulnerable:
Check HarmonyOS version in Settings > About phone > HarmonyOS version. If version is before August 2021 security update, device is vulnerable.Check Version:
Settings > About phone > HarmonyOS versionVerify Fix Applied:
Verify HarmonyOS version includes August 2021 security update in Settings > About phone > HarmonyOS version.📡 Detection & Monitoring
Log Indicators:
- Application crash logs related to Multi-Screen Collaboration
- System logs showing buffer overflow errors
Network Indicators:
- Unusual Multi-Screen Collaboration traffic patterns
- Network connections attempting to trigger the vulnerability
SIEM Query:
Search for application crash events with process names related to Multi-Screen Collaboration or Huawei system services🔗 References
- https://consumer.huawei.com/en/support/bulletin/2021/7/
- https://device.harmonyos.com/en/docs/security/update/security-bulletins-phones-202108-0000001181125881
- https://consumer.huawei.com/en/support/bulletin/2021/7/
- https://device.harmonyos.com/en/docs/security/update/security-bulletins-phones-202108-0000001181125881
