CVE-2021-39993
📋 TL;DR
This integer overflow vulnerability in Huawei smartphone ACPU components allows attackers to trigger out-of-bounds memory access. Successful exploitation could lead to arbitrary code execution or system crashes. Affects Huawei smartphone users with vulnerable devices.
💻 Affected Systems
- Huawei smartphones
📦 What is this software?
Emui by Huawei
Magic Ui by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing remote code execution with kernel privileges, enabling data theft, surveillance, or device bricking.
Likely Case
Application crashes, denial of service, or limited privilege escalation within the affected application context.
If Mitigated
No impact if patched or if exploit attempts are blocked by security controls.
🎯 Exploit Status
Integer overflow vulnerabilities typically require specific input conditions; exploitation may be challenging without detailed knowledge of memory layout.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Huawei security update for specific device model and firmware version
Vendor Advisory: https://consumer.huawei.com/en/support/bulletin/2021/12/
Restart Required: Yes
Instructions:
1. Check for security updates in device Settings > System & updates > Software update. 2. Download and install available updates. 3. Reboot device after installation completes.
🔧 Temporary Workarounds
Limit app installations
allRestrict installation of untrusted applications to reduce attack surface.
Settings > Security > Install unknown apps > Disable for all apps
🧯 If You Can't Patch
- Disable unnecessary device features and network connectivity when not in use
- Use mobile device management (MDM) solutions to enforce security policies and monitor for anomalies
🔍 How to Verify
Check if Vulnerable:
Check device firmware version in Settings > About phone > Build number and compare with Huawei security bulletinCheck Version:
Settings > About phone > Build numberVerify Fix Applied:
Verify security patch level in Settings > About phone > Build number includes December 2021 or later security updates📡 Detection & Monitoring
Log Indicators:
- Unexpected process crashes
- Kernel panic logs
- Memory access violation errors in system logs
Network Indicators:
- Unusual network traffic from device to suspicious endpoints
SIEM Query:
Device logs showing process crashes with memory violation errors (event_id related to access violations)