CVE-2021-22336
📋 TL;DR
This CVE describes an Improper Control of Generation of Code vulnerability in Huawei smartphones that allows attackers to execute arbitrary code on rooted devices. Successful exploitation could lead to denial of security services, potentially compromising device integrity. The vulnerability affects specific Huawei smartphone models with certain software versions.
💻 Affected Systems
- Huawei smartphones
📦 What is this software?
Emui by Huawei
Emui by Huawei
Emui by Huawei
Emui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of rooted device security services, allowing attackers to disable security features, execute arbitrary code with elevated privileges, and potentially gain persistent access to the device.
Likely Case
Temporary disruption of security services on rooted devices, potentially allowing malware to bypass security checks or gain elevated privileges for limited operations.
If Mitigated
Minimal impact on non-rooted devices or properly patched systems, with security services remaining functional and protected from unauthorized code execution.
🎯 Exploit Status
Exploitation requires root access on the target device, which significantly reduces attack surface. No public exploit code was mentioned in the provided references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: April 2021 security patch or later
Vendor Advisory: https://consumer.huawei.com/en/support/bulletin/2021/4/
Restart Required: Yes
Instructions:
1. Check for system updates in device Settings > System & updates > Software update. 2. Download and install the April 2021 security patch or later. 3. Restart the device after installation completes.
🔧 Temporary Workarounds
Disable root access
androidRemove root privileges from the device to eliminate the vulnerability's attack vector
adb shell su -c 'unroot' or use manufacturer-specific unrooting tools
Restrict physical access
allImplement physical security controls to prevent unauthorized access to rooted devices
🧯 If You Can't Patch
- Isolate rooted devices from critical networks and systems
- Implement application whitelisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check if device is rooted using root checker apps, then verify software version is before April 2021 patch in Settings > About phone > Build numberCheck Version:
adb shell getprop ro.build.display.idVerify Fix Applied:
Verify software version shows April 2021 or later security patch level in Settings > About phone > Build number📡 Detection & Monitoring
Log Indicators:
- Unexpected security service failures
- Root privilege escalation attempts in system logs
- Unauthorized code execution attempts
Network Indicators:
- Unusual outbound connections from rooted devices
- Communication with known malicious domains/IPs
SIEM Query:
DeviceLogs WHERE (event_type = 'security_service_failure' OR event_type = 'root_privilege_escalation') AND device_model CONTAINS 'Huawei'