CVE-2021-22425
📋 TL;DR
This CVE describes a double free vulnerability in HarmonyOS that allows local attackers to gain root privileges. The vulnerability affects Huawei devices running vulnerable versions of HarmonyOS. Attackers need local access to exploit this memory corruption issue.
💻 Affected Systems
- Huawei HarmonyOS
📦 What is this software?
Harmonyos by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Local attacker gains full root/system privileges, enabling complete device compromise, data theft, persistence, and further lateral movement.
Likely Case
Local user or malware with limited privileges escalates to root to install persistent backdoors, bypass security controls, or access protected data.
If Mitigated
With proper patch management and least privilege principles, impact is limited to denial of service or application crashes.
🎯 Exploit Status
Requires local access and knowledge of memory layout. Double free vulnerabilities typically require specific conditions to achieve reliable exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: June 2021 security update
Vendor Advisory: https://device.harmonyos.com/cn/docs/security/update/oem_security_update_phone_202106-0000001165452077
Restart Required: Yes
Instructions:
1. Check for available updates in device Settings > System & updates > Software update. 2. Download and install June 2021 security update. 3. Reboot device after installation completes.
🔧 Temporary Workarounds
Restrict local access
allLimit physical and logical access to devices to trusted users only
Disable unnecessary local services
allReduce attack surface by disabling unused local interfaces and services
🧯 If You Can't Patch
- Isolate affected devices on network segments with strict access controls
- Implement application whitelisting to prevent execution of unauthorized binaries
🔍 How to Verify
Check if Vulnerable:
Check HarmonyOS version in Settings > About phone > HarmonyOS version. If version predates June 2021 security update, device is likely vulnerable.Check Version:
Settings > About phone > HarmonyOS version (GUI only, no CLI command provided)Verify Fix Applied:
Verify HarmonyOS version shows June 2021 security update installed. Check for absence of unexpected privilege escalation in system logs.📡 Detection & Monitoring
Log Indicators:
- Unexpected privilege escalation events
- Processes running with unexpected root privileges
- Memory allocation/deallocation errors in system logs
Network Indicators:
- Unusual outbound connections from system-level processes
SIEM Query:
Process creation events where parent process is non-privileged user but child process runs as root/UID 0