CVE-2021-39976
📋 TL;DR
This is a privilege escalation vulnerability in Huawei CloudEngine 5800 switches where authenticated local attackers can perform specific operations to gain higher privileges. The vulnerability affects Huawei CloudEngine 5800 V200R020C00SPC600. Attackers need local access to the device to exploit this issue.
💻 Affected Systems
- Huawei CloudEngine 5800
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An authenticated attacker gains administrative/root privileges on the switch, allowing complete control over network configuration, traffic interception, and potential lateral movement to other systems.
Likely Case
An authenticated user with limited privileges escalates to administrative access, enabling unauthorized configuration changes, network disruption, or data exfiltration.
If Mitigated
With proper access controls and monitoring, exploitation would be detected and contained before significant damage occurs.
🎯 Exploit Status
Exploitation requires authenticated access and knowledge of specific operations. No public exploit code has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V200R020C00SPC600 and later versions
Vendor Advisory: https://www.huawei.com/en/psirt/security-advisories/huawei-sa-20211103-01-privilege-en
Restart Required: Yes
Instructions:
1. Download the latest firmware from Huawei support portal. 2. Backup current configuration. 3. Upload and install the updated firmware. 4. Reboot the switch. 5. Verify the new firmware version is running.
🔧 Temporary Workarounds
Restrict Management Access
allLimit access to switch management interfaces to only authorized administrators using strict network segmentation and access controls.
Implement Least Privilege
allReview and minimize user privileges on the switch to reduce the attack surface for privilege escalation.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate switch management interfaces from general user networks
- Enable comprehensive logging and monitoring of all administrative actions on the switch
🔍 How to Verify
Check if Vulnerable:
Check the firmware version using 'display version' command and verify if it matches V200R020C00SPC600Check Version:
display versionVerify Fix Applied:
After patching, run 'display version' command to confirm the firmware version has been updated beyond V200R020C00SPC600📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation attempts
- Unexpected administrative command execution by non-admin users
- Failed authentication attempts followed by successful privilege changes
Network Indicators:
- Unexpected configuration changes to switch interfaces or routing tables
- Unusual management traffic patterns to switch
SIEM Query:
source="cloudengine-switch" AND (event_type="privilege_escalation" OR user_change="admin" OR command="enable")