CVE-2021-22332
📋 TL;DR
A double free vulnerability in Huawei CloudEngine switches allows attackers to cause memory corruption by freeing the same pointer twice. This can lead to denial of service through module crashes, potentially disrupting network services. Affected organizations are those using vulnerable versions of CloudEngine 5800, 6800, 7800, and 12800 series switches.
💻 Affected Systems
- CloudEngine 5800
- CloudEngine 6800
- CloudEngine 7800
- CloudEngine 12800
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption through switch module crashes, potentially affecting entire network segments and causing extended downtime.
Likely Case
Service interruption through targeted module crashes, requiring device reboots and causing temporary network outages.
If Mitigated
Limited impact with proper network segmentation and monitoring, allowing quick detection and recovery from crashes.
🎯 Exploit Status
Exploitation requires sending malicious operations to the switch, likely requiring some level of network access or authentication. No public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Huawei advisory for specific fixed versions
Vendor Advisory: https://www.huawei.com/en/psirt/security-advisories/huawei-sa-20210407-01-doublefree-en
Restart Required: Yes
Instructions:
1. Check Huawei advisory for exact affected versions. 2. Download appropriate firmware update from Huawei support. 3. Backup configuration. 4. Apply firmware update following Huawei documentation. 5. Reboot switch. 6. Verify update and restore functionality.
🔧 Temporary Workarounds
Network Segmentation
allIsolate switch management interfaces from untrusted networks and limit access to authorized administrators only.
Access Control Lists
allImplement strict ACLs to limit which IP addresses can communicate with switch management interfaces.
# Example ACL to restrict management access
acl number 3000
rule 5 permit ip source 10.0.0.0 0.255.255.255
rule 10 deny ip
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable switches from potential attackers
- Enable enhanced logging and monitoring for abnormal switch behavior or crash events
🔍 How to Verify
Check if Vulnerable:
Check switch firmware version against Huawei advisory: display versionCheck Version:
display versionVerify Fix Applied:
Verify firmware version is updated to patched version: display version📡 Detection & Monitoring
Log Indicators:
- Module crash logs
- Unexpected process termination
- Memory allocation errors
- System reboot events
Network Indicators:
- Unusual traffic patterns to switch management interfaces
- Service disruption alerts
SIEM Query:
source="switch_logs" AND ("crash" OR "panic" OR "memory error" OR "double free")