CVE-2019-5275
📋 TL;DR
This vulnerability affects Huawei USG9500 firewalls with specific firmware versions. A flaw in the X.509 certificate parsing implementation causes a heap buffer overflow when processing malicious certificates, allowing attackers to crash the device and cause denial of service. Organizations using affected USG9500 firewalls with vulnerable firmware are at risk.
💻 Affected Systems
- Huawei USG9500
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash requiring manual reboot, disrupting all network traffic passing through the firewall and potentially causing extended network downtime.
Likely Case
Service disruption on affected firewall, requiring reboot to restore functionality and causing temporary network connectivity issues.
If Mitigated
No impact if device is patched or not exposed to malicious certificates.
🎯 Exploit Status
Attack requires sending a specially crafted certificate to the device, which could be done through various network protocols that use certificate authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to V500R001C30SPC100 or later for C30 branch, or V500R001C60SPC100 or later for C60 branch
Vendor Advisory: https://www.huawei.com/en/psirt/security-advisories/huawei-sa-20191225-01-eudemon-en
Restart Required: Yes
Instructions:
1. Download firmware update from Huawei support portal. 2. Backup current configuration. 3. Upload and install firmware update via web interface or CLI. 4. Reboot device. 5. Verify firmware version after reboot.
🔧 Temporary Workarounds
Certificate filtering
allImplement network filtering to block or inspect certificates before they reach the firewall
Network segmentation
allRestrict access to certificate processing services on the firewall
🧯 If You Can't Patch
- Implement strict network access controls to limit who can send certificates to the firewall
- Monitor for abnormal certificate traffic and device crashes, with rapid response procedures
🔍 How to Verify
Check if Vulnerable:
Check firmware version via CLI: display version. If version is V500R001C30 or V500R001C60 without SPC100 patch, device is vulnerable.Check Version:
display versionVerify Fix Applied:
After update, verify version shows V500R001C30SPC100 or higher, or V500R001C60SPC100 or higher.📡 Detection & Monitoring
Log Indicators:
- Firewall crash logs
- Unexpected reboots
- Certificate parsing errors in system logs
Network Indicators:
- Unusual certificate traffic to firewall management interfaces
- Multiple certificate submission attempts
SIEM Query:
source="firewall" AND (event_type="crash" OR event_type="reboot" OR message="*certificate*error*")