CVE-2019-15065
📋 TL;DR
This vulnerability in HiNet GPON firmware allows unauthenticated remote attackers to read arbitrary files on affected devices by sending a specific command to port 6998. It affects HiNet GPON routers with firmware versions before I040GWR190731. The high CVSS score reflects the ability to access sensitive system files without authentication.
💻 Affected Systems
- HiNet GPON routers
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could read sensitive configuration files, credentials, or system files, potentially leading to complete device compromise and lateral movement into internal networks.
Likely Case
Remote attackers reading router configuration files to obtain credentials, network information, or other sensitive data that could enable further attacks.
If Mitigated
If properly segmented and firewalled, impact limited to the device itself without network access to other systems.
🎯 Exploit Status
The vulnerability requires sending a specific command to port 6998; technical details are publicly available in CERT advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: I040GWR190731 or later
Vendor Advisory: https://www.twcert.org.tw/en/cp-128-3016-b0e90-2.html
Restart Required: Yes
Instructions:
1. Check current firmware version. 2. Download firmware version I040GWR190731 or later from vendor. 3. Upload and apply firmware update through device management interface. 4. Reboot device to complete installation.
🔧 Temporary Workarounds
Block port 6998 at firewall
linuxPrevent external access to the vulnerable service by blocking port 6998 at network perimeter.
iptables -A INPUT -p tcp --dport 6998 -j DROP
iptables -A INPUT -p udp --dport 6998 -j DROP
Disable unnecessary services
allIf possible, disable the service running on port 6998 if not required for device functionality.
🧯 If You Can't Patch
- Segment affected devices in isolated network zones to limit potential lateral movement
- Implement strict network access controls to allow only necessary traffic to/from affected devices
🔍 How to Verify
Check if Vulnerable:
Check if port 6998 is open and responding to connections: 'nc -zv [device_ip] 6998' or 'telnet [device_ip] 6998'Check Version:
Check device web interface or use vendor-specific CLI commands to display firmware versionVerify Fix Applied:
Verify firmware version is I040GWR190731 or later and port 6998 no longer responds to the specific exploit command.📡 Detection & Monitoring
Log Indicators:
- Unusual connections to port 6998
- Multiple failed or successful file access attempts via the service
Network Indicators:
- Traffic to port 6998 from unexpected sources
- Specific command patterns sent to port 6998
SIEM Query:
destination_port=6998 AND (protocol=tcp OR protocol=udp) AND NOT source_ip IN [allowed_ips]