CVE-2025-27718
📋 TL;DR
A path traversal vulnerability in the USB storage file-sharing function of HGW-BL1500HM devices allows attackers to access, modify, or delete files and potentially execute arbitrary code. This affects users of HGW-BL1500HM home gateway routers with vulnerable firmware versions. Attackers must be connected to the LAN side to exploit this vulnerability.
💻 Affected Systems
- HGW-BL1500HM
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through arbitrary code execution, leading to data theft, device takeover, and lateral movement within the network.
Likely Case
Unauthorized file access and modification of USB storage contents, potentially leading to data exfiltration or malware deployment.
If Mitigated
Limited impact if network segmentation prevents LAN access from untrusted devices and USB storage is not used.
🎯 Exploit Status
Exploitation requires crafting specific HTTP requests to vulnerable functions. No authentication bypass mentioned, but may be combined with other vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Ver 002.002.004 or later
Vendor Advisory: https://kddi-tech.com/contents/appendix_L2_06.html#64433e4a-8946-9c06-bddf-91cbfe56c8e5
Restart Required: No
Instructions:
1. Access router admin interface. 2. Navigate to firmware update section. 3. Download and install firmware version 002.002.004 or later from vendor. 4. Verify successful update.
🔧 Temporary Workarounds
Disable USB file-sharing
allTemporarily disable the vulnerable USB storage file-sharing function to prevent exploitation.
Network segmentation
allIsolate the router from untrusted devices using VLANs or firewall rules to restrict LAN-side access.
🧯 If You Can't Patch
- Disable USB storage file-sharing function completely
- Implement strict network access controls to limit which devices can communicate with the router
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface. If version is 002.002.003 or earlier, device is vulnerable.Check Version:
Login to router admin web interface and navigate to system information/firmware version pageVerify Fix Applied:
Confirm firmware version shows 002.002.004 or later in admin interface after update.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to USB file-sharing endpoints
- Multiple failed file access attempts from single source
Network Indicators:
- HTTP requests with path traversal patterns (../ sequences) to router IP
- Unusual file access patterns from LAN devices
SIEM Query:
source_ip=LAN_DEVICE AND dest_ip=ROUTER_IP AND (uri CONTAINS ".." OR uri CONTAINS "%2e%2e")