CVE-2025-4186: Wangshen SecGate 3600 Path Traversal Flaw

CVE-2025-4186 Overview

CVE-2025-4186 is a path traversal vulnerability in Wangshen SecGate 3600 2024. The flaw resides in the /?g=route_ispinfo_export_save endpoint, where the file_name argument is not properly sanitized. Attackers can manipulate this parameter to traverse the file system and access files outside the intended directory. The vulnerability is exploitable remotely over the network and requires low privileges. Public disclosure of the exploit technique increases the likelihood of opportunistic scanning and abuse. The weakness is classified under CWE-22, Improper Limitation of a Pathname to a Restricted Directory.

Critical Impact
Remote authenticated attackers can read or write arbitrary files on the SecGate 3600 appliance, exposing configuration data and credentials.

Affected Products

Wangshen SecGate 3600 2024
Affected endpoint: /?g=route_ispinfo_export_save
Vulnerable parameter: file_name

Discovery Timeline

2025-05-02 - CVE-2025-4186 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-4186

Vulnerability Analysis

The vulnerability affects the ISP information export functionality of SecGate 3600. The handler processing /?g=route_ispinfo_export_save accepts a file_name parameter and uses it to construct a file path without adequate validation. Attackers who supply directory traversal sequences such as ../ can escape the intended export directory. This allows access to sensitive files stored elsewhere on the appliance. The endpoint is reachable over the network, which broadens the exposure surface for any internet-facing deployment.

Root Cause

The root cause is missing or insufficient input sanitization on the file_name parameter. The application concatenates user-controlled input directly into a file system path without canonicalization or allowlist checks. This matches the CWE-22 pattern of improper pathname restriction.

Attack Vector

An attacker sends a crafted HTTP request to the vulnerable endpoint with traversal sequences embedded in file_name. Because the flaw requires low privileges but no user interaction, any authenticated user or compromised low-privilege account can trigger it. Successful exploitation can lead to disclosure of configuration files, credentials, or session material stored on the appliance. Refer to the VulDB entry and the Flowus disclosure document for reproduction details.

Detection Methods for CVE-2025-4186

Indicators of Compromise

HTTP requests to /?g=route_ispinfo_export_save containing ../, ..\, URL-encoded %2e%2e%2f, or double-encoded traversal sequences in the file_name parameter.
Unusual outbound transfers of configuration files, credential stores, or system files originating from the SecGate 3600 management interface.
Access log entries showing repeated failed or successful export requests from unexpected source IP addresses.

Detection Strategies

Deploy web application firewall (WAF) rules that inspect query strings for traversal patterns targeting the affected endpoint.
Correlate authentication logs with export-endpoint activity to flag low-privilege accounts accessing sensitive functions.
Enable verbose HTTP request logging on the appliance and forward events to a centralized SIEM for pattern analysis.

Monitoring Recommendations

Alert on any HTTP request to route_ispinfo_export_save originating from outside authorized administrator subnets.
Monitor for spikes in 200-OK responses to export endpoints followed by large response bodies.
Track file access anomalies on the appliance, particularly reads of configuration, /etc/passwd, or credential files.

How to Mitigate CVE-2025-4186

Immediate Actions Required

Restrict network access to the SecGate 3600 management interface using firewall rules or VPN gating.
Revoke or rotate any credentials that may have been exposed through the vulnerable endpoint.
Audit account activity for unauthorized export operations since the appliance was deployed.
Contact Wangshen for an official security patch and apply it as soon as it becomes available.

Patch Information

At the time of publication, no vendor advisory or patch reference is listed in NVD for CVE-2025-4186. Operators should contact Wangshen directly and monitor the VulDB CTI entry for updates.

Workarounds

Block requests containing traversal sequences (.., %2e%2e, encoded variants) at an upstream reverse proxy or WAF.
Disable or restrict the ISP information export function if it is not required for operations.
Enforce network segmentation so the appliance management plane is unreachable from untrusted networks.
Require multi-factor authentication for all administrative accounts to reduce the risk of low-privilege account misuse.

bash

# Example WAF rule concept for blocking traversal on the affected endpoint
# (adapt syntax to your WAF vendor)
SecRule REQUEST_URI "@contains /?g=route_ispinfo_export_save" \
  "chain,deny,status:403,id:1004186,msg:'CVE-2025-4186 path traversal attempt'"
SecRule ARGS:file_name "@rx (\.\./|\.\.\\|%2e%2e%2f|%2e%2e/)" "t:none,t:lowercase"