CVE-2020-37015: Ruijie Switch Path Traversal Vulnerability

CVE-2020-37015 Overview

Ruijie Networks Switch eWeb S29_RGOS 11.4 contains a directory traversal vulnerability that allows unauthenticated attackers to access sensitive configuration files by manipulating file path parameters. Attackers can exploit the /download.do endpoint with ../ sequences to retrieve system configuration files containing credentials and network settings.

Critical Impact

Unauthenticated attackers can read sensitive system configuration files including credentials and network settings, potentially leading to complete network device compromise.

Affected Products

• Ruijie Networks Switch eWeb S29_RGOS 11.4

Discovery Timeline

• 2026-01-29 - CVE CVE-2020-37015 published to NVD
• 2026-01-29 - Last updated in NVD database

Technical Details for CVE-2020-37015

Vulnerability Analysis

This directory traversal vulnerability (CWE-22) exists in the Ruijie Networks Switch eWeb management interface. The vulnerability allows remote attackers to escape the intended file system restrictions by injecting path traversal sequences into file download requests. When exploited, attackers can access arbitrary files on the underlying operating system, including configuration files that may contain plaintext or weakly-protected credentials, network topology information, and other sensitive data critical to network infrastructure security.

The attack requires network access to the eWeb management interface but does not require authentication, making it particularly dangerous for internet-exposed devices or those accessible from untrusted network segments.

Root Cause

The root cause is improper input validation in the file download functionality. The /download.do endpoint fails to properly sanitize user-supplied file path parameters, allowing directory traversal sequences (../) to be processed. This lack of input validation enables attackers to navigate outside the intended directory structure and access files anywhere on the file system that the web server process has permission to read.

Attack Vector

The attack is network-based and can be executed remotely without authentication. An attacker sends a crafted HTTP request to the /download.do endpoint with path traversal sequences in the file parameter. By using multiple ../ sequences, the attacker can traverse up the directory tree and then specify paths to sensitive system files such as configuration files, password files, or other critical system data.

The vulnerability mechanism works by exploiting the file download functionality. When a request is made to the /download.do endpoint, the application accepts a file path parameter that specifies which file to retrieve. Due to insufficient input sanitization, path traversal sequences like ../ are not filtered, allowing attackers to escape the web root directory. For example, a malicious request might include sequences such as ../../../etc/config to access system configuration files. Technical details and proof-of-concept information can be found in the Exploit-DB entry #48755 and the Faruk Tuygun Guide.

Detection Methods for CVE-2020-37015

Indicators of Compromise

• HTTP requests to /download.do containing ../ or encoded variants (%2e%2e%2f, %2e%2e/, ..%2f)
• Unusual file access patterns in web server logs targeting system configuration paths
• Authentication failures or credential changes following suspicious web interface access
• Unexpected network configuration modifications or new administrative accounts

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block path traversal sequences in HTTP requests
• Configure intrusion detection/prevention systems (IDS/IPS) with signatures for directory traversal patterns targeting Ruijie devices
• Implement log monitoring for requests to /download.do with anomalous file path parameters
• Enable file integrity monitoring on critical configuration files

Monitoring Recommendations

• Monitor web server access logs for repeated attempts to access sensitive file paths
• Alert on any successful file downloads from outside the intended web root directory
• Track authentication events and configuration changes following web interface access
• Review network traffic for exfiltration of configuration data from switch management interfaces

How to Mitigate CVE-2020-37015

Immediate Actions Required

• Restrict network access to the eWeb management interface to trusted IP addresses only
• Place management interfaces behind a VPN or jump host
• Implement network segmentation to isolate switch management traffic
• Review access logs for signs of prior exploitation

Patch Information

Contact Ruijie Networks for firmware updates addressing this vulnerability. Review the VulnCheck Advisory on Ruijie for additional remediation guidance and patch availability information.

Workarounds

• Disable the eWeb management interface if not required for operations
• Implement strict firewall rules limiting access to management ports from trusted networks only
• Deploy a reverse proxy with input validation to filter malicious requests before they reach the device
• Consider using out-of-band management networks for all network infrastructure devices

If direct patching is not immediately possible, apply network-level controls to restrict access to the management interface. The following example demonstrates firewall rule concepts for limiting management access:

# Example: Restrict management interface access to trusted subnet
# Adjust commands according to your firewall platform
# Allow management access only from trusted admin network (e.g., 10.0.0.0/24)
# Block all other access to the eWeb management port (typically 443 or 80)