CVE-2023-3675

Executive Summary

CVE-2023-3675 is a path traversal vulnerability in Secomea GateManager's Web GUI, affecting versions from 11.0.623074018 before 11.0.623373051. This flaw allows an authenticated attacker to read arbitrary files from the system resources, potentially exposing sensitive configuration data, credentials, or other critical information. The vulnerability has a CVSS score of 6.5 (Medium) and is classified under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory). No public proof-of-concept (PoC) or exploit code is currently available, and the EPSS score is 0.0%, indicating low exploitation activity in the wild. However, given the nature of the vulnerability and the criticality of GateManager in industrial environments, immediate patching is recommended.

CVSS Breakdown & Threat Level

• CVSS Score: 6.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: None
• Availability Impact: None

The threat level is elevated due to the potential for data exfiltration from industrial control systems (ICS) environments where GateManager is commonly deployed. The low attack complexity and network accessibility make it attractive for targeted attacks.

Deep Dive & Mechanics

The vulnerability resides in the Web GUI component of Secomea GateManager, which is used for remote management of industrial gateways. The path traversal occurs when the application fails to properly sanitize user-supplied input used to construct file paths. An attacker with low privileges can craft a request containing directory traversal sequences (e.g., ../) to read files outside the intended web root directory.

Root Cause: The application does not validate or restrict the path parameter in certain HTTP requests, allowing traversal to arbitrary system files.

Attack Scenario:

1. An attacker authenticates to the GateManager Web GUI with low-privileged credentials.
2. The attacker sends a specially crafted HTTP GET request to a vulnerable endpoint, such as /file?path=../../../etc/passwd.
3. The server reads the requested file and returns its contents in the HTTP response.
4. The attacker can then read sensitive files like configuration files, SSH keys, or database credentials.

Impact: Successful exploitation leads to unauthorized disclosure of sensitive data, which can be used for further lateral movement or privilege escalation within the ICS network.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

@app.route('/file')
def read_file():
    file_path = request.args.get('path')
    # No validation of file_path
    with open(file_path, 'r') as f:
        return f.read()

Patched Code (Conceptual):

import os

@app.route('/file')
def read_file():
    file_path = request.args.get('path')
    # Restrict to a specific directory
    base_dir = '/var/www/gatemanager/files'
    safe_path = os.path.normpath(os.path.join(base_dir, file_path))
    if not safe_path.startswith(base_dir):
        return "Access denied", 403
    with open(safe_path, 'r') as f:
        return f.read()

The patched version uses os.path.normpath and os.path.join to resolve the path and then checks that the resolved path starts with the allowed base directory, preventing traversal.

Exploitation & Lab Setup

Red Team

Lab Setup:

• Target: Secomea GateManager version 11.0.623074018 (vulnerable)
• Attacker: Kali Linux with Burp Suite or curl

Exploitation Steps:

1. Authenticate to the GateManager Web GUI (e.g., https://target-ip:8443).
2. Capture a valid session cookie.
3. Send a crafted request to read sensitive files:

   curl -k -X GET "https://target-ip:8443/file?path=../../../etc/passwd" -H "Cookie: session=valid_session_cookie"
   

4. If successful, the response will contain the contents of /etc/passwd.

Advanced Exploitation:

• Read configuration files to extract database credentials or SSH keys.
• Use the obtained credentials for lateral movement to other ICS devices.

Blue Team

Detection Steps:

• Monitor for HTTP requests containing ../ or ..%2f in the path parameter.
• Alert on attempts to read sensitive files like /etc/passwd, /etc/shadow, or application configuration files.
• Review authentication logs for unusual access patterns to the Web GUI.

Honeypot Strategy:

• Deploy a decoy GateManager instance with fake sensitive files to lure attackers.
• Log all file read attempts and correlate with other network events.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP GET requests with path parameters containing ../ sequences.
  • Requests to endpoints like /file, /download, or /read with traversal patterns.
  • Outbound data transfers from the GateManager server to external IPs.

• File IOCs:

  • Unauthorized access to /etc/passwd, /etc/shadow, or application configuration files.
  • Presence of unexpected files in the web root directory.

• System IOCs:

  • Unusual processes reading sensitive files.
  • Modified file access timestamps on critical system files.

Detection Engineering

YARA Rule

rule CVE_2023_3675_Path_Traversal {
    meta:
        description = "Detects path traversal attempts in HTTP requests targeting Secomea GateManager"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-3675"
    strings:
        $traversal1 = "../"
        $traversal2 = "..\\"
        $traversal3 = "%2e%2e%2f"
        $traversal4 = "%2e%2e%5c"
        $sensitive1 = "/etc/passwd"
        $sensitive2 = "/etc/shadow"
        $sensitive3 = "config.xml"
    condition:
        any of ($traversal*) and any of ($sensitive*)
}

Sigma Rule

title: CVE-2023-3675 Path Traversal Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects path traversal attempts in HTTP requests to Secomea GateManager
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains:
            - '../'
            - '..\\'
            - '%2e%2e%2f'
            - '%2e%2e%5c'
    condition: selection
falsepositives:
    - Legitimate use of relative paths in some applications
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-3675 Path Traversal Attempt"; flow:to_server,established; content:"GET"; http_method; content:"../"; http_uri; nocase; content:"/etc/passwd"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade to GateManager version 11.0.623373051 or later.
2. If patching is not possible, restrict access to the Web GUI to trusted IPs only.
3. Implement a Web Application Firewall (WAF) rule to block path traversal patterns.

Long-term Measures:

• Conduct regular security audits of the GateManager configuration.
• Implement the principle of least privilege for user accounts.
• Enable detailed logging and monitoring for all Web GUI access.
• Apply vendor security patches promptly.

Workarounds:

• Disable the vulnerable endpoint if not required.
• Use network segmentation to isolate the GateManager from untrusted networks.

Report generated by Valters IT DevSecOps & CTI Division