CVE-2025-65014

Executive Summary

CVE-2025-65014 identifies a weak password policy vulnerability in LibreNMS, an auto-discovering PHP/MySQL/SNMP based network monitoring tool. Prior to version 25.11.0, the user management functionality allowed administrators to create accounts with extremely weak and predictable passwords (e.g., "12345678"). This flaw exposes the platform to brute-force and credential stuffing attacks, potentially leading to unauthorized access. The vulnerability has been patched in version 25.11.0.

Supply Chain & Package Security

LibreNMS is a PHP/MySQL/SNMP based application, not an NPM, PyPI, Go, or Ruby package. Therefore, this section is not applicable.

CVSS Breakdown & Threat Level

• CVSS Score: 3.7 (Low)
• Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N
• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): High (H) – An attacker must first have administrative access to create weak accounts.
• User Interaction (UI): None (N) – No user action is required.
• Scope (S): Unchanged (U) – The impact is confined to the vulnerable component.
• Confidentiality (C): Low (L) – Limited information disclosure possible.
• Integrity (I): Low (L) – Limited data modification possible.
• Availability (A): None (N) – No impact on availability.

Threat Level: Low. The vulnerability requires high privileges to exploit initially, but once a weak account is created, it can be targeted by brute-force attacks.

Deep Dive & Mechanics

The vulnerability lies in the user management functionality of LibreNMS. The application does not enforce a strong password policy when administrators create new user accounts. This allows the creation of accounts with passwords that are easily guessable or susceptible to brute-force attacks.

Root Cause: Lack of password complexity validation in the user creation process. The application does not check for minimum length, character diversity, or common weak passwords.

Attack Scenario:

1. An attacker gains administrative access to the LibreNMS instance (e.g., through another vulnerability or stolen credentials).
2. The attacker creates a new user account with a weak password (e.g., "12345678").
3. The attacker then uses brute-force or credential stuffing techniques to compromise the weak account.
4. Once compromised, the attacker can access the LibreNMS interface with the privileges assigned to that account.

Vulnerable vs. Patched Code

Vulnerable Code (Pre-25.11.0): The user creation endpoint likely accepts any password without validation.

// Vulnerable: No password strength check
$password = $_POST['password'];
// Directly hash and store the password
$hashed_password = password_hash($password, PASSWORD_DEFAULT);

Patched Code (25.11.0): The patched version enforces a minimum password length and complexity.

// Patched: Password strength validation
$password = $_POST['password'];
if (strlen($password) < 8 || !preg_match('/[A-Z]/', $password) || !preg_match('/[a-z]/', $password) || !preg_match('/[0-9]/', $password)) {
    throw new Exception('Password must be at least 8 characters and contain uppercase, lowercase, and numeric characters.');
}
$hashed_password = password_hash($password, PASSWORD_DEFAULT);

Exploitation & Lab Setup

Red Team

Objective: Demonstrate the creation and exploitation of a weak account.

Prerequisites:

• Administrative access to a vulnerable LibreNMS instance (version < 25.11.0).
• Network access to the LibreNMS web interface.

Steps:

1. Log in as an administrator.
2. Navigate to the user management section.
3. Create a new user with a weak password (e.g., testuser / 12345678).
4. Log out and attempt to brute-force the weak account using a tool like Hydra:

   hydra -l testuser -P /usr/share/wordlists/rockyou.txt <target_ip> http-post-form "/login:username=^USER^&password=^PASS^:F=Invalid"
   

5. Once the password is cracked, log in as the weak user and access the system.

Blue Team

Objective: Detect and prevent the creation of weak accounts.

Detection:

• Monitor user creation logs for accounts with simple passwords.
• Use SIEM rules to alert on user creation events without password complexity checks.

Prevention:

• Immediately upgrade to LibreNMS version 25.11.0 or later.
• Implement additional password policy enforcement via a web application firewall (WAF) or custom middleware.
• Conduct regular audits of user accounts and their password strength.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Multiple failed login attempts from a single IP address (brute-force indicator).
  • Successful login from an IP address not in the allowed list.
• System IOCs:
  • User accounts with passwords that are common dictionary words or simple patterns (e.g., "12345678", "password").
  • Unusual user creation events in the application logs.
• File IOCs:
  • Log entries showing user creation without password validation (e.g., missing password_policy check).

Detection Engineering

YARA Rule

rule CVE_2025_65014_Weak_Password_Policy {
    meta:
        description = "Detects weak password policy in LibreNMS user creation"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-65014"
    strings:
        $weak_password = /password\s*=\s*['"][a-zA-Z0-9]{1,7}['"]/ nocase
        $no_validation = /password_hash\(\$password/
    condition:
        $weak_password and $no_validation
}

Sigma Rule

title: Weak Password Policy in LibreNMS User Creation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects creation of user accounts with weak passwords in LibreNMS
author: Valters IT
date: 2025-04-10
logsource:
    category: application
    product: librenms
detection:
    selection:
        event: user_created
        password_length|lt: 8
    condition: selection
falsepositives:
    - Legitimate accounts with short passwords (unlikely)
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-65014 - Weak Password Policy in LibreNMS"; flow:to_server,established; content:"POST"; http_method; content:"/users"; http_uri; content:"password"; http_client_body; pcre:"/password=[a-zA-Z0-9]{1,7}/"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade LibreNMS to version 25.11.0 or later.
2. Audit existing user accounts and enforce password changes for any accounts with weak passwords.
3. Implement multi-factor authentication (MFA) for all administrative accounts.

Long-term Measures:

• Enforce a strong password policy (minimum 12 characters, mixed case, numbers, special characters).
• Use a password manager to generate and store complex passwords.
• Regularly review user accounts and remove inactive or unnecessary accounts.
• Monitor logs for brute-force attempts and implement rate limiting on login endpoints.

Valters IT Signature

This report was generated by Valters IT DevSecOps & CTI Expert System.