How to remediate – Zabbix Web Interface Default Administrator Credentials

1. Introduction

The Zabbix Web Interface Default Administrator Credentials vulnerability means the web application uses a standard username and password (‘Admin’ / ‘zabbix’) to manage it. This is a security risk because anyone can gain full control of the system with these details. Systems running the Zabbix monitoring platform are usually affected, particularly those newly installed or without updated configurations. A successful attack could compromise confidentiality, integrity, and availability of monitored systems and the Zabbix server itself.

2. Technical Explanation

The vulnerability occurs because Zabbix ships with a default administrator account that is not changed during installation. An attacker can use these credentials to log in to the web interface and take complete control. There are no specific CVEs currently associated with this issue, but it falls under CWE-798 (Use of Hardcoded Credentials). A simple example would be an attacker attempting to login using ‘Admin’ as the username and ‘zabbix’ as the password from the Zabbix web interface login page.

• Root cause: The use of default, publicly known credentials for administrative access.
• Exploit mechanism: An attacker attempts to log in to the Zabbix Web Interface using the default username and password combination (‘Admin’ / ‘zabbix’). If successful, they gain full administrative control.
• Scope: All versions of Zabbix with the default credentials enabled are affected.

3. Detection and Assessment

• Quick checks: Access the Zabbix Web Interface login page and attempt to log in using ‘Admin’ as the username and ‘zabbix’ as the password.
• Scanning: Nessus plugin ID 16084 or OpenVAS scanner family “Web Application Default Credentials” may detect this issue, but results should be verified manually.
• Logs and evidence: Check Zabbix server logs for successful login attempts from the default ‘Admin’ account. The log file is typically located at /var/log/zabbix/zabbix_server.log.

curl -I http://your-zabbix-server/ | grep Server

4. Solution / Remediation Steps

The solution is to change the default login credentials for the Zabbix Web Interface. Follow these steps carefully.

4.1 Preparation

• Ensure you have access to the Zabbix database (usually MySQL or PostgreSQL). A roll back plan involves restoring the database from the backup if needed.
• A change window may be required, depending on your environment and downtime tolerance. Approval from a system owner might be necessary.

4.2 Implementation

1. Step 1: Log in to the Zabbix database as an administrator user.
2. Step 2: Execute the following SQL query to change the password for the ‘Admin’ user: UPDATE users SET passwd = MD5('your_new_password') WHERE alias = 'Admin'; Replace ‘your_new_password’ with a strong, unique password.
3. Step 3: Restart the Zabbix server service to apply the changes.

4.3 Config or Code Example

Before

SELECT alias, passwd FROM users WHERE alias = 'Admin'; -- Shows default password hash

After

SELECT alias, passwd FROM users WHERE alias = 'Admin'; -- Shows new password hash after update.

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this type of issue. Least privilege reduces the impact if an account is compromised. Safe defaults mean systems should not ship with easily guessed credentials. Regular patch cadence ensures known vulnerabilities are addressed quickly.

• Practice 1: Implement least privilege principles, limiting administrative access to only those who require it.
• Practice 2: Enforce strong password policies and regular password changes for all accounts.

4.5 Automation (Optional)

#!/bin/bash
# Example Bash script to change Zabbix Admin password (requires database access)
DB_USER="your_db_user"
DB_PASS="your_db_password"
DB_NAME="zabbix"
NEW_PASSWORD="your_new_password"
mysql -u "$DB_USER" -p"$DB_PASS" -D "$DB_NAME" -e "UPDATE users SET passwd = MD5('$NEW_PASSWORD') WHERE alias = 'Admin';"
echo "Zabbix Admin password updated."

5. Verification / Validation

• Post-fix check: Access the Zabbix Web Interface login page and attempt to log in using ‘Admin’ as the username and ‘zabbix’ as the password. Expected output: Login failed.
• Re-test: Repeat the quick check from section 3, which should no longer succeed with default credentials.
• Monitoring: Monitor Zabbix server logs for failed login attempts using ‘Admin’ as a username to detect potential brute-force attacks.

grep "Login failed" /var/log/zabbix/zabbix_server.log

6. Preventive Measures and Monitoring

Update security baselines to include checks for default credentials. Implement CI/CD pipeline checks to prevent deployments with insecure configurations. Establish a regular patch or configuration review cycle.

• Baselines: Update your security baseline to include a check for the Zabbix Admin password being changed from the default value.
• Pipelines: Add a static analysis step in your CI/CD pipeline to scan Zabbix configurations for hardcoded credentials or default settings.
• Asset and patch process: Implement a monthly review of Zabbix configuration files to ensure compliance with security standards.

7. Risks, Side Effects, and Roll Back

• Risk or side effect 1: Incorrect SQL syntax can cause database errors. Mitigation: Test the query in a non-production environment first.
• Risk or side effect 2: Forgetting the new password could lead to service disruption. Mitigation: Document the new password securely.
• Roll back:
  1. Step 2: Restart the Zabbix server service.

8. References and Resources

• Vendor advisory or bulletin: Zabbix Documentation – Security Considerations
• NVD or CVE entry: No