How to remediate – Alcatel OmniSwitch Default Credentials (telnet)

1. Introduction

The Alcatel OmniSwitch Default Credentials (telnet) vulnerability allows access to remote devices using factory-set usernames and passwords. This poses a risk to business operations as attackers can gain full administrative control of network switches, potentially disrupting services, stealing sensitive data, or modifying configurations. Systems affected are Alcatel OmniSwitches that have not had their default credentials changed. A successful exploit could compromise confidentiality, integrity, and availability.

2. Technical Explanation

The vulnerability stems from the use of hardcoded default credentials on Alcatel OmniSwitch devices. An attacker can remotely connect to the switch via telnet using these credentials without authentication. This allows them to execute commands with administrative privileges. There is no known CVE associated with this specific issue, but it falls under CWE-798 (Use of Hard-coded Credentials). For example, an attacker could use a simple telnet client and attempt to log in with the default username ‘admin’ and password ‘admin’. Affected devices include those running firmware versions that retain these default settings.

• Root cause: The OmniSwitch ships with pre-configured credentials that are not changed during initial setup.
• Exploit mechanism: An attacker uses a telnet client to connect to the switch and attempts login using default credentials. Successful login grants administrative access.
• Scope: Alcatel OmniSwitches running firmware versions with default credentials enabled.

3. Detection and Assessment

To confirm vulnerability, first check if telnet is enabled on the device. Then attempt to log in using the default credentials. For a thorough assessment, review switch configurations for any instances of hardcoded passwords or weak authentication settings.

• Quick checks: Use the show ip interface brief command via SSH to check if telnet is enabled on an interface.
• Scanning: Nessus plugin ID 10428 can identify default credentials on Alcatel devices (example only).
• Logs and evidence: Examine switch logs for failed login attempts using the ‘admin’ username, which may indicate brute-force attacks targeting default credentials.

show ip interface brief

4. Solution / Remediation Steps

The primary solution is to change the default password on the Alcatel OmniSwitch or disable telnet access altogether. These steps are small, testable and safe to roll back.

4.1 Preparation

• Dependencies: Access to the switch via SSH or console port. Rollback plan: Restore the backed-up configuration if issues occur.
• Change windows may be needed during peak hours, requiring approval from network administrators.

4.2 Implementation

1. Step 1: Connect to the switch using SSH or the console port.
2. Step 2: Enter configuration mode by typing configure terminal.
3. Step 3: Change the password for the ‘admin’ user using the command password .
4. Step 4: Save the configuration using the command write memory or copy running-config startup-config.

4.3 Config or Code Example

Before

admin
admin

After

password 

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this type of vulnerability. Least privilege reduces the impact if an account is compromised, and strong password policies enforce secure credentials. Safe defaults ensure systems are not shipped with easily guessable settings.

• Practice 1: Implement least privilege to limit access rights for all users, reducing potential damage from a compromised account.
• Practice 2: Enforce strong password policies requiring complex passwords and regular changes.

4.5 Automation (Optional)

Automation is not recommended for this specific task due to the risk of misconfiguration. Manual configuration change is preferred.

5. Verification / Validation

• Post-fix check: Attempt to telnet into the switch using ‘admin’ and the old password. The connection should be refused or authentication should fail.
• Re-test: Repeat the quick check from Section 3, attempting login with default credentials; it should now fail.
• Smoke test: Ping a known host on the network to confirm basic connectivity is still working.
• Monitoring: Monitor switch logs for failed login attempts using ‘admin’ or other common usernames.

Attempt telnet connection with default credentials - Connection refused.

6. Preventive Measures and Monitoring

Regular security baselines should include checks for default credentials on network devices. Implement CI/CD pipelines to scan configurations for hardcoded passwords or weak settings during deployment. A sensible patch review cycle helps ensure timely updates.

• Baselines: Update a security baseline to include a check for default credentials and strong password requirements on all network devices.
• Asset and patch process: Implement a regular review cycle (e.g., monthly) to assess and update device configurations and firmware.

7. Risks, Side Effects, and Roll Back

Changing the password incorrectly could lock you out of the switch. Always have console access available as a backup. Rolling back involves restoring the backed-up configuration.

• Risk or side effect 1: Incorrect password entry may result in temporary lockout; use console access for recovery.
• Risk or side effect 2: Configuration errors could disrupt network connectivity; have a rollback plan ready.
• Roll back: Restore the backed-up configuration file using the switch’s restore command.

8. References and Resources

Links to official advisories and trusted documentation related to this vulnerability.

• Vendor advisory or bulletin: Alcatel Enterprise Support Documentation
• NVD or CVE entry: No specific CVE is available for this issue.
• Product or platform documentation relevant to the fix: Alcatel OmniSwitch Configuration Guides