How to remediate – 3Com Switch Default Admin Credentials

1. Introduction

The 3Com Switch Default Admin Credentials vulnerability allows unauthorized access to a 3Com switch due to the use of pre-set default login credentials. This can allow attackers to gain full control of network devices, potentially leading to data breaches, denial of service, or man-in-the-middle attacks. Systems affected are typically 3Com switches with unchanged default settings. A successful exploit could compromise confidentiality, integrity and availability of the network segment connected to the switch.

2. Technical Explanation

The vulnerability stems from 3Com switches shipping with well-known default usernames and passwords. An attacker who can connect to the switch’s management interface – typically via Telnet or SSH – can use these credentials to log in without authentication. There is no CVE associated with this specific issue, as it’s a configuration problem rather than a software flaw. A simple example would be an attacker using ‘admin’ and ‘password’ (or similar default combinations) to access the switch’s command line interface.

• Root cause: Use of hardcoded, default credentials on network devices.
• Exploit mechanism: An attacker attempts to log in to the switch management interface using common default username/password combinations. If successful, they gain administrative access.
• Scope: 3Com switches with default credentials enabled. Specific models are not known from this context.

3. Detection and Assessment

• Quick checks: Attempt login via Telnet or SSH with username ‘admin’ and password ‘password’.
• Scanning: Nmap can be used to identify open ports 23 (Telnet) and 22 (SSH). Nessus plugin ID 10459 may also detect this vulnerability. These are examples only.
• Logs and evidence: Check switch logs for successful logins from unknown sources or failed login attempts with default credentials. Log locations vary by model.

telnet <switch_ip>

4. Solution / Remediation Steps

The solution involves logging into the remote host and changing the default login credentials. This is a straightforward process, but requires careful execution to avoid locking yourself out of the device.

4.1 Preparation

• Services: No services need to be stopped for this remediation.
• Roll back: If you lose access, a factory reset may be required (consult the switch documentation).

4.2 Implementation

1. Step 1: Log in to the switch using existing credentials (if known) or default credentials if necessary.
2. Step 2: Navigate to the administration or security settings menu. The exact path varies by model, but typically involves commands like ‘configure terminal’ followed by password change options.
3. Step 3: Change both the username and password for all administrative accounts. Use strong, unique passwords.
4. Step 4: Save the configuration to persistent storage using a command such as ‘write memory’.

4.3 Config or Code Example

Before

enable
configure terminal
username admin password password
exit
write memory

After

enable
configure terminal
no username admin password password
username new_admin new_password
exit
write memory

4.4 Security Practices Relevant to This Vulnerability

Several security practices directly address this vulnerability type. Least privilege reduces the impact of a compromised account, while safe defaults prevent initial exposure.

• Practice 1: Implement least privilege by granting only necessary access rights to administrative accounts.
• Practice 2: Enforce strong password policies and regular password changes.

4.5 Automation (Optional)

Automation is difficult without specific switch APIs, but configuration management tools can be used to enforce password complexity rules.

# Example Ansible task - requires appropriate modules for 3Com switches
- name: Change default switch password
  ansible.builtin.command: "configure terminal; no username admin password password; username new_admin new_password; write memory"
  delegate_to: <switch_ip>

5. Verification / Validation

• Post-fix check: Attempt login via Telnet or SSH with username ‘admin’ and password ‘password’. Expected output should be “Invalid username or password”.
• Re-test: Repeat the quick checks from section 3; default credentials should no longer grant access.
• Smoke test: Verify basic network connectivity by pinging devices on the network segment connected to the switch.

telnet <switch_ip>

6. Preventive Measures and Monitoring

Update security baselines to include strong password requirements for all network devices. Implement a patch or configuration review cycle to identify and address default credentials promptly.

• Baselines: Update your network device baseline to require unique, complex passwords on all switches.
• Pipelines: Incorporate automated checks in CI/CD pipelines to scan for hardcoded credentials in switch configurations.
• Asset and patch process: Review switch configurations regularly (e.g., quarterly) to ensure default credentials have not been re-enabled.

7. Risks, Side Effects, and Roll Back

• Risk or side effect 1: Incorrect configuration can lead to loss of switch access. Mitigation: Document all changes and test thoroughly.
• Roll back: If you lose access, consult the switch documentation for factory reset instructions. This will erase the current configuration.

8. References and Resources

• Vendor advisory or bulletin: No specific vendor advisory available for this general issue.
• NVD or CVE entry: No specific CVE associated with default credentials on 3Com switches.
• Product or platform documentation relevant to the fix: Consult the 3Com switch model-specific configuration guide for password change instructions.