1. Introduction
The Alcatel ADSL Modem Unrestricted Remote Access vulnerability allows unauthenticated access to the modem’s management interface. This means an attacker on the network, or even remotely over the internet, could change settings and potentially compromise your network. Affected systems are typically Alcatel Speed Touch Pro ADSL modems where remote access protection is not enabled. A successful exploit could lead to loss of confidentiality, integrity, and availability of network services.
2. Technical Explanation
The vulnerability stems from a disabled security feature on the modem that prevents remote access via the WAN/DSL interface. By default, this protection is not activated, allowing anyone with network access to connect using Telnet without authentication. An attacker can then modify settings or gain further control of the device. This issue is tracked as CVE-2001-1424.
- Root cause: The remote management interface is enabled by default without password protection.
- Exploit mechanism: An attacker uses Telnet to connect to the modem’s IP address and gains access to the configuration menu without a username or password.
- Scope: Alcatel Speed Touch Pro ADSL modems with unconfigured security settings are affected.
3. Detection and Assessment
You can confirm if your system is vulnerable by checking the remote management status and default credentials. A quick check involves attempting to connect via Telnet without a password.
- Quick checks: Attempt to Telnet to the modem’s IP address without providing any login details. If successful, the system is likely vulnerable.
- Scanning: Nessus plugin ID 16859 can detect this vulnerability. This is an example only and may require updates.
- Logs and evidence: Check modem logs for Telnet connections from unknown sources or failed authentication attempts (if any logging is enabled).
telnet <modem_ip_address>4. Solution / Remediation Steps
These steps will enable firewalling and set a strong password on the modem to secure it.
4.1 Preparation
- There are no dependencies or pre-requisites for this fix. Changes should be performed during a maintenance window.
4.2 Implementation
- Step 1: Telnet to the modem’s IP address.
- Step 2: Enter the following command to enable firewalling:
ip config firewalling on - Step 3: Save the configuration using the command:
config save - Step 4: Set a strong password for all accounts. The exact commands vary depending on your modem’s firmware version, but typically involve accessing account settings via the CLI or web interface.
4.3 Config or Code Example
Before
# No firewall enabled, default credentials in placeAfter
ip config firewalling on
config save
# Strong password set for all accounts (command varies by firmware)4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent this issue.
- Practice 1: Least privilege – Limit access to the modem’s configuration interface to only authorized personnel.
4.5 Automation (Optional)
Automation is not recommended for this specific vulnerability due to the risk of misconfiguration. Manual verification is essential.
5. Verification / Validation
Confirm that firewalling is enabled and you can no longer connect via Telnet without a password.
- Post-fix check: Attempt to Telnet to the modem’s IP address again. You should now be prompted for a username and password.
- Re-test: Repeat the quick check from section 3. The connection attempt should fail without valid credentials.
- Monitoring: Monitor modem logs for failed Telnet attempts, which could indicate ongoing reconnaissance activity.
telnet <modem_ip_address> # Should now prompt for username and password6. Preventive Measures and Monitoring
Regular security assessments and a robust patch management process can help prevent similar vulnerabilities.
- Baselines: Include modem configuration settings in your security baseline, ensuring firewalling is enabled and strong passwords are used.
- Pipelines: Consider using automated configuration management tools to enforce consistent security settings across all modems.
- Asset and patch process: Review modem firmware regularly for updates and apply them promptly.
7. Risks, Side Effects, and Roll Back
Incorrectly configuring the firewall could disrupt internet connectivity.
- Roll back: Power cycle the modem to revert to its default settings, but this will lose any custom configurations made.
8. References and Resources
- Vendor advisory or bulletin: http://www.alcatel.com/consumer/dsl/security.htm
- NVD or CVE entry: CVE-2001-1424
- Product or platform documentation relevant to the fix: Refer to your Alcatel Speed Touch Pro ADSL modem’s user manual for specific configuration instructions.