How to remediate – Default Password (alpine) for ‘mobile’ Account

1. Introduction

The ‘Default Password (alpine) for ‘mobile’ Account’ vulnerability means the ‘mobile’ account on affected systems is created with a weak default password (‘alpine’). This allows attackers to gain unauthorized access to the system without needing valid credentials. Affected systems typically include those running Alpine Linux, and iPhones are known to use these credentials by default when jailbroken. A successful exploit could compromise confidentiality, integrity, and availability of the system.

2. Technical Explanation

The vulnerability occurs because the ‘mobile’ account is shipped with a predictable default password. An attacker can attempt to log in using this known credential. This is particularly relevant on systems where SSH access is enabled. The CVE associated with this issue is CVE-1999-0502. For example, an attacker could use SSH to connect to the system and execute arbitrary commands if the ‘mobile’ account has sufficient privileges.

• Root cause: Use of a weak default password for the ‘mobile’ account.
• Exploit mechanism: An attacker attempts to log in using the username ‘mobile’ and the password ‘alpine’.
• Scope: Systems running Alpine Linux, iPhones (when jailbroken).

3. Detection and Assessment

You can check if a system is vulnerable by attempting to login with the default credentials. A thorough method involves auditing all accounts for weak or default passwords.

• Quick checks: Attempt to SSH into the target system using the username ‘mobile’ and password ‘alpine’.
• Scanning: Nessus vulnerability scan ID a8323342 may detect this issue (example only).
• Logs and evidence: Check authentication logs for successful logins with the ‘mobile’ account.

ssh mobile@<target_ip_address>

4. Solution / Remediation Steps

The following steps will fix the issue by setting a strong password for the affected account or disabling it.

4.1 Preparation

• Consider stopping SSH service if possible to prevent concurrent access during remediation. A roll back plan is to restore from the snapshot.
• Changes should be approved by the IT security team.

4.2 Implementation

1. Step 1: Change the password for the ‘mobile’ account using the `passwd` command.
2. Step 2: Verify that the new password is strong and meets your organization’s complexity requirements.

4.3 Config or Code Example

Before

# No password set, or default 'alpine'

After

passwd mobile
New password: <strong_password>
Re-type new password: <strong_password>

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help prevent this issue. Least privilege reduces the impact if an account is compromised. Safe defaults ensure accounts are not created with weak passwords. A regular patch cadence ensures systems have the latest security updates.

• Practice 1: Implement least privilege to limit the damage caused by a compromised account.
• Practice 2: Enforce strong password policies and require users to change default passwords immediately upon account creation.

4.5 Automation (Optional)

#!/bin/bash
# This script changes the password for the 'mobile' account on Alpine Linux systems.
# WARNING: Ensure you have appropriate permissions before running this script.
for host in <list_of_hosts>; do
  ssh root@${host} "passwd mobile"
done

5. Verification / Validation

• Post-fix check: Attempt to SSH into the target system using the username ‘mobile’ and the old password (‘alpine’). The login should fail.
• Re-test: Repeat the quick check from Section 3, which should now also fail.
• Smoke test: Verify that legitimate users can still log in with their correct credentials.
• Monitoring: Monitor authentication logs for failed login attempts using the ‘mobile’ account.

ssh mobile@<target_ip_address> # Should fail after password change

6. Preventive Measures and Monitoring

Update security baselines to include strong password policies. Implement checks in CI/CD pipelines to prevent the deployment of systems with default passwords. A regular patch or config review cycle can help identify and address vulnerabilities like this one.

• Baselines: Update your system hardening baseline to require changing default passwords on all accounts.
• Pipelines: Add a check in your CI/CD pipeline to scan for systems with default credentials.
• Asset and patch process: Review configurations regularly to ensure compliance with security policies.

7. Risks, Side Effects, and Roll Back

Changing the password may disrupt services if the ‘mobile’ account is used by other applications. Ensure you have a roll back plan in place.

• Risk or side effect 1: Changing the password could break existing integrations that rely on the default credentials.
• Risk or side effect 2: Incorrectly configured SSH access can lock out administrators.

8. References and Resources

• Vendor advisory or bulletin: No specific vendor advisory available for Alpine Linux default password.
• NVD or CVE entry: CVE-1999-0502
• Product or platform documentation relevant to the fix: Alpine Linux SSH Key Authentication