1. Introduction
The Aruba ClearPass Policy Manager Detection vulnerability allows an attacker to obtain the operating system version number of a remote device. This information can be used for reconnaissance, aiding in targeted attacks by identifying specific vulnerabilities present on the system. Affected systems are typically network access control devices running Aruba Clearpass software, potentially impacting confidentiality through exposure of OS details.
2. Technical Explanation
The vulnerability stems from the ability to read the operating system version number via SSH login to the ClearPass Policy Manager device. An attacker with SSH access can directly query the system for this information. There is no known CVE associated with this specific issue, but it represents a basic information disclosure risk. A simple example of exploitation involves logging into the ClearPass device using valid credentials and executing commands that reveal OS details.
- Root cause: The OS version number can be read via SSH access to the device.
- Exploit mechanism: An attacker logs in with valid credentials, then executes a command to display the OS version.
- Scope: Aruba Networks (HP) Clearpass Policy Manager devices are affected.
3. Detection and Assessment
To confirm vulnerability, check if SSH access is enabled and whether the OS version can be retrieved. A thorough method involves attempting to connect via SSH and querying system information.
- Quick checks: Verify SSH service status using a command like
systemctl status ssh(if applicable). - Scanning: Nessus vulnerability ID 82e11f10 can be used as an example to identify the issue.
- Logs and evidence: Check system logs for successful SSH login attempts.
ssh <username>@<clearpass_ip>4. Solution / Remediation Steps
The following steps outline how to mitigate the risk of OS version disclosure. These steps focus on limiting SSH access and monitoring for unauthorized logins.
4.1 Preparation
- Dependencies: Ensure you have valid administrative credentials to access the ClearPass device via SSH. Rollback plan is to restore from backup if issues occur.
4.2 Implementation
- Step 1: Disable SSH access if not required for administration.
- Step 2: If SSH access is necessary, restrict it to specific IP addresses or networks using firewall rules.
- Step 3: Implement strong password policies and multi-factor authentication for all administrative accounts.
4.3 Config or Code Example
Before
# SSH enabled with default settings (example)
PermitRootLogin yes
PasswordAuthentication yes
After
# SSH access restricted and secured (example)
PermitRootLogin no
PasswordAuthentication no
AllowUsers <specific_user>
4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent this issue. Least privilege limits the impact of compromised accounts, while strong authentication reduces unauthorized access. Input validation is not directly applicable here, but secure defaults and a regular patch cadence are beneficial for overall system security.
- Practice 1: Implement least privilege to reduce the potential damage from a compromised account.
- Practice 2: Enforce strong password policies and multi-factor authentication on all administrative accounts.
4.5 Automation (Optional)
# Example Ansible snippet to disable SSH access
- name: Disable SSH service
service:
name: sshd
state: stopped
enabled: false
5. Verification / Validation
Confirm the fix by verifying that SSH access is disabled or restricted as configured. Re-test by attempting to connect via SSH from an unauthorized host. Perform a basic service smoke test to ensure core functionality remains operational.
- Post-fix check: Attempt to SSH into the ClearPass device from an unapproved IP address; connection should be refused.
- Re-test: Run the initial SSH access check and confirm it no longer reveals OS version information.
- Smoke test: Verify that web interface login and network access control functions are still working as expected.
ssh <username>@<clearpass_ip> (should fail if SSH is disabled or restricted)6. Preventive Measures and Monitoring
Update security baselines to include restrictions on SSH access. Implement checks in CI/CD pipelines to ensure secure configurations are deployed. Establish a regular patch review cycle to address known vulnerabilities promptly.
- Baselines: Update your security baseline or policy to enforce restricted SSH access and strong authentication.
- Pipelines: Add configuration validation checks to your CI/CD pipeline to prevent insecure SSH settings from being deployed.
- Asset and patch process: Review and apply security patches regularly, prioritizing those addressing remote access vulnerabilities.
7. Risks, Side Effects, and Roll Back
Disabling SSH may disrupt existing administrative workflows if it is the only method of access. Restricting SSH to specific IPs could impact legitimate users if not properly configured. To roll back, re-enable SSH with the original settings from your backup.
- Risk or side effect 1: Disabling SSH might require alternative remote access methods.
- Risk or side effect 2: Incorrectly restricting SSH IPs could block legitimate administrative access.
- Roll back: Restore the ClearPass Policy Manager from the pre-change backup.
8. References and Resources
- Vendor advisory or bulletin: http://www.nessus.org/u?82e11f10