How to remediate – Atlassian Crowd Detection

1. Introduction

Atlassian Crowd Detection identifies instances of Atlassian Crowd, a web-based single sign-on user identity tool running on remote web servers. This is important because Crowd can be vulnerable to attacks if not properly secured and patched. Affected systems are typically those using Java-based applications requiring centralised authentication. A successful exploit could compromise user identities and allow unauthorised access to connected services, impacting confidentiality, integrity, and availability.

2. Technical Explanation

Atlassian Crowd is a single sign-on (SSO) tool written in Java that manages user identities for applications. The vulnerability lies in the presence of the tool itself, as it represents an attack surface. An attacker could attempt to exploit known vulnerabilities within Crowd or use it as a pivot point for wider attacks on connected systems. There are no specific CVEs associated with simply *detecting* the presence of Crowd; however, its existence warrants investigation and patching against known issues.

• Root cause: The tool is installed and running, presenting an attack surface.
• Exploit mechanism: An attacker could attempt to exploit vulnerabilities in Atlassian Crowd itself or use it as a stepping stone for attacks on other systems.
• Scope: Systems running Atlassian Crowd software.

3. Detection and Assessment

Confirming the presence of Atlassian Crowd can be done through port scanning and banner grabbing, or by checking running Java processes. A thorough method involves inspecting web server configurations.

• Quick checks: Use netstat -tulnp | grep crowd to check for listening ports associated with Crowd.
• Scanning: Nessus plugin ID 16578 can detect Atlassian Crowd. This is an example only and may require updates.
• Logs and evidence: Check web server access logs for requests related to the Crowd application context (e.g., /crowd/).

netstat -tulnp | grep crowd

4. Solution / Remediation Steps

The primary remediation step is to ensure Atlassian Crowd is up-to-date with the latest security patches and configured securely. If Crowd is not required, it should be removed.

4.1 Preparation

• Ensure you have access to the Atlassian Crowd installation directory and configuration files. A rollback plan involves restoring from the snapshot.
• A change window may be required depending on the criticality of the system. Approval from the IT security team is recommended.

4.2 Implementation

1. Step 1: Check the current version of Atlassian Crowd using the web interface or command line tools.
2. Step 2: Download the latest version of Atlassian Crowd from the official Atlassian website.
3. Step 3: Back up the existing Crowd installation directory and configuration files.
4. Step 4: Install the new version of Atlassian Crowd, overwriting the old installation.
5. Step 5: Restore the backed-up configuration files to the new installation directory.
6. Step 6: Start the Atlassian Crowd service.

4.3 Config or Code Example

Before

#Example insecure config - default settings may be vulnerable
crowd.properties:
  crowd.default.password=changeme

After

#Secure config - strong password and secure connection
crowd.properties:
  crowd.default.password=
  crowd.https.enabled=true
  crowd.https.port=8443

4.4 Security Practices Relevant to This Vulnerability

Several security practices can help mitigate the risks associated with Atlassian Crowd. Least privilege reduces the impact of a successful attack, while regular patching ensures known vulnerabilities are addressed.

• Practice 1: Implement least privilege principles for all user accounts accessing Crowd.
• Practice 2: Establish a regular patch cadence to apply security updates promptly.

4.5 Automation (Optional)

#Example PowerShell script - requires Atlassian CLI tools
# This is an example and may require modification for your environment.
# Stop-Service -Name "Atlassian Crowd" -Force
# Install-PackageProvider -Name NuGet -Force
# Install-Module -Name AtlassianCrowd -Force
# Update-CrowdInstance -Version 

5. Verification / Validation

• Post-fix check: Run netstat -tulnp | grep crowd to confirm the service is running on the expected port. Check the web interface for the updated version number.
• Re-test: Re-run the initial detection method (e.g., Nessus scan) to verify the vulnerability is no longer detected.
• Smoke test: Verify users can still log in through Crowd without issues.
• Monitoring: Monitor web server logs for any errors related to Crowd authentication.

netstat -tulnp | grep crowd

6. Preventive Measures and Monitoring

Regularly update security baselines and incorporate vulnerability scanning into CI/CD pipelines to prevent similar issues in the future.

• Baselines: Update your security baseline to include a requirement for Crowd to be patched regularly.
• Asset and patch process: Implement a monthly review cycle for all critical software, including Atlassian Crowd.

7. Risks, Side Effects, and Roll Back

Updating Atlassian Crowd may cause temporary service disruption or compatibility issues with other applications. A rollback plan involves restoring the previous version from the snapshot.

• Risk or side effect 1: Service downtime during the update process. Mitigation: Schedule updates during off-peak hours.
• Roll back: Restore the server from the pre-update snapshot.

8. References and Resources

Link only to sources that match this exact vulnerability.

• Vendor advisory or bulletin: https://www.atlassian.com/software/crowd
• NVD or CVE entry: Not applicable for detection only.
• Product or platform documentation relevant to the fix: https://support.atlassian.com/crowd/