1. Introduction
The IBM WebSphere Portal ‘FilterForm.jsp’ vulnerability (PI15690) is a cross-site scripting (XSS) flaw affecting web portal software on Windows hosts. An attacker can inject malicious code into the application, potentially stealing user authentication cookies and gaining unauthorized access. This impacts confidentiality of user sessions and could lead to account compromise.
2. Technical Explanation
The vulnerability stems from improper validation of user input in the ‘FilterForm.jsp’ script within IBM WebSphere Portal. An attacker can craft a malicious URL containing XSS payloads that are then executed by a victim’s browser when they access the affected portal. This allows an attacker to execute code in the context of the user, potentially stealing cookies or performing actions on their behalf.
- Root cause: Insufficient input validation within the ‘FilterForm.jsp’ script.
- Exploit mechanism: An attacker crafts a URL with a malicious JavaScript payload embedded in a parameter that is not properly sanitized before being displayed to users. For example, an attacker could send a link like
http://example.com/portal/somepage?param= - Scope: IBM WebSphere Portal versions 7.0.0.2 CF28 (PI10705) and 8.0.0.1 CF12 (PI14791) are affected.
3. Detection and Assessment
To confirm vulnerability, check the installed version of IBM WebSphere Portal. Thorough assessment involves scanning for XSS vulnerabilities in web applications.
- Quick checks: Use the IBM Installation Manager to verify the portal version.
- Scanning: Nessus plugin ID 4e5ca5ae can detect this vulnerability. This is an example only; other scanners may also be suitable.
- Logs and evidence: Examine web server logs for suspicious requests containing JavaScript code in URL parameters.
4. Solution / Remediation Steps
Apply Interim Fix PI15690 published by IBM to address the vulnerability. Follow these steps for safe implementation.
4.1 Preparation
- Ensure you have sufficient disk space and network bandwidth to download and install the fix. A roll back plan involves restoring from the backup created in the previous step.
4.2 Implementation
- Step 1: Download Interim Fix PI15690 from IBM Support (http://www-01.ibm.com/support/docview.wss?uid=swg21672572).
- Step 2: Install the fix using the IBM Installation Manager. Follow the on-screen instructions to complete the installation.
4.3 Config or Code Example
Before
After
4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent XSS vulnerabilities. These include input validation, least privilege and a robust patch management process.
- Practice 2: Least privilege – Configure WebSphere Portal with the minimum necessary permissions to reduce the impact of a successful XSS attack.
4.5 Automation (Optional)
5. Verification / Validation
- Post-fix check: Use IBM Installation Manager to confirm that Interim Fix PI15690 has been successfully applied.
- Re-test: Attempt to exploit the vulnerability with a similar URL used for detection (e.g.,
http://example.com/portal/somepage?param=). The payload should not execute. - Smoke test: Verify that core WebSphere Portal functionality, such as user login and content display, continues to work as expected.
- Monitoring: Monitor web server logs for any suspicious requests containing JavaScript code in URL parameters.
6. Preventive Measures and Monitoring
Update security baselines to include the patched version of WebSphere Portal. Implement regular vulnerability scanning and penetration testing to identify potential XSS flaws.
- Baselines: Update your security baseline or policy to require Interim Fix PI15690 for all IBM WebSphere Portal installations.
- Pipelines: Incorporate SAST (Static Application Security Testing) tools into the CI/CD pipeline to detect XSS vulnerabilities during development.
- Asset and patch process: Establish a regular patch review cycle to ensure timely application of security updates, including those for IBM WebSphere Portal.
7. Risks, Side Effects, and Roll Back
- Risk or side effect 1: Brief service interruption during patch installation and server restart.
- Risk or side effect 2: Potential compatibility issues with custom portal extensions; test thoroughly in a non-production environment first.
8. References and Resources
- Vendor advisory or bulletin: IBM Security Bulletin
- NVD or CVE entry: CVE-2014-0951
- Product or platform documentation relevant to the fix: IBM WebSphere Portal Documentation.