1. Introduction
IBM Lotus Sametime Server contains a cross-site scripting (XSS) vulnerability in the ‘stconf.nsf’ script due to improper input sanitization of the ‘messageString’ parameter. This allows an attacker to inject malicious scripts into web pages viewed by users, potentially leading to session hijacking, data theft, or defacement. Affected systems are typically those running Lotus Sametime Server versions prior to a fix being applied. Successful exploitation could compromise confidentiality, integrity and availability of user sessions and associated data.
2. Technical Explanation
- Root cause: Missing input validation on the ‘messageString’ parameter of the ‘stconf.nsf’ script.
- Exploit mechanism: An attacker crafts a URL with malicious JavaScript in the ‘messageString’ parameter and sends it to a victim. When the victim opens the link, the script executes within their browser context. For example, a URL could contain .
- Scope: Lotus Sametime Server versions are affected. The stcenter.nsf script may also be vulnerable but was not tested in this assessment.
3. Detection and Assessment
To confirm vulnerability, check the version of Lotus Sametime running on the server. Thorough assessment involves attempting to inject a simple XSS payload.
- Quick checks: Use the command line or web interface to determine the installed version of Lotus Sametime Server.
- Scanning: Nessus plugin ID 516563 can detect this vulnerability, but results should be verified manually.
- Logs and evidence: Examine server logs for requests containing suspicious JavaScript code in the ‘messageString’ parameter. The specific log file location varies depending on the Lotus Sametime Server configuration.
4. Solution / Remediation Steps
Apply a patch released by IBM to address this vulnerability. As of the current information, no specific solution is available.
4.1 Preparation
- Ensure you have access to the latest patches from IBM’s support website. A roll back plan involves restoring the backed-up configuration and restarting the services.
- A change window may be required depending on your organization’s policies. Approval from a security team or system owner is recommended.
4.2 Implementation
- Step 1: Download the latest patch for Lotus Sametime Server from IBM’s support website.
- Step 2: Install the downloaded patch following IBM’s official installation instructions.
4.3 Config or Code Example
Before
After
4.4 Security Practices Relevant to This Vulnerability
Implementing input validation and using a patch cadence can help prevent this issue.
- Practice 2: Maintain a regular patch cadence for Lotus Sametime Server and other software components to address known vulnerabilities promptly.
4.5 Automation (Optional)
5. Verification / Validation
Confirm the patch installation by checking the version number. Re-test for XSS vulnerability and perform basic service smoke tests.
- Post-fix check: Verify that the Lotus Sametime Server version has been updated to a patched release.
- Smoke test: Log in to the Lotus Sametime Server web interface and verify basic functionality, such as sending messages and accessing contacts.
- Monitoring: Monitor server logs for any unexpected errors or suspicious activity related to input validation.
6. Preventive Measures and Monitoring
Update security baselines, implement checks in CI/CD pipelines, and maintain a sensible patch review cycle.
- Baselines: Update your Lotus Sametime Server security baseline to include the latest patches and configuration settings.
- Pipelines: Integrate static application security testing (SAST) tools into your CI/CD pipeline to identify potential XSS vulnerabilities during development.
- Asset and patch process: Establish a regular review cycle for new patches released by IBM, aiming to apply critical updates within a defined timeframe.
7. Risks, Side Effects, and Roll Back
Applying the patch may cause temporary service disruption. A roll back plan involves restoring the backed-up configuration.
- Risk or side effect 1: Patch installation might temporarily interrupt Lotus Sametime Server services.
- Risk or side effect 2: In rare cases, a patch could introduce compatibility issues with other applications.
- Roll back: Restore the pre-patch configuration from the backup and restart the Lotus Sametime Server services.
8. References and Resources
- Vendor advisory or bulletin: https://www.securityfocus.com/archive/1/516563
- NVD or CVE entry: CVE-2011-1038
- Product or platform documentation relevant to the fix: No specific documentation available at this time.