1. Introduction
The Allaire JRun Encoded JSP Request Directory Listing vulnerability affects web servers running Allaire JRun. This information disclosure flaw allows unauthenticated attackers to view files in arbitrary directories, potentially exposing sensitive data. Systems running vulnerable versions of JRun are at risk. Confidentiality is the primary impact, with a potential for moderate data exposure.
2. Technical Explanation
The vulnerability occurs due to improper handling of malformed URLs within Allaire JRun. An attacker can craft a specific request that bypasses normal access controls and displays directory listings. This requires no authentication. The CVE associated with this issue is CVE-2001-1510. A simple example involves sending a crafted URL containing encoded characters to trigger the listing of files in an unintended directory. Affected versions are those susceptible to the flawed URL parsing logic.
- Root cause: JRun fails to properly sanitize or validate URLs, allowing for path traversal and directory listing requests.
- Exploit mechanism: An attacker sends a specially crafted HTTP request with encoded characters in the URL to access files outside of the intended web root.
- Scope: Allaire JRun versions prior to those patched against CVE-2001-1510 are affected.
3. Detection and Assessment
You can confirm vulnerability by checking your JRun version. A thorough assessment involves attempting to access restricted directories via a crafted URL.
- Quick checks: Use the JRun administration console or command-line tools to determine the installed JRun version.
- Scanning: Nessus plugin ID 16850 may detect this vulnerability as an example.
- Logs and evidence: Examine web server logs for requests containing unusual URL encoding patterns or attempts to access files outside of the expected web root directory.
# Example command placeholder:
# No specific command available, check JRun version via admin console.
4. Solution / Remediation Steps
Disable directory browsing in your applications to mitigate this vulnerability. Refer to the security advisory for detailed steps.
4.1 Preparation
- There are no specific dependencies, but ensure you have access to the JRun administration console or configuration files. Change windows may be required depending on service impact.
4.2 Implementation
- Step 1: Access the JRun administration console.
- Step 2: Navigate to the application settings for each web application.
- Step 3: Disable directory browsing within the application configuration. This is typically a checkbox or setting labelled “Directory Listing” or similar.
- Step 4: Save the changes and restart the affected web applications.
4.3 Config or Code Example
Before
<web-app ...>
<servlet>
<init-param><param-name>options</param-name>
<param-value>listing=true</param-value>
</init-param>
</servlet>
</web-app>After
<web-app ...>
<servlet>
<init-param><param-name>options</param-name>
<param-value>listing=false</param-value>
</init-param>
</servlet>
</web-app>4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent this type of issue. Least privilege reduces the impact if exploited, while input validation blocks unsafe data and secure defaults minimize attack surfaces.
- Practice 1: Least privilege – limit user access to only necessary resources.
4.5 Automation (Optional)
No automation script is provided as configuration changes vary significantly between JRun deployments.
5. Verification / Validation
- Post-fix check: Attempt to access a known restricted directory via your web browser; expect a 403 Forbidden or similar error.
- Re-test: Repeat the earlier detection attempt (crafted URL) and confirm that it no longer displays a file listing.
# Post-fix command and expected output
# Attempting to access /admin via browser should return 403 Forbidden.
6. Preventive Measures and Monitoring
Update security baselines to include directory browsing restrictions. Implement regular vulnerability scanning in CI/CD pipelines. Establish a patch or configuration review cycle that fits the risk profile of your systems. For example, regularly scan for misconfigurations using automated tools.
- Baselines: Update security policies and CIS controls to enforce disabling directory listing by default.
- Pipelines: Add checks in CI/CD pipelines to identify applications with directory browsing enabled.
- Asset and patch process: Implement a monthly review of JRun configurations for compliance with security standards.
7. Risks, Side Effects, and Roll Back
Disabling directory browsing may affect some legacy applications that rely on it. The roll back steps involve re-enabling directory browsing in the application configuration and restarting the web application.
- Risk or side effect 2: Users accustomed to directory browsing may experience a change in functionality.
- Roll back: Step 1: Access the JRun administration console. Step 2: Re-enable directory browsing within the application configuration. Step 3: Save changes and restart affected web applications.
8. References and Resources
- Vendor advisory or bulletin: http://www.securityfocus.com/advisories/3689
- NVD or CVE entry: CVE-2001-1510