Executive Summary

This vulnerability exists in the nltk.app.wordnet_app up to version 3.9.3. It allows an unauthenticated remote attacker to shut down the local WordNet Browser HTTP server by sending a specific GET request (/SHUTDOWN%20THE%20SERVER). The server, which listens on all interfaces by default, processes this request and immediately terminates the process using os._exit(0).

The root cause is insufficient authentication and protection mechanisms for critical server functions, allowing anyone to remotely cause a denial of service by shutting down the server.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability can impact you by causing a denial of service (DoS) on the WordNet Browser HTTP server. Since the server can be remotely shut down without authentication, it can lead to service unavailability, disrupting any applications or services relying on this server.

Useful 0 Not Useful 0

Detection Guidance

This vulnerability can be detected by monitoring network traffic for unauthenticated GET requests to the WordNet Browser HTTP server, specifically requests targeting the path '/SHUTDOWN%20THE%20SERVER'. Since the server listens on all interfaces, scanning for open HTTP ports where nltk.app.wordnet_app is running may help identify vulnerable instances.

A possible command to detect the presence of the vulnerable server is to use curl or wget to send the shutdown request and observe the server response or termination:

• curl -v http://<target-ip>:<port>/SHUTDOWN%20THE%20SERVER
• wget --spider http://<target-ip>:<port>/SHUTDOWN%20THE%20SERVER

If the server process terminates or the connection is closed immediately, it indicates the vulnerability is present.

Useful 0 Not Useful 0

Mitigation Strategies

Immediate mitigation steps include restricting access to the WordNet Browser HTTP server by limiting network exposure, such as binding the server to localhost only or using firewall rules to block external access.

Additionally, avoid running the vulnerable version of nltk.app.wordnet_app (up to 3.9.3) in default mode where it listens on all interfaces without authentication.

If possible, update to a patched version of the software once available or implement authentication and access controls to prevent unauthenticated shutdown requests.

Useful 0 Not Useful 0

Compliance Impact

This vulnerability allows unauthenticated remote shutdown of the WordNet Browser HTTP server, resulting in denial of service and impacting service availability.

Since the vulnerability affects availability, it could potentially impact compliance with standards and regulations that require maintaining service availability, such as HIPAA and GDPR.

However, there is no direct information provided about data confidentiality or integrity being compromised, so the impact on compliance related to data protection requirements is unclear.

Useful 0 Not Useful 0