CVE-2020-13697 : Vulnerability Insights and Analysis

An issue was discovered in RouterNanoHTTPD.java in NanoHTTPD through 2.3.1. The GeneralHandler class implements a basic GET handler that prints debug information as an HTML page. Any web server that extends this class without implementing its own GET handler is vulnerable to reflected XSS, because the GeneralHandler GET handler prints user input passed through the query string without any sanitization.

Understanding CVE-2020-13697

This CVE identifies a vulnerability in NanoHTTPD through version 2.3.1 that can lead to reflected XSS attacks.

What is CVE-2020-13697?

The vulnerability arises from the GeneralHandler class in RouterNanoHTTPD.java, which lacks proper sanitization of user input passed through the query string, making servers susceptible to reflected XSS attacks.

The Impact of CVE-2020-13697

The vulnerability allows attackers to execute malicious scripts in the context of a user's session, potentially leading to unauthorized actions or data theft.

Technical Details of CVE-2020-13697

NanoHTTPD through version 2.3.1 is affected by this vulnerability.

Vulnerability Description

The GeneralHandler class in RouterNanoHTTPD.java fails to sanitize user input from the query string, enabling attackers to inject and execute malicious scripts.

Affected Systems and Versions

Product: NanoHTTPD
Vendor: NanoHTTPD
Versions: All versions up to 2.3.1

Exploitation Mechanism

Attackers can exploit this vulnerability by passing malicious scripts through the query string, which are then executed by the GeneralHandler GET handler.

Mitigation and Prevention

It is crucial to take immediate steps to mitigate the risks posed by CVE-2020-13697.

Immediate Steps to Take

Update NanoHTTPD to a patched version that addresses the XSS vulnerability.
Implement input validation and output encoding to prevent XSS attacks.

Long-Term Security Practices

Regularly monitor and audit web server configurations for vulnerabilities.
Educate developers on secure coding practices to prevent similar issues in the future.

Patching and Updates

Stay informed about security advisories and promptly apply patches released by NanoHTTPD to address vulnerabilities.