Potential fix for code scanning alert no. 34: Cross-site scripting

[davewichers]

Potential fix for https://github.com/aspectsecurity/TestCodeQL/security/code-scanning/34

In general, to fix XSS issues in servlet code, user-supplied data must be contextually encoded or escaped before being written into HTML, attributes, JavaScript, or other browser-interpreted contexts. For text written into the HTML body, HTML encoding (escaping characters like <, >, &, ", ') is appropriate.

For this specific code, the minimal fix that preserves existing behavior while preventing XSS is to HTML-encode bar before printing it. We should not change how bar is computed, only how it is rendered. The best approach, consistent with the constraint to only add well-known imports, is to use Apache Commons Text’s StringEscapeUtils.escapeHtml4. However, since we cannot assume that dependency already exists and we should avoid adding new dependencies when not necessary, a safer choice within the snippet is to implement a very small, local HTML-escaping helper method in this class and use it at the sink.

Concretely:

• Add a private static helper method escapeHtml(String input) inside Benchmark00728 that replaces at least &, <, >, ", and ' with their HTML entities.
• Change line 56 from response.getWriter().println(bar); to response.getWriter().println(escapeHtml(bar));.
• No additional imports are required.

All changes occur within src/main/java/org/owasp/benchmark/testcode/Benchmark00728.java, by inserting the helper method inside the class and updating the print call.

---

Suggested fixes powered by Copilot Autofix. Review carefully before merging.