False positive for "Modern Web Application"

Describe the bug

I scan my website using Zaproxy.

I get the informational alert: “The application appears to be a modern web application. If you need to explore it automatically then the Ajax Spider may well be more effective than the standard one.” with:

Evidence: <a>

Problem: this was raised by a URL which corresponds to a JPEG image!

Indeed, if I look at the bytes in the image, I find the string “<a>”.

Steps to reproduce the behavior

Host an image containing bytes on a website.

Scan the website.

Observe the report.

Expected behavior

This should not raise the informational alert: “The application appears to be a modern web application”.

It makes no sense to deduce that from binary data.

I suggest that the alert should consider either the response body itself (it should be HTML) or the Content-Type header of the response.

Software versions

I use version 2.12.0

Screenshots

No response

Errors from the zap.log file

No response

Additional context

No response

Would you like to help fix this issue?

• Yes

[peter17]

@kingthorin Done, thanks!

[kingthorin]

@peter17 do you want to tackle fixing it?