Version detection

Once we've confirmed that the server is running Tomcat, the next step is to establish the version information. In this section, we will look at a number of ways of detecting the version number of existing Tomcat installations.

Version detection via the HTTP 404 error page

By default, Tomcat's 404 error page discloses the version number that it is running, so all we need to do is to visit a URL that does not exist on the server and the server should throw back an error page, as in the following screenshot:

Many administrators don't really hide the web server banner that discloses the version number. A threat actor can use this information to find a public or zero-day exploit from their arsenal...