A web server running a ASP.NET web service. To use the web service you must go to http://example.com/UtilServerComp/getCashNow7899.asmx
Adding ?WSDL is possible to get service description.
I assume that without knowledge of the URL and exact name of the .asmx this page will not be found or am I wrong? Crawling the web site will not work since you have to guess the name getCashNow7899 as well as UtilServerComp and that is not very likely...
It is rather unlikely that someone will find out your service without knowing the name. Also remember that you can switch off the documentation protocol:
<webServices>
<protocols>
<remove name="Documentation"/>
</protocols>
</webServices>
However, if you deploy any application that uses the service, the client could use an http debugger to sniff the traffic and learn the exact address and the exposed interface.