Is it necessary to run a discovery scan for port 80 and 443 on your external ranges to identify new web applications or is there something done dynamically within the catalog to do this?
If you have regular VM scans on your external ranges, all you need to do is to click the 'update' button at the top of the catalog page. WAS will review all VM scans and update any newly identified HTTP/HTTPS services in those scans. This can take a while if you have a lot of scan data.
If you are not running regular scans, you can run a VM light inventory scan on your ranges, then when completed - click the update button on the WAS catalog page and you should see all HTTP/HTTPS services on all ports included in the scan.
You can alternatively also run a map scan and select and process a map - but this is less accurate as it only identifies open ports and not the actual service running. This is used when you just need a quick view on what is running on 80/443 and don't want to wait for full scans to be processed.
The Cataloging process, which uses your existing VM scanning data, only sees IP/Port combinations that have HTTP/HTTPs services running.
There is no way to automatically discovery applications. You would need to know where your applications are and put them into the WAS module via the many available options.
If you are looking for a way to discover applications your organization has built, but not catalogged, you might want to start by looking at DNS associated with your org or perhaps looking at All Ports open on your domains and interrogating those ports that have HTTP/HTTPS open. Then looking for unique apps within that list.
Retrieving data ...