I have a web app which emails me exceptions automatically. This morning there was an error relating to a url: /Catalog/LiveCatalog?id=ylwpfqzts
id is invalid (should be a guid) and caused an error parsing. Everything was handled correctly, and an error page is returned. But what was odd is that the user-agent reported itself as Googlebot and the IP is registered to Google.
The URL would never have been generated by my web app but doesn't look particularly malicious.