We have a situation in which a sensitive website is blocked from being crawled using a robots.txt file. This works well, however the problem is that for a period of time the team used semantic urls in which /sensitive-stuff-are-leaked-through-the-very-url.
Links to these pages were sent via email and some recipients had antiviruses that automatically uploaded a link to the scanned web page on some public database (the many website checkers that can be found online to test if a URL is safe).
Now the problem is that when certain search terms are used, even though the website itself does not appear in Google Search results, these antivirus scan result pages containing the scanned link show up. The pages have been deleted and we've ramped up our security / privacy practices since then. But these search results remain nevertheless a HUGE problem. The semantics of the URLs leak project names and customer names among other things.
So this is quite a huge problem to have this show up when the name of our client's company is searched. 90% of these antivirus website owners have been cooperative but a couple of others haven't, and this is a problem.
Would a noindex meta tag help in this situation? I am not sure if this would prevent third party pages mentioning the link from appearing in search results, since these third-party pages would be legitimately indexed.