Regarding the HackerOne program you can have a look at the bottom of this page:
https://hackerone.com/dropbox
and have a look for bug-report titles. These are the reports that were publicly disclosed and valid reports (won't-fixes are not in that list).
Or you might go for a search for "dropbox" here (that comes in handy if there are a lot of reports):
http://h1.nobbd.de
Some information about the counterfeit bills can be found in a article by Brian Krebs that appeared last year.
Related Hacker News Thread:
https://news.ycombinator.com/item?id=8203885
I just realized the search function wasn't working when I submitted this. I fixed it a minute ago and you should be able to search through all the issues now.
If you have any recommendations concerning layout improvements or readability feel free to let me know :-)