  Cloud-based documents are inherently valuable, due to the volume and nature
of sensitive personal and business content stored in them. Despite the
importance of such documents to Internet users, there are still large gaps in
the understanding of what cybercriminals do when they illicitly get access to
them by for example compromising the account credentials they are associated
with. In this paper, we present a system able to monitor user activity on
Google spreadsheets. We populated 5 Google spreadsheets with fake bank account
details and fake funds transfer links. Each spreadsheet was configured to
report details of accesses and clicks on links back to us. To study how people
interact with these spreadsheets in case they are leaked, we posted unique
links pointing to the spreadsheets on a popular paste site. We then monitored
activity in the accounts for 72 days, and observed 165 accesses in total. We
were able to observe interesting modifications to these spreadsheets performed
by illicit accesses. For instance, we observed deletion of some fake bank
account information, in addition to insults and warnings that some visitors
entered in some of the spreadsheets. Our preliminary results show that our
system can be used to shed light on cybercriminal behavior with regards to
leaked online documents.
