After a spate of spam started coming to the email accounts of Dropbox users, the company says it has brought in reinforcements to make sure the problem is not internal. In a forum post, Dropbox said "we continue to investigate and our security team is working hard on this. We’ve also brought in a team of outside experts to make sure we leave no stone unturned." This suggests that the problem might be related to Dropbox's own system, though the post also says that "we haven’t had any reports of unauthorized activity on Dropbox accounts."
The spam issue started yesterday, with some users reporting that they were receiving spam to addresses used for nothing but Dropbox. The company responded that it was "investigating" the issue, which could involve compromised third-party apps or something more serious. A short outage yesterday, however, had nothing to do with the problem, Dropbox says.