The subject matter of this specification can be implemented in, among other things, a method that includes storing, in a collaboration platform, a first geographic location and a first time of a first authentication request for an account at the collaboration platform responsive to successful authentication of the first authentication request. The method includes receiving a second authentication request for the account at the collaboration platform. The method includes identifying a second geographic location and a second time of the second authentication request. The method includes providing access to the account responsive to a determination that a difference in time between the first time and the second time is large enough that a user of the account is able to travel a difference in distance between the first geographic location and the second geographic location within the difference in time.