In cases where suspicious activity has been detected on an account, a login challenge may be issued in order to determine that the user in question is human (and not a bot, for example), or is who they claim to be.
See also: Bot / Bot Account, IP Address, CAPTCHA
Commentary:
- Login challenges may occur, for example, when a user logs in to a service from a previously unknown device, or from an IP address in a geographic location that differs from their usual account activity.
- A login challenge could consist of a CAPTCHA, requiring the user to confirm non-public data linked to their account (such as a phone number) through confirmation with a separate device, or by uploading official documents.