Webex, in some cases, automatically uses CAPTCHA to detect and block fraudulent attacks. You can enable CAPTCHA in Site Administration for the following:

• Attendees joining Personal Room Meetings.

• During account sign-up for your managed sites that don’t have single sign-on enabled.

When Webex automatically uses CAPTCHA or when it is enabled by the site administrator, attendees are prompted to enter the CAPTCHA text while joining a meeting. Attendees will be unable to join a meeting without successfully entering the CAPTCHA text.

CAPTCHA is triggered in the following instances:

• If an attendee exceeds the threshold for the allowed number of incorrect meeting password attempts, then the attendee is prompted to enter the CAPTCHA text.

• If a user exceeds the threshold for the allowed number of incorrect meeting number attempts, then the user is prompted to enter the CAPTCHA text.

• If a user exceeds the threshold for the allowed number of incorrect Personal Meeting Room Vanity ID attempts, then the attendee is prompted to enter the CAPTCHA text.

• When a user selects "Notify Host" when the Site Administration feature "Allow attendees to notify the host that they are waiting in the Personal Room/ Webex Meeting lobby" is enabled.

  Attendees who have not signed in (whose identity is unauthenticated), or who have signed in, but belong to an external organization, are prompted to enter the CAPTCHA text.

• When the site administrator has checked the box Show CAPTCHA when attendees enter a host's Personal Room, then an attendee who has not signed in (whose identity is unauthenticated) is prompted to enter the CAPTCHA text

• When the site administrator has enabled the Show security check in the signup form option for account sign up, then the user is prompted to enter the CAPTCHA text.