Web browser cookies used in Microsoft Entra authentication
During authentication against Microsoft Entra ID through a web browser, multiple cookies are involved in the process. Some of the cookies are common on all requests. Other cookies are used for specific authentication flows or specific client-side conditions.
Persistent session tokens are stored as persistent cookies on the web browser's cookie jar. Non-persistent session tokens are stored as session cookies on the web browser, and are destroyed when the browser session is closed.
|ESTSAUTH||Common||Contains user's session information to facilitate SSO. Transient.|
|ESTSAUTHPERSISTENT||Common||Contains user's session information to facilitate SSO. Persistent.|
|SignInStateCookie||Common||Contains list of services accessed to facilitate sign-out. No user information. Security feature.|
|CCState||Common||Contains session information state to be used between Microsoft Entra ID and the Microsoft Entra Backup Authentication Service.|
|build||Common||Tracks browser related information. Used for service telemetry and protection mechanisms.|
|fpc||Common||Tracks browser related information. Used for tracking requests and throttling.|
|esctx||Common||Session context cookie information. For CSRF protection. Binds a request to a specific browser instance so the request can't be replayed outside the browser. No user information.|
|ch||Common||ProofOfPossessionCookie. Stores the Proof of Possession cookie hash to the user agent.|
|ESTSSC||Common||Legacy cookie containing session count information no longer used.|
|ESTSSSOTILES||Common||Tracks session sign-out. When present and not expired, with value "ESTSSSOTILES=1", it will interrupt SSO, for specific SSO authentication model, and will present tiles for user account selection.|
|AADSSOTILES||Common||Tracks session sign-out. Similar to ESTSSSOTILES but for other specific SSO authentication model.|
|ESTSUSERLIST||Common||Tracks Browser SSO user's list.|
|SSOCOOKIEPULLED||Common||Prevents looping on specific scenarios. No user information.|
|cltm||Common||For telemetry purposes. Tracks AppVersion, ClientFlight and Network type.|
|x-ms-gateway-slice||Common||Microsoft Entra Gateway cookie used for tracking and load balance purposes.|
|stsservicecookie||Common||Microsoft Entra Gateway cookie also used for tracking purposes.|
|x-ms-refreshtokencredential||Specific||Available when Primary Refresh Token (PRT) is in use.|
|estsStateTransient||Specific||Applicable to new session information model only. Transient.|
|estsStatePersistent||Specific||Same as estsStateTransient, but persistent.|
|ESTSNCLOGIN||Specific||National Cloud Login related Cookie.|
|UsGovTraffic||Specific||US Gov Cloud Traffic Cookie.|
|ESTSWCTXFLOWTOKEN||Specific||Saves flowToken information when redirecting to ADFS.|
|CcsNtv||Specific||To control when Microsoft Entra Gateway will send requests to Microsoft Entra Backup Authentication Service. Native flows.|
|CcsWeb||Specific||To control when Microsoft Entra Gateway will send requests to Microsoft Entra Backup Authentication Service. Web flows.|
|Ccs*||Specific||Cookies with prefix Ccs*, have the same purpose as the ones without prefix, but only apply when Microsoft Entra Backup Authentication Service is in use.|
|threxp||Specific||Used for throttling control.|
|rrc||Specific||Cookie used to identify a recent B2B invitation redemption.|
|debug||Specific||Cookie used to track if user's browser session is enabled for DebugMode.|
|MSFPC||Specific||This cookie is not specific to any ESTS flow, but is sometimes present. It applies to all Microsoft Sites (when accepted by users). Identifies unique web browsers visiting Microsoft sites. It's used for advertising, site analytics, and other operational purposes.|
Cookie definitions and respective names are subject to change at any moment in time according to Microsoft Entra service requirements.
To learn more about self-service password reset concepts, see How Microsoft Entra self-service password reset works.
To learn more about multifactor authentication concepts, see How Microsoft Entra multifactor authentication works.