Microsoft Exchange 2000 allows remote authenticated attackers to cause a denial of service via a large number of rapid requests, which consumes all of the licenses that are granted to Exchange by IIS.

An interaction between Microsoft Outlook Web Access (OWA) with RSA SecurID allows local users to bypass the SecurID authentication for a previous user via several submissions of an OWA Authentication request with the proper OWA password for the previous user, which is eventually accepted by OWA.

Cross-site scripting (XSS) vulnerability in Microsoft Exchange Server 2000 SP1 through SP3, when running Outlook Web Access (OWA), allows user-assisted remote attackers to inject arbitrary HTML or web script via unknown vectors related to "HTML parsing."