Microsoft Security Bulletin MS03-047 828489

An attacker could seek to exploit this vulnerability by having a user run script on the attackers behalf. The script would execute in the security context of the user. If the script executes in the security context of the user, the attackers code could then execute by using the security settings of the OWA Web site (or of a Web site that is hosted on the same server as the OWA Web site) and could enable the attacker to access any data belonging to the site where the user has access.

To exploit this vulnerability through OWA, an attacker would have to send an e-mail message that has a specially-formed link to the user. The user would then have to click the link. To exploit this vulnerability in another way, an attacker would have to know the name of the users Exchange server and then entice the user to open a specially-formed link from another source while the user is logged on to OWA.

Note: Customers who have customized any of the ASP pages in the File Information section in this document should backup those files before applying this patch as they will be overwritten when the patch is applied. Any customizations would then need to be reapplied to the new ASP pages. Please refer to the Microsoft Support Policy for the Customization of Outlook Web Access available at http://support.microsoft.com/default.aspx?scid=kb;en-us;327178