Microsoft Internet Explorer 5.01 SP1 Security Update Web Credentials

From Microsoft:

This update resolves the "Cached Web Credentials" security vulnerability in Internet Explorer. Download now to prevent a malicious user from learning the credentials of another user and then using them to log onto a Web site as the other user. This vulnerability does not give a malicious user the ability to add, change, or delete files on your computer.

Under the "Cached Web Credentials" vulnerability, if a user logs onto a secured Web page using Basic Authentication, and subsequently visits a non-secure page on the same site, Internet Explorer automatically sends the cached credentials, normally a user ID and password, to the non-secure page. If a malicious user gains control over the other user's network communications, it is possible for the malicious user to read the credentials and use them. This vulnerability does not provide a means by which the malicious user can force another user to log onto a secure page, and can only be used to reveal credentials that had been cached during the current Internet Explorer session.