First up, the mildest of the three. Microsoft XML Core Services (MSXML) may ignore IE security zone settings during a request for data from a Web site, meaning that an attacker could request data from the user's local drive. It would be necessary for the attacker to know the path to the file being sought, and he would have only read privileges. HTML e-mail seems not to be vulnerable to this sort of attack. The hole exists in the XMLHTTP ActiveX control, which "allows Web pages to send and receive XML data via HTTP operations such as POST, GET, and PUT." Supposedly there are security mechanisms to prevent abuse, but they're obviously not quite comprehensive.
This affects XML versions 2.6, 3.0, and 4.0, and means that SQL Server 2K, Win-XP and IE6 are vulnerable. The patch is available via Windows Update. Further details may be found in the MS bulletin.
Next, we have a defective ISAPI filter in Commerce Server 2000 which can lead to a root compromise. The so-called AuthFilter, which suports several types of authentication, contains an unchecked buffer. Those who have deployed the URLScan tool successfully will not be vulnerable to root compromise, but are still vulnerable to DoS attacks. The vulnerability does not affect IIS; it exists in an added 'feature' in Commerce Server only.
Finally, and worst of all, we have a little problem with VBscript in Internet Explorer 5.01, 5.5, and 6.0 which could allow an attacker to read files on a victim's local drive, or eavesdrop on his browsing session. The defect essentially allows scripts in one domain to access the contents of another domain in a frame, the MS bulletin explains.
This could enable an attacker to glean personal information like login names and passwords, and credit card details.
It's also possible for an attacker to exploit this hole with HTML e-mail. Since MS won't let you switch off HTML rendering in Outlook and Outlook Express (the spam lobby won't allow it), you'll just have to activate Windows Update and fix your browser, which will in turn fix your e-mail client.
Those using IE 5.01 SP2 can only get relief with Win-2K service packs and security roll-up packages. Those with IE versons earlier than 5.01 SP2 are completely out of luck. You'll have to upgrade.
How about to Linux? ®