We've received some questions regarding a reported cross-site scripting (XSS) issue affecting Internet Explorer.  Google Desktop was used in a proof of concept to demonstrate how, in some cases, this issue could allow an attacker to obtain sensitive information.  This issue may be a bit confusing because it is not really an XSS issue.  A better way to describe it might be to call it “cross-site information disclosure”. Our investigation indicates that this issue will have limited impact because an effective attack requires a website to expose sensitive information in a specific way.  Basically, an attacker would need to find a way to make a response look like a Cascading Style Sheet, and that response would need to contain sensitive information.

Google has done a good thing for the protection of our mutual customers by mitigating the issue on their servers.  We think that is great.  The underlying cross-site issue still exists within IE and I want to reassure you that we are investigating the root cause of this issue.  Once the investigation is complete we'll take appropriate action for our customers which may include fixing this in a future security update for IE.

-Mike

*This posting is provided "AS IS" with no warranties, and confers no rights.*