Microsoft Warns of Bug in IE
- By Scott Bekker
- February 18, 2000
Microsoft has released a patch that eliminates a security vulnerability in Internet Explorer (IE). The vulnerability could allow a malicious user to read, but not add, change, or delete, certain types of files on the computer of a visiting user.
When a Web server navigates a window from one domain into another, the IE security model checks the server's permissions on the new page. It is possible, however, for a Web server to open a browser window to a client-local file, then navigate the window to a page that is in the Web site's domain in such a way that the data in the client-local file is accessible to the new window. The data would only be accessible to the new window for a very brief period, but the result is that it could be possible for a malicious Web site operator to view files on the computer of a visiting user. The operator would need to know or guess the name and location of the file, and could only view file types that can be opened in a browser window.
IE 4.0, 4.01, 5, and 5.01 are all affected by the vulnerability. Patches are available at http://www.windowsupdate.microsoft.com and http://www.microsoft.com/windows/ie/security/patch5.asp. -- Isaac Slepner
Scott Bekker is editor in chief of Redmond Channel Partner magazine.