Multiple Vulnerabilities in Microsoft Internet Explorer 5.5 and 6.0

Reported December 13, 2001, by Microsoft.



·         Microsoft Internet Explorer 6.0

·         Microsoft Internet Explorer 5.5


Three new vulnerabilities exist in Microsoft Internet Explorer (IE) 6.0 and 5.5. The first vulnerability results from a problem in the way that IE handles the Content-Type and Content-Disposition header fields in an HTML stream. By modifying these fields in a specific way, an attacker can fool IE into thinking that the file is a different file type and can open harmful files. To work around this problem, users must disable file downloads completely under the appropriate IE security zones. The second problem involves a variant of the Frame Domain Verification vulnerability that lets a malicious intruder use a Web site to read any file on the local computer. The third vulnerability involves a problem with the filenames that IE displays in the File Download dialog box. In an attempt to trick the user, an attacker can use this vulnerability to misrepresent the name of the file presented for download.



The vendor, Microsoft, has released Security Bulletin MS01-058 to address these vulnerabilities and recommends that affected users apply the patch provided at this URL. This patch is cumulative roll-up of all patches the company has previously issued for these versions of IE. Microsoft no longer supports previous versions of IE.


Discovered by Jouko Pynnonen, Juan Carlos G. Cuartango, and Jesús López de Aguileta.

TAGS: Security
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