Internet Explorer file:// Request Zone Bypass Vulnerability



Date Discovered

May 9, 2003


Internet Explorer is reported to be vulnerable to a zone bypass issue. Allegedly, if Internet Explorer attempts to open a web page containing numerous 'file://' requests each contained in a separate Iframe, the requested file will eventually be executed in the Local Computer zone.

Technologies Affected

  • Microsoft Internet Explorer 5.5
  • Microsoft Internet Explorer 5.5 SP1
  • Microsoft Internet Explorer 5.5 SP2
  • Microsoft Internet Explorer 6.0
  • Microsoft Internet Explorer 6.0 SP1


Run all software as a nonprivileged user with minimal access rights.
Always run Internet Explorer as an unprivileged user. This will limit the consequences of successful exploitation of this and other latent vulnerabilities.

Do not follow links provided by unknown or untrusted sources.
Exploitation of this vulnerability can be accomplished by following a link to a malicious website or by viewing maliciously crafted HTML email. Caution should be exercised in accepting any communications from unknown or untrusted users.

The vendor has released a cumulative patch to address this issue:



Discovery is credited to "Marek Bialoglowy" <>.

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