Vulnerability Note VU#251788
Microsoft Internet Explorer does not safely handle multiple file download requests
A problem in the way Microsoft Internet Explorer handles a large number of file download requests could result in the execution of arbitrary code on a vulnerable system.
When Internet Explorer (IE) follows a link to an executable file (.exe), a dialog window is displayed that prompts the user to open the file, save the file, or cancel the operation. When handling a sufficiently large number of file download requests, IE eventually fails to display the dialog window and executes the specified file without user intervention. A dialog is displayed for each download request, and it may be possible to terminate the IE process before the file is executed. Publicly available examples use large numbers of frames (FRAME or IFRAME elements) to generate download requests.
Other software that uses the WebBrowser ActiveX control may be affected.
An attacker who is able to convince a user to access a specially crafted HTML document, such as an Internet web page or HTML email message, could execute arbitrary code with the privileges of the user. Resource exhaustion caused by the large number of download requests could also cause a denial of service.
Configure Outlook and Outlook Express to open email messages in the Restricted Sites Zone, where file downloads are disabled by default. This change can be made manually or as part of the Outlook Email Security Update for Outlook 98 and Outlook 2000. Outlook 2002 and Outlook Express 6 use the Restricted Sites Zone and by default.
Note that a different vulnerability could allow the file download restriction in Outlook and Outlook Express to be bypassed. If file downloads are disabled in the zone used by Outlook and Outlook Express but enabled in the zone containing the attacker's executable file, a specially crafted email message could generate enough download requests to execute the attacker's file. It is important to disable file downloads in both the zone used by Outlook and Outlook Express and the zone(s) used by IE to browse untrusted sites.
Systems Affected (Learn More)
|Vendor||Status||Date Notified||Date Updated|
|Microsoft Corporation||Affected||12 May 2003||04 Jun 2003|
CVSS Metrics (Learn More)
This vulnerability was publicly reported by Marek Bialoglowy.
This document was written by Art Manion.
- CVE IDs: CVE-2003-0309
- Date Public: 08 May 2003
- Date First Published: 16 May 2003
- Date Last Updated: 08 Dec 2006
- Severity Metric: 51.84
- Document Revision: 30
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