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CERT Coordination Center

Macromedia JRun ISAPI DLL filter vulnerable to buffer overflow via request for long Host header field

Vulnerability Note VU#703835

Original Release Date: 2002-05-29 | Last Revised: 2003-04-09


A remotely exploitable buffer overflow exists in Macromedia's JRun version 3.1 on Win32 platforms.


A remotely exploitable buffer overflow exists in the Win32 version of Macromedia's JRun version 3.1 on Win32 platforms.

JRun is an application server that works with most popular web servers such as Apache and IIS. Macromedia states that JRun is deployed at over 10,000 organizations worldwide.

As reported in the Next Generation Security Software Advisory (#NISR29052002), a remotely exploitable buffer overflow exists in the ISAPI filter/application. Specifically, the buffer overflow exists in the portion of code that handles the host header field. If an attacker sends a specially crafted request to the application server, he can overwrite a return address on the stack. Because the vulnerable DLL is running in the address space of the web server process (at least on IIS 4 & 5), code submitted by the attacker will be run with SYSTEM privileges.


A remote attacker can execute arbitrary code on the vulnerable target with SYSTEM privileges.


Apply the patch from Macromedia Inc. or upgrade to JRun 4.


Vendor Information


Macromedia Inc. Affected

Notified:  May 29, 2002 Updated: May 29, 2002



Vendor Statement

Macromedia has confirmed that this is a problem in older versions of JRun 3.0 and 3.1 and is soon to publish a security bulletin regarding this.  Visit the Macromedia security zone site at for more information.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

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This vulnerability was discovered by David Litchfield of Next Generation Security Software.

This document was written by Ian A. Finlay.

Other Information

CVE IDs: CVE-2002-0801
Severity Metric: 54.00
Date Public: 2002-05-29
Date First Published: 2002-05-29
Date Last Updated: 2003-04-09 18:50 UTC
Document Revision: 53

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