SonicWall NetExtender NELaunchCtrl ActiveX control stack buffer overflow

Overview

The SonicWall NetExtender NELaunchCtrl ActiveX control contains a stack buffer overflow, which could allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

Description

SonicWall NetExtender is an SSL VPN client that is implemented by using an ActiveX control. The NELaunchCtrl ActiveX control, which is provided by NELaunchX.dll, contains a stack buffer overflow in the AddRouteEntry() method.

Exploit code for this vulnerability is publicly available.

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Impact

By convincing a user to view a specially crafted HTML document (e.g., a web page or an HTML email message or attachment), a remote, unauthenticated attacker may be able to execute arbitrary code with the privileges of the user on a vulnerable system.

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Solution

Apply an update
This vulnerability is addressed in the client software provided by the 2.5 firmware for the SonicWall NetExtender 4000 and 2000 series VPN units. This update provides version 2.5.0.53 of the NELaunchCtrl ActiveX control. The vulnerability is also addressed by the 2.1 Patch Build for the SonicWall NetExtender 200 series VPN units. This update provides version 2.1.0.51 of the NELaunchCtrl ActiveX control. These updates can be obtained from the SonicWall Support page. Please note that the client systems must connect to a NetExtender SSL VPN unit to obtain the fixed control. If you are unable to obtain a fixed version of the control, please consider the following workarounds:

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Disable the NELaunchCtrl ActiveX control in Internet Explorer

The vulnerable ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSID:

{6EEFD7B1-B26C-440D-B55A-1EC677189F30}
More information about how to set the kill bit is available in Microsoft Support Document 240797. Alternatively, the following text can be saved as a .REG file and imported to set the kill bit for this control:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\``{6EEFD7B1-B26C-440D-B55A-1EC677189F30}``]
"Compatibility Flags"=dword:00000400
Disable ActiveX

Disabling ActiveX controls in the Internet Zone (or any zone used by an attacker) appears to prevent exploitation of this and other ActiveX vulnerabilities. Instructions for disabling ActiveX in the Internet Zone can be found in the “Securing Your Web Browser” document.

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Vendor Information

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SonicWall __ Affected

Notified: September 20, 2007 Updated: November 05, 2007

Status

Affected

Vendor Statement

`SSL-VPN 200 Platform

The fix was made publicly available on 7/20/07 with the web-post of
2.1.0.0-8sv. The web-posted firmware contains version 2.1.0.51 of the
NELaunchCtrl ActiveX control, which fixed the issue.

SSL-VPN 2000/4000 Platform

The fix was first made publicly available on 10/22/07 with the web-post
of 2.5.0.0-9sv. The web-posted firmware contains version 2.5.0.53 of
the NELaunchCtrl ActiveX control, which fixed the issue.`

Vendor Information

We are not aware of further vendor information regarding this vulnerability.

Addendum

These updates can be obtained from the SonicWall Support page. Please note that the client systems must connect to a NetExtender SSL VPN unit to obtain the fixed control. If you are unable to obtain a fixed version of the control, please disable the ActiveX control.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23298521 Feedback>).

CVSS Metrics

Group	Score	Vector
Base
Temporal
Environmental

References

• <http://www.sec-consult.com/fileadmin/Advisories/20071101-0_sonicwall_multiple.txt&gt;
• <http://www.sonicwall.com/us/643.htm&gt;
• <http://secunia.com/advisories/27469/&gt;

Acknowledgements

This vulnerability was reported by Will Dormann of the CERT/CC. It was also independently discovered by lofi42.

This document was written by Will Dormann.

Other Information

CVE IDs:	CVE-2007-5603
Severity Metric:	25.92 Date Public: