Vulnerability Note VU#830214

Nortel Networks Contivity VPN Client information leakage vulnerability

Overview

The Nortel Networks Contivity VPN Client authentication error message provide additional information that may be useful to an attacker.

I. Description

The Nortel Networks Contivity VPN Client software provides an encrypted and authenticated VPN connection from a client system to a Nortel Contivity VPN switch or gateway. The method that the software uses for reporting error messages may leak information that would be of use to an attacker. If a valid user name and an invalid password are given, the Contivity VPN Client displays "Login Failure due to: authentication failure". However, if an invalid user name is given, the Contivity VPN Client displays "Login Failed: Please verify the entered login information is correct". As a result, an attacker with the ability to observe the authentication error messages may be able to determine valid usernames on the corresponding server system. This information could further enable brute force or dictionary-based password guessing attacks.

II. Impact

An attacker with the ability to observe the authentication error messages would be able to determine valid user names in the system.

III. Solution

Upgrade the affected software

Nortel Networks has published an updated version of the Contivity VPN client software to address this issue. Please see the Systems Affected section of this document for more information.

Systems Affected

Vendor	Status	Date Notified	Date Updated
Nortel Networks	Vulnerable	8-Nov-2004

References

http://www.nii.co.in/vuln/contivity.html

Credit

Thanks to K. K. Mookhey of Network Intelligence India for reporting this vulnerability.

This document was written by Chad R Dougherty based on information provided by Nortel Networks.

Other Information

Date Public:	2004-10-18
Date First Published:	2004-11-08
Date Last Updated:	2004-11-08
CERT Advisory:
CVE-ID(s):
NVD-ID(s):
US-CERT Technical Alerts:
Metric:	0.65
Document Revision:	9

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

Get Adobe Reader