Privilege escalation in Nortel Contivity VPN Client V05_01.030

[Jeff Peadro <jeff.peadro () gmail com>]

Summary:
Privilege escalation in Nortel Contivity VPN Client V05_01.030
(http://www.nortel.com)

Details:
The Contivity VPN Client is a Windows application that lets you define
and store connection information for accessing your corporate network
through a Contivity Secure IP Services Gateway.  When the Contivity
client is running as a service it is possible to manipulate the
interface of the client and escalate privileges to that of the
LocalSystem account.

Vulnerable Versions:
Nortel Contivity VPN Client V05_01.030

Patches/Workarounds:
The vendor was notified of the issue and an updated version has been released.

Exploit:

1. With the Contivity client open click on Options and select
Authentication Options.

2. Select Digital Certificate Authentication Entrust and click OK.

3. To the right of the certificate box click the button icon and select open.

4. Change Files of type: to All Files, navigate to the system32
directory and    locate cmd.exe. Right click cmd.exe and choose Open.

It should also be noted that this exploit can be carried out by
running the connection wizard and following steps 2-4.

The result is a command prompt running under the context of the
LocalSystem account.

Discovered by Jeff Peadro Jeff.Peadro[at]gmail[dot]com
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