[NT] Nortel Contivity VPN Client Privilege Escalation

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  Nortel Contivity VPN Client Privilege Escalation
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SUMMARY

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.

DETAILS

Vulnerable Systems:
 * Nortel Contivity VPN Client version 05_01.030

By using the  Digital Certificate Authentication Entrust  attackers may 
receive console with the permission of LocalSystem account that will 
result in a privileges escalation, and will allow attackers to execute 
arbitrary programs, with that  LocalSystem privilege.

Proof of Concept:
  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.

Vendor Status:
The vendor was notified of the issue and an updated version has been 
released.


ADDITIONAL INFORMATION

The information has been provided by  <mailto:[email protected]> Jeff 
Peadro.



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