[原文]Nortel Contivity VPN Client V05_01.030, when configuring a certificate to be used as authentication, does not properly drop system privileges, which allows local users to gain privileges by opening a program with the File Open dialog box.
Nortel VPN Client Software Local Privilege Escalation
Local Access Required
Loss of Integrity
Nortel VPN Client contains a flaw that may allow a malicious user to gain access to unauthorized privileges. The issue is triggered when the client is manipulated to run local commands. The VPN Client allows the local user to select an application instead of a configuration file or replace a VPN Client application with a local application. The following application screens can be manipulated (e.g. Change file to cmd.exe) to allow this flaw to occur:
- Options >> Authentication Options >> Digital Certificate Authentication Entrust
- Connection Wizard
- Group Authentication Options >> Challenge Response Token Options >> Software Token Directory
This flaw may lead to a loss of integrity as any local commands can be executed as the same user as the VPN Client (typically running as a service under the Window System account).
Currently, there are no known upgrades or patches to correct this issue. It is possible to correct the flaw by implementing the following workaround:
Run the client as a local user application and not as a service