Description
Due to a lack of verification of credentials when calls are being placed it is possible to cause calls on the MCS 5100 to either be placed as if they originate from a given user when they are not, or that they are placed to a given user when they are not.
Recommendations
To completely address the issue requires a patch from Nortel.More details can be found in Nortel SECURITY ADVISORY BULLETIN, 2008009102, Rev 1 at http://support.nortel.com/go/main.jsp?cscat=BLTNDETAIL&id=775223 Implementation of general best practice guidance will aid in limiting the exposure of this vulnerability. Nortel is recommending not to use snoop command to defend against potential exploits. In the short term it is recommended that a VoIP aware IPS product, such as VoIPguard, with signatures to detect attempts to exploit this issue, be implemented to prevent it from being exploited. Nortel customers with a valid support agreement may wish to speak with their support contact in order to obtain additional vendor details.