Description
Due to the manner in which sessions and authentication are managed it is possible to cause Microsoft Communicator to open a very large number of sessions resulting in the consumption of huge amounts of memory, potentially resulting in a Denial of Service.
Recommendations
Microsoft has acknowledged the issue and is working on correcting it . I n 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. Implementing best practices can limit the exposure of this issue. Microsoft customers with a valid support agreement may wish to speak with their support contact in order to obtain further vendor details.