Article ID: 968943 - View products that this article applies to.
Public IM Connectivity (PIC) users can send spam over IM to a Communicator Web Access (CWA) user even if PIC users are not in the CWA user's contacts list.
Communicator Web Access does not block PIC users who are not in the contacts list.
To resolve this problem, apply the following update:
967674This update blocks PIC users from sending spam over IM by adding public IM users to a blocked container. CWA users can explicitly add a PIC user to a non-blocked container category so that they can receive instant messages from specific PIC users with whom they want to communicate.
(http://support.microsoft.com/kb/967674/ )Description of the update package for Communications Server 2007 R2, Unified Communications Manager API 2.0 Core Redist 64-bit: April 2009
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.