Slican telephone exchanges use symmetric encryption for TCP/IP communication. Secret key is hardcoded in multiple binary files. An attacker who has access to these files can decrypt the communication. This issue was fixed in IPx series version 6.62.0100. The issue STILL EXISTS in End-Of-Life telephone exchanges: - CCT-1668 (CCT1CPU) - MAC-6400 - CXS-0424 These products were discontinued in 2011 and 2012 and and will not receive updates. These products require a hardware update in order to receive a software update. The vendor recommends that users of these devices contact the their service department directly to determine the options for upgrading.