The problem started a day after installation as completed.The destinations being dialed automatically are unknown to us and are not even in address book or dial list.
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Polycom Global Services
There are a series of web bots trying to exploit devices open to the internet or SIP trunks. Google SIPVicious & Metasplot for detais of SIP & H.323 culprits. Other than network Firewall security measures, what is recommended is to place the HDX in Do Not Disturb mode & ensure Availability Control is on in the Home Screen. This will prevent unwanted INBOUND calls. I can't imagine how the HDX could make random outbound calls unless the Web UI was open. The HDX Security will allow you to place a strong pw on the Admin Web UI & Whitelist users who are allowed to access it.