Government and large corporations are at high risk of their IP telephones being hacked. These entities have a large number of IP phones which an employee can hack or an outsider could trick an employee into clicking on an e-mail attachment that contains a virus, infect the employee's computer and then use that same computer to attach IP phones inside the company's network.
Also, a phone technician or someone posing as one, can hack these IP phones because that person would have access to the phones.
Here is the device that can be used to hack a Cisco IP phone
All you have to do is to plug the device into the IP phone port. The phone will need internet access.
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