Shellshock Bash vulnerability could be exploited to hack Voice over IP systems worldwide. Attackers could exploit the flaw to change the configuration of the VoIP systems, to add and remove new users and hardware to the system, or to serve a malware to the SIP server and gain access to a company network. In a 12-hour period, its systems recorded 725 attacks, originated from 400 unique IP addresses mainly located in US and China, per hour against a total of 1,800 domains. Security researchers reported that bad actors were trying to exploit Bash Bug flaw worldwide.”]
Source: http://securityaffairs.co/wordpress/28704/hacking/shellshock-against-voip.html