Researchers at InTheCyber firm have discovered a new easy exploitable and dangerous vulnerability affecting messaging systems. When the mobile operator relies on caller-id to authenticate the user inside his voicemail, an attacker could falsify his caller ID in order to impersonate the user. At the moment, two of the biggest Italy mobile operators allow this kind of attack. This undoubtedly raises problems about the privacy of the communications, especially the information stored inside the voicemail. This old flaw could be weaponized in. order to compromise other services.”]
Source: http://securityaffairs.co/wordpress/52619/hacking/hacking-messaging-systems.html