Overview#
Signalling System No. 7 (SS7) is a set of Telecommunications signaling protocols developed in 1975, which is used to set up and tear down most of the world's Public Switched Telephone Network (PSTN) telephone calls.Signalling System No. 7 is part of the common-channel signaling (CCS)
Signalling System No. 7 also performs number translation, Local number portability, prepaid billing, Short Message Service (SMS), and other mass market services.
Common Channel Signalling System 7 (CCSS7) is how Signalling System No. 7 is referred to in the United States and In the United Kingdom, it is called C7 (CCITT number 7),
What does Signalling System No. 7 do?#
Signalling System No. 7 is a set of protocols allowing phone networks to exchange the information needed for routing data between each other and to ensure correct billing.Signalling System No. 7 also allows users on one network to roam on another, such as when travelling in a foreign country.
Signalling System No. 7 Vulnerability#
Edward Snowden’s 2013 document dump revealed that the National Security Agency was using Signalling System No. 7 for Surveillance on individuals.There have been several SS7 hacks.
