SS7, also known as Common Channel Signaling System No. 7, is a protocol system used by communication networks to exchange information about routing and billing between different telephone networks.

History of SS7

The SS7 protocol was developed in the 1970s as a way for different telephone networks to communicate with each other. It was the primary method used to route and bill calls between various phone networks for years.

Despite its age, SS7 is still widely used today due to its reliability and efficiency. However, this also makes it a prime target for hackers who want to access the data transmitted over SS7 networks.

SS7 today

This foundational network infrastructure has served telecommunications networks for many years, but it is increasingly vulnerable to attacks from hackers who exploit flaws in its security protocols. By gaining access to SS7, attackers can intercept calls and text messages, redirect calls, steal money from bank accounts, and even deploy surveillance technologies.

Type of SS7 attacks

One of the most common forms of attack against SS7 is known as a replay attack. By obtaining an authentication code used by one call or message, hackers can use that code to re-send that same call or message to another number. This can be used to intercept calls and text messages and fraudulently rack up charges on someone's phone bill.

Another way that SS7 can be exploited is through a man-in-the-middle attack. In this type of attack, hackers insert themselves into the communication between two devices, either by setting up a fake cell tower or taking advantage of an existing one. Once in the middle of the communication, attackers can listen to calls and read texts and manipulate the messages being sent between two phones.

There have been several high-profile attacks against SS7 on cellular networks designed for 4G and 5G. As the world moves towards 5G, it is important to be aware of the increased risks posed by this outdated protocol system.

SS7 Attack mitigation

While there are some steps that telecom companies can take to mitigate the risks posed by SS7, the only real solution is to replace this aging infrastructure with a more secure system. Our calls and texts will remain vulnerable to interception and fraud until that happens.

What you can do

In the meantime, the best way to secure your text messages or voice calls is to use an end-to-end encrypted messaging app like Signal. This will ensure that your communication is protected from eavesdropping, even if the network itself is compromised.

Sources:

  • [www.wired.com/story/ss7...](https://www.wired.com/story/ss7-guide-what-is-it-how-does-it-work-and-why-is-it-dangerous/)

  • [www.zdnet.com/article/w...](https://www.zdnet.com/article/what-is-ss7-and-why-are-attackers-exploiting-it/)

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