Your Phone Number is More Vulnerable Than You Think: A Deep Dive into SS7

This article is essential for the general public, especially those regularly sharing their phone numbers online, as well as privacy-conscious individuals, activists, and journalists. It demystifies SS7 vulnerabilities and underscores the risks of indiscriminate phone number sharing, offering practical tips for enhancing digital security and online privacy.

After viewing an episode of "Mr. Robot"(TV show) that features the elusive Deus Group (the top 1% of the 1%), one may find themselves intrigued by the group's practice of changing phone numbers every five days. At first glance, this approach appears excessive. Why not simply use basic or encrypted phones? A deeper understanding of this strategy comes to light upon exploring SS7 attack vectors, especially for those studying cybersecurity. Possessing just a phone number enables someone to be located, tracked, and manipulated due to the SS7 (Signalling System 7) vulnerability, a lingering and notorious flaw in telecommunications.

What is SS7 and Why Should We Care?

SS7 serves as the backbone for most of the world's cellular networks. It is the system responsible for directing calls and messages to their intended destinations. However, it was designed in an era when security was not a prime concern, leaving it susceptible to various attacks. Technically, it is a protocol suite used for signaling in Public Switched Telephone Networks (PSTNs) and cellular networks. It was developed in the 1970s for handling tasks like call setup, routing, and teardown, as well as other services like SMS and number translation.

How do SS7 Attacks work? In a typical SS7 attack, a malicious actor uses a series of SS7 signaling requests to trick the mobile operator into redirecting text messages and calls to an attacker-controlled endpoint. They can intercept your two-factor authentication (2FA) codes or even eavesdrop on your calls. Imagine someone rerouting your home's mail to their address; it is similar but far more dangerous.


The Challenge of Fixing SS7 is that its architecture was designed when security was not a primary concern, and international telecom networks trusted each other implicitly. The global scale and legacy nature of SS7 makes security upgrades complex, expensive, and time-consuming. Like trying to replace the foundation of a skyscraper without tearing it down—it is complicated and very, very costly.

Who Can Exploit This? (Accessibility of these Attack Tools)

Kali Linux, an operating system similar to Windows or Mac but designed for cybersecurity tasks, houses a range of free and open-source tools that are perfect recipes for exploiting SS7 vulnerabilities. One does not need to be a government agency or a well-funded criminal organization to exploit these vulnerabilities; with moderate computer skills and the right tutorials, anyone can become a potential attacker.

Spotlight on SigPloit: Take SigPloit, for example. This tool provides a framework for exploiting telecom vulnerabilities and has a user-friendly interface. Simply put, SigPloit is like a Swiss Army knife for anyone interested in telecom hacking. It offers different modules that can perform various attacks, including tracking a phone's location or intercepting messages.

How Easy Is It? Downloading and installing Kali Linux and SigPloit are straightforward processes, with numerous guides and community forums available to help with any bumps. Once set up, executing an SS7 attack could be as simple as running a few commands. The ease of use is what makes it particularly unsettling; a teenager in their basement could, theoretically, tap into this powerful and invasive technology.

Real-world Impact: From Convenience to Catastrophe

Emergency Services Like 911: It is worth mentioning that SS7 is okay; it is crucial for the functioning of services we rely on daily. For example, when you call emergency services like 911, SS7 helps pinpoint your location to send assistance quickly. While this is beneficial, the same feature can be exploited for nefarious purposes.

Financial Fraud in Germany: One of the most alarming instances occurred in Germany in 2017. Criminals exploited SS7 vulnerabilities to bypass two-factor authentication (2FA) protections on bank accounts. They intercepted SMS-based authentication codes and successfully drained several bank accounts.

Targeting Activists: The system has also been weaponized against activists and dissidents. In 2016, an SS7 attack was suspected to have been used by the Turkish government to track the movements of a group of activists, leading to their arrest.

Journalists and Whistleblowers: Journalists and whistleblowers are another group often targeted via SS7 vulnerabilities. By tapping into their phone communications, oppressive regimes can identify sources and leak sensitive information.

The Ubiquity of the Risk: What is troubling is that these are not isolated incidents or theoretical possibilities. The ease of accessing SS7 attack tools makes it a pervasive risk, affecting everyone from the average citizen to high-profile individuals.

Hence, it is advisable to exercise caution before disseminating one's phone number or using it for online promotions. The recommendation is to utilize virtual numbers for online registrations, rotating these alternate numbers at regular intervals. Awareness and simple precautionary measures can significantly contribute to enhancing digital security.