Conference:  Defcon 31

Authors: Tracy Mosley Trenchant

2023-08-01

4G? LTE? 3GPP? A lot of telecommunications terminology gets thrown around, but what does it actually mean? While terms like “5G”, and “packet core” may be in common use, it’s hard to understand what they mean in terms of attack surface, or even as a consumer. Very often even network diagrams will show “Core Network” as a big blob, or stop at the Radio Access Network. It’s hard to have insight into the cellular network. So, I’ll explain generation by generation! In this talk we will walk through each step of cellular evolution, starting at 2G and ending at 5G. The never-ending attack and defend paradigm will be clearly laid out. In order to understand the attack surface, I’ll cover network topology and protocol. For each cellular generation, I will explain known vulnerabilities and some interesting attacks. In response to those vulnerabilities, mitigations for the subsequent cellular generation are put in place. But as we all know, new mitigations mean new opportunities for attackers to get creative. While I will explain most cellular-specific terminology, a familiarity with security concepts will help to better understand this talk. Basic foundations of communications systems, information theory or RF definitely make this talk more enjoyable, but are absolutely not necessary. It’s a dense topic that is highly applicable to those working on anything that touches the cellular network!