Iranian Society of Cryptology The ISC International Journal of Information Security 2008-2045 Articles in Press 2026 02 12 5G Attacks: Realistic Scenarios and Simulations Using Open5GS 240534 10.22042/isecure.2026.240534 EN Mahdi Jeyhoon Department of Electrical Engineering, SR.C., Islamic Azad University, Tehran, Iran. Maryam Rajabzadeh Assar Department of Electrical Engineering, SR.C., Islamic Azad University, Tehran, Iran. Journal Article The evolution of fifth-generation cellular networks (5G) brings unprecedented improvements in speed, latency, and scalability, but also introduces significant new security challenges. While earlier studies have primarily focused on performance benchmarking or examined isolated vulnerabilities, there remains a lack of comprehensive, reproducible security evaluations of 5G core networks. This paper presents a scenario-based simulation study of three distinct denial-of-service (DoS) attacks targeting critical components of the 5G control plane. Using open-source tools such as Open5GS and UERANSIM, we demonstrate: (1) large-scale registration flooding that overloads both the next-generation NodeB (gNB) and the Access and Mobility Management Function (AMF); (2) AMF resource exhaustion through massive NGSetupRequest messages; and (3) tampering with a security-related parameter in the User Equipment (UE) registration process to disrupt authentication. The evaluation quantifies the impacts of Central Processing Unit (CPU) and Random Access Memory (RAM) under these attacks, showing that even commodity hardware testbeds can reveal critical vulnerabilities. Moreover, analysis of the logs collected during the attacks confirms the successful execution of each attack scenario. The findings highlight how scenario-based simulations effectively explore various 5G attack surfaces and underscore the necessity for targeted defense mechanisms to enhance the resilience of next-generation mobile networks. https://www.isecure-journal.com/article_240534_074bf84144d06560aa92fc65dafdc986.pdf