  IMSI (International Mobile Subscriber Identity) catchers, also known as
"Stingrays" or "cell site simulators," are rogue devices that pose a
significant threat to cellular network security [1]. IMSI catchers can
intercept and manipulate cellular communications, compromising the privacy and
security of mobile devices and their users. With the advent of 4G and 5G
networks, IMSI catchers have become more sophisticated and pose new challenges
to cellular network security [2]. This paper provides an overview of the impact
of IMSI catcher deployments on cellular network security in the context of 4G
and 5G networks. It discusses the challenges posed by IMSI catchers, including
the unauthorized collection of IMSI numbers, interception of communications,
and potential misuse of subscriber information. It also highlights the
potential consequences of IMSI catcher deployments, including the compromise of
user privacy, financial fraud, and unauthorized surveillance. The paper further
reviews the countermeasures that can be employed to mitigate the risks posed by
IMSI catchers. These countermeasures include network-based solutions such as
signal analysis, encryption, and authentication mechanisms, as well as
user-based solutions such as mobile applications and device settings. The paper
also discusses the limitations and effectiveness of these countermeasures in
the context of 4G and 5G networks. Finally, the paper identifies research gaps
and future directions for enhancing cellular network security against IMSI
catchers in the era of 4G and 5G networks. This includes the need for improved
encryption algorithms, authentication mechanisms, and detection techniques to
effectively detect and prevent IMSI catcher deployments. The paper also
emphasizes the importance of regulatory and policy measures to govern the
deployment and use of IMSI catchers to protect user privacy and security.
