Ahmad, Liyanage, Shahabuddin, Ylianttila, and Gurtov
78
4.2.2 Security Threats and Recommendations by NGMN
The Next Generation Mobile Networks (NGMN) [7] provides recommendations for
5G based on the current network architectures, and the lacking security measures that
are either not implemented or available. The recommendation highlights the cautionary notes. These include the infancy of 5G with many uncertainties, lack of defined
design concepts and the unknown end‐to‐end (E2E) and subsystem architectures.
The recommendation highlights the limitations in the access networks and cyber‐
attacks against the network infrastructure. The details of the security limitations
and recommendations can found in [7]. Below we highlight the key points in the
recommendations:
● Flash network traffic: It is known that the number of end user devices will grow
exponentially in 5G, thus the large‐scale events may cause significant changes in the
network traffic patterns that could be either accidental or malicious. Therefore, it is
recommended that the 5G systems must minimize large swings in traffic usage and
provide resilience whenever such surges occur, while maintaining an acceptable level
of performance.
● Security of radio interface keys: In the previous generations, even in 4G, keys for the
radio interface encryption are generated in the home network and sent to the visited
network over unsecure links causing a clear point of exposure of the keys. It is recommended that the keys are either not sent over those links, such as SS7/Diameter, or
properly secured.
● User plane integrity: 3G and 4G do not provide cryptographic integrity protection for
the user data plane, though these provide protection to some signaling messages. It is
recommended to provide the protection at the transport or application layer that
terminates beyond the mobile network. The exception to this could be network level
security for resource constrained IoT or latency sensitive 5G devices and services.
Application level E2E security may involve too much overhead for data transmission
in the packet headers and handshakes.
● Mandated security in the network: There are service‐driven constraints on the security architecture leading to optional use of security measures. Unfortunately, these
constraints undermine system‐lever security assumptions and cannot be completely
eliminated. The challenge increases in multi‐operator scenarios where one operator
suffers due to inadequate measures by other. Therefore it is highly recommended that
some level, if not all, must be mandated in 5G after proper investigation to recognize
the most critical security challenges.
● Consistency in subscriber level security policies: There is a need that the user‐security
parameters are not changed due to roaming from one operator network to the other.
In the case of highly mobile users, it is highly possible that all the security services are
not updated frequently and per‐user basis as the user moves from place to place or
from one operator network to another in the case of roaming. When a user from one
operator moves to another and is using latency sensitive services, the services might
be provided through the edge of the visited operator network such as in Mobile Edge
Computing (MEC). So will the security or the security of the service being used be
automatically offered or configured at the new location? This needs security policy
sharing among network operators on a much faster scale to secure user traffic with
roaming. The recommendation discusses the possibility of using virtualization
78
4.2.2 Security Threats and Recommendations by NGMN
The Next Generation Mobile Networks (NGMN) [7] provides recommendations for
5G based on the current network architectures, and the lacking security measures that
are either not implemented or available. The recommendation highlights the cautionary notes. These include the infancy of 5G with many uncertainties, lack of defined
design concepts and the unknown end‐to‐end (E2E) and subsystem architectures.
The recommendation highlights the limitations in the access networks and cyber‐
attacks against the network infrastructure. The details of the security limitations
and recommendations can found in [7]. Below we highlight the key points in the
recommendations:
● Flash network traffic: It is known that the number of end user devices will grow
exponentially in 5G, thus the large‐scale events may cause significant changes in the
network traffic patterns that could be either accidental or malicious. Therefore, it is
recommended that the 5G systems must minimize large swings in traffic usage and
provide resilience whenever such surges occur, while maintaining an acceptable level
of performance.
● Security of radio interface keys: In the previous generations, even in 4G, keys for the
radio interface encryption are generated in the home network and sent to the visited
network over unsecure links causing a clear point of exposure of the keys. It is recommended that the keys are either not sent over those links, such as SS7/Diameter, or
properly secured.
● User plane integrity: 3G and 4G do not provide cryptographic integrity protection for
the user data plane, though these provide protection to some signaling messages. It is
recommended to provide the protection at the transport or application layer that
terminates beyond the mobile network. The exception to this could be network level
security for resource constrained IoT or latency sensitive 5G devices and services.
Application level E2E security may involve too much overhead for data transmission
in the packet headers and handshakes.
● Mandated security in the network: There are service‐driven constraints on the security architecture leading to optional use of security measures. Unfortunately, these
constraints undermine system‐lever security assumptions and cannot be completely
eliminated. The challenge increases in multi‐operator scenarios where one operator
suffers due to inadequate measures by other. Therefore it is highly recommended that
some level, if not all, must be mandated in 5G after proper investigation to recognize
the most critical security challenges.
● Consistency in subscriber level security policies: There is a need that the user‐security
parameters are not changed due to roaming from one operator network to the other.
In the case of highly mobile users, it is highly possible that all the security services are
not updated frequently and per‐user basis as the user moves from place to place or
from one operator network to another in the case of roaming. When a user from one
operator moves to another and is using latency sensitive services, the services might
be provided through the edge of the visited operator network such as in Mobile Edge
Computing (MEC). So will the security or the security of the service being used be
automatically offered or configured at the new location? This needs security policy
sharing among network operators on a much faster scale to secure user traffic with
roaming. The recommendation discusses the possibility of using virtualization