5G networks are designed with a clear separation between control and user planes, interfaces, and core functions—each expected to operate within isolated trust boundaries. When these boundaries are not properly enforced, malicious traffic from user equipment can traverse unintended paths and reach sensitive components. This work demonstrates how an attacker-controlled UE can exploit such weaknesses using protocol tunneling and network boundary bridging to bypass isolation and interact with internal elements of the 5G core.

Open-Radio Access Network (O-RAN) is the next evolutionary step in mobile network architecture and operations and the Near-Real Time RAN Intelligent Controller (Near-RT RIC) plays a central role in the O-RAN architecture as it interfaces between the orchestration layer and next generation eNodeBs. In this paper we highlight the architectural weakness of a centralized controller in O-RAN by first drawing parallels with the Software-Defined Networking (SDN) controller. We then present a two part security evaluation of two open-source Near-RT RICs (μONOS and OSC), focused on the newly introduced A1 interface of the Near-RT RIC. In the first part of our evaluation, we evaluate the supply-chain risks of μONOS and OSC using off-the-shelf open-source dependency analysis and configuration file analysis tools. In the second part, we present our run-time security testing of the A1 API implemented by μONOS and OSC using our custom O-RAN A1 Interface Testing Tool (OAITT). Our supply-chain risk analysis shows that both the open-source Near-RT RICs we evaluated have multiple dependency risks and weak or insecure configurations. We identified 211 and 285 known dependency vulnerabilities in μONOS and OSC respectively of which 82 and 190 dependencies were rated as high CVSS respectively. The A1 interface contributed to a majority of the dependency risks in both Near-RT RICs. From a security misconfiguration perspective, we identified issues concerning access control, lack of encryption and poor secret management. Our run-time testing of OSC and μONOS revealed the following. First, both Near-RT RICs lack TLS for the A1 interface. Second, malicious Non-Real Time RAN Intelligent Controller (Non-RT RIC)s or rApps that reside in the Non-RT RIC could tamper with policies installed in the Near-RT RIC which can impact the availability of the O-RAN. Third, the A1 protocol could be exploited by Non-RT RICs for covert communication via the Near-RT RIC. Fourth, the A1 implementation by μONOS was vulnerable to degradation of service attacks (10-60s response time for GET requests) and a denial of service attack, the latter has been ethically reported and a fix is underway.

Cellular devices support various technical features and services for 2G, 3G, 4G and upcoming 5G networks. For example, these technical features contain physical layer throughput categories, radio protocol information, security algorithm, carrier aggregation bands and type of services such as GSM-R, Voice over LTE etc. In the cellular security standardisation context, these technical features and network services termed as device capabilities and exchanged with the network during the device registration phase. In this paper, we study device capabilities information specified for 4G and 5G devices and their role in establishing security association between the device and network. Our research results reveal that device capabilities are exchanged with the network before the authentication stage without any protection and not verified by the network. Consequently, we present three novel classes of attacks exploiting unprotected device capabilities information in 4G and upcoming 5G networks - identification attacks, bidding down attacks, and battery drain attacks against cellular devices. We implement proof-of-concept attacks using low-cost hardware and software setup to evaluate their impact against commercially available 4G devices and networks. We reported identified vulnerabilities to the relevant standardisation bodies and provide countermeasure to mitigate device capabilities attacks in 4G and upcoming 5G networks.

Abstract Mobile communications are used by more than two-thirds of the world population who expect security and privacy guarantees. The 3rd Generation Partnership Project (3GPP) responsible for the worldwide standardization of mobile communication has designed and mandated the use of the AKA protocol to protect the subscribers’ mobile services. Even though privacy was a requirement, numerous subscriber location attacks have been demonstrated against AKA, some of which have been fixed or mitigated in the enhanced AKA protocol designed for 5G. In this paper, we reveal a new privacy attack against all variants of the AKA protocol, including 5G AKA, that breaches subscriber privacy more severely than known location privacy attacks do. Our attack exploits a new logical vulnerability we uncovered that would require dedicated fixes. We demonstrate the practical feasibility of our attack using low cost and widely available setups. Finally we conduct a security analysis of the vulnerability and discuss countermeasures to remedy our attack.

Mobile network operators choose Self Organizing Network (SON) concept as a cost-effective method to deploy LTE/4G networks and meet user expectations for high quality of service and bandwidth. The main objective of SON is to introduce automation into network management activities and reduce human intervention. SON enabled LTE networks heavily rely on the information acquired from mobile phones to provide self-configuration, self-optimization, and self-healing features. However, mobile phones can be attacked over-the-air using rogue base stations. In this paper, we carefully study SON related LTE/4G security specifications and reveal several vulnerabilities. Our key idea is to introduce a rogue eNodeB that uses legitimate mobile devices as a covert channel to launch attacks against SON enabled LTE networks.