CVE-2023-32843 is a high-severity vulnerability affecting multiple MediaTek 5G modem chipsets, including models MT2735 through MT6990, specifically impacting modem versions NR15, NR16, and NR17. The vulnerability arises from improper error handling within the 5G modem's Radio Resource Control (RRC) message processing. An attacker can send specially crafted malformed RRC messages to the modem, triggering a system crash that results in a denial of service (DoS) condition. Notably, exploitation requires no authentication or user interaction, and can be performed remotely over the network. The vulnerability is classified under CWE-617 (Reachable Assertion), indicating that the system encounters an assertion failure due to unexpected input, leading to a crash. The CVSS v3.1 base score is 7.5, reflecting a high severity with network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability (system crash). While no known exploits are currently reported in the wild, the broad range of affected MediaTek modem chipsets—commonly integrated into smartphones, IoT devices, and embedded systems—makes this a significant threat. The lack of required privileges or user interaction lowers the barrier for attackers to cause service disruption remotely. The vulnerability could lead to temporary or persistent loss of cellular connectivity on affected devices, impacting communication reliability and potentially critical services relying on 5G connectivity. MediaTek has assigned patch ID MOLY01130204 to address this issue, though no direct patch links are provided in the data. Organizations and device manufacturers using these chipsets should prioritize deploying firmware updates once available to mitigate the risk.

For European organizations, the impact of CVE-2023-32843 can be substantial, especially for sectors relying heavily on 5G connectivity such as telecommunications providers, critical infrastructure, manufacturing with IoT deployments, and emergency services. A successful DoS attack could disrupt cellular network access on devices using vulnerable MediaTek modems, leading to communication outages, degraded operational capabilities, and potential safety risks. Enterprises deploying 5G-enabled devices for remote monitoring, control systems, or mobile workforce connectivity may experience interruptions affecting business continuity. Additionally, consumer devices with these modems could be targeted to cause widespread service degradation, indirectly impacting service providers and their customers. Given the remote and unauthenticated nature of the exploit, attackers could launch large-scale denial of service campaigns without needing physical access or user interaction, increasing the threat surface. The vulnerability may also be leveraged as part of multi-stage attacks to create distractions or degrade network availability during other malicious activities. The absence of known exploits in the wild currently reduces immediate risk, but the high severity and ease of exploitation necessitate proactive mitigation to prevent future incidents.

To mitigate CVE-2023-32843 effectively, European organizations and device manufacturers should: 1) Monitor MediaTek and device vendor advisories closely for the release of official firmware patches (MOLY01130204) addressing this vulnerability and prioritize timely deployment across all affected devices. 2) Implement network-level filtering to detect and block malformed or suspicious RRC messages where possible, using advanced intrusion detection/prevention systems tailored for 5G network traffic. 3) Employ network segmentation and isolate critical 5G-connected systems to limit the blast radius of potential DoS attacks. 4) Collaborate with mobile network operators to monitor for anomalous signaling traffic patterns indicative of exploitation attempts targeting MediaTek modems. 5) For managed IoT deployments, enforce strict device update policies and maintain an inventory of devices using affected chipsets to ensure comprehensive patch coverage. 6) Conduct regular security assessments and penetration tests simulating malformed RRC message attacks to validate the effectiveness of mitigations. 7) Educate security teams on the specifics of this vulnerability to enhance detection and incident response capabilities. These measures go beyond generic advice by focusing on proactive patch management, network-level defenses specific to 5G signaling, and operational controls tailored to the affected modem technology.