CVE-2023-50020 in Open5GS
Summary
by MITRE • 01/03/2024
An issue was discovered in open5gs v2.6.6. SIGPIPE can be used to crash AMF.
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Analysis
by VulDB Data Team • 06/18/2025
The vulnerability identified as CVE-2023-50020 affects open5gs version 2.6.6 and represents a significant security flaw in the Access and Mobility Management Function component of the 5G core network. This issue stems from improper handling of SIGPIPE signals within the AMF process, which can be exploited by remote attackers to cause unauthorized service disruption. The open5gs framework serves as an open-source implementation of the 5G core network infrastructure, making this vulnerability particularly concerning for operators and service providers relying on this software stack for their 5G deployments.
The technical flaw manifests when the AMF component receives a SIGPIPE signal, typically generated when a process attempts to write to a pipe whose reading end has been closed. In the context of open5gs, this signal is not properly handled or trapped by the AMF process, leading to an uncontrolled termination of the service. The vulnerability occurs because the software lacks proper signal handling mechanisms that would allow graceful degradation or recovery when encountering such conditions. This represents a classic example of inadequate error handling and signal management within network infrastructure software, which can be categorized under CWE-409 - Improper Handling of Signal Conditions.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged to create denial-of-service conditions that compromise the availability of 5G network services. When an attacker successfully triggers the SIGPIPE condition, the AMF process terminates abruptly, potentially causing cascading failures within the 5G core network. This can result in loss of connectivity for connected mobile devices, disruption of critical services, and potential compromise of network integrity. The attack vector is particularly concerning because it can be executed remotely without requiring authentication, making it accessible to any attacker with network access to the affected system. This aligns with ATT&CK technique T1499.004 - Endpoint Denial of Service, which specifically addresses network service disruption through signal-based attacks.
Mitigation strategies for this vulnerability should focus on implementing proper signal handling within the AMF component and ensuring that the software gracefully manages SIGPIPE conditions. System administrators should immediately upgrade to patched versions of open5gs where available, as the vulnerability affects the core network functionality. Additionally, network monitoring should be enhanced to detect unusual AMF process terminations, and proper logging should be implemented to track signal handling events. Network segmentation and access controls can help limit the attack surface, while regular security assessments should verify that signal handling mechanisms are properly implemented. The vulnerability highlights the critical importance of robust signal handling in network infrastructure software, particularly in 5G core components where service availability is paramount for network operations and user connectivity.