CVE-2023-49391 in free5GC
Summary
by MITRE • 12/22/2023
An issue was discovered in free5GC version 3.3.0, allows remote attackers to execute arbitrary code and cause a denial of service (DoS) on AMF component via crafted NGAP message.
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Analysis
by VulDB Data Team • 09/12/2024
The vulnerability identified as CVE-2023-49391 affects the free5GC 3.3.0 implementation specifically within the Access and Mobility Management Function (AMF) component. This represents a critical security flaw that enables remote attackers to gain unauthorized execution capabilities and disrupt service availability. The AMF serves as a crucial element in 5G networks responsible for managing access and mobility of user equipment, making this vulnerability particularly concerning for network infrastructure security. The flaw manifests through the processing of crafted NGAP (Next Generation Application Protocol) messages, which are fundamental to communication between 5G network functions.
The technical root cause of this vulnerability stems from inadequate input validation and sanitization within the AMF's NGAP message handling mechanism. When the AMF receives malformed or specially crafted NGAP messages, it fails to properly validate the message structure and content before processing. This insufficient validation creates an opportunity for attackers to inject malicious payloads that can trigger unexpected behavior within the AMF component. The vulnerability aligns with CWE-129, which addresses issues related to insufficient input validation, and CWE-787, concerning out-of-bounds write operations that can occur when processing malformed input data. The flaw essentially allows attackers to manipulate the AMF's memory operations through carefully constructed message parameters.
The operational impact of CVE-2023-49391 extends beyond simple code execution to encompass full denial of service conditions that can compromise entire 5G network segments. Remote attackers can leverage this vulnerability to either execute arbitrary code on the affected AMF system, potentially gaining administrative control over network functions, or to induce denial of service conditions that prevent legitimate users from accessing network services. This dual nature of exploitation makes the vulnerability particularly dangerous as it can be used for both offensive operations and network disruption attacks. The attack surface is significant since the AMF component typically operates in network environments where it must accept connections from various network elements including gNodeBs and other 5G core network functions.
From a threat modeling perspective, this vulnerability maps to several ATT&CK techniques including T1059.001 for command and script interpreter execution, T1499.004 for network disruption, and T1566.001 for spearphishing attachments. The attack chain typically begins with reconnaissance to identify vulnerable free5GC installations, followed by crafting of malicious NGAP messages designed to exploit the input validation gaps. Network traffic monitoring and intrusion detection systems should be configured to detect anomalous NGAP message patterns that could indicate exploitation attempts. Organizations using free5GC versions prior to 3.3.1 should immediately implement mitigations including network segmentation, traffic filtering, and comprehensive monitoring of NGAP message exchanges to prevent exploitation.
The recommended mitigation strategies include immediate deployment of the patched free5GC version 3.3.1 which addresses the input validation issues in the AMF component. Network administrators should also implement strict NGAP message validation rules at network boundaries and consider deploying network access control lists to restrict communication to trusted network elements only. Additional protective measures include regular security assessments of 5G network components, implementation of network monitoring solutions specifically designed to detect malformed NGAP traffic, and maintaining detailed audit logs of all AMF interactions. The vulnerability underscores the importance of secure coding practices in 5G network implementations and highlights the need for comprehensive security testing of network function components before deployment in production environments. Organizations should also consider implementing zero-trust network architectures where all network communications are validated and authenticated regardless of their source location.