CVE-2023-37008 in MME
Summary
by MITRE • 01/22/2025
Open5GS MME versions <= 2.6.4 contain a buffer overflow in the ASN.1 deserialization function of the S1AP handler. This buffer overflow causes type confusion in decoded fields, leading to invalid parsing and freeing of memory. An attacker may use this to crash an MME or potentially execute code in certain circumstances.
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Analysis
by VulDB Data Team • 01/29/2025
The vulnerability identified as CVE-2023-37008 affects Open5GS MME components running versions 2.6.4 and earlier, representing a critical security flaw in the mobile network infrastructure that handles signaling for 4G LTE networks. This issue resides within the S1AP handler's ASN.1 deserialization function, which processes signaling messages exchanged between the MME and eNodeB devices in the LTE ecosystem. The buffer overflow occurs during the parsing of structured data formats that are essential for maintaining communication between network elements, making this vulnerability particularly dangerous in production network environments where reliability and security are paramount.
The technical implementation of this vulnerability stems from improper bounds checking within the ASN.1 parsing routines that decode S1AP protocol messages. When maliciously crafted packets are received by the vulnerable MME, the deserialization process fails to validate the size of incoming data structures, allowing an attacker to overflow predetermined buffer boundaries. This type confusion error manifests when the application interprets data of one type as another, causing the memory management functions to process invalid pointers during the cleanup phase. The flaw specifically affects the handling of decoded fields where the application assumes certain data structures maintain predictable layouts, but malicious input disrupts these assumptions leading to unpredictable memory operations.
The operational impact of CVE-2023-37008 extends beyond simple service disruption to potentially enable remote code execution under specific conditions, making it a severe threat to mobile network operators. An attacker who successfully exploits this vulnerability can cause the MME process to crash repeatedly, resulting in denial of service for all subscribers connected to that network segment, or in more sophisticated attack scenarios, achieve arbitrary code execution that could compromise the entire network infrastructure. This vulnerability directly affects the core signaling functions of the LTE network, potentially enabling attackers to intercept communications, perform location tracking, or even gain access to other network components that depend on the MME for proper operation. The risk is amplified by the fact that S1AP messages are frequently transmitted and processed without extensive input validation, making this attack vector particularly accessible.
Network security professionals should implement immediate mitigations including updating to Open5GS MME version 2.6.5 or later where this vulnerability has been patched, and applying network segmentation controls to limit exposure of vulnerable MME instances. The fix addresses the buffer overflow by implementing proper bounds checking and input validation within the ASN.1 deserialization process, aligning with common software security practices outlined in the CWE-121 category for buffer overflow vulnerabilities. Organizations should also consider deploying intrusion detection systems that can identify malformed S1AP packets and monitor for unusual MME crash patterns that may indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1210 exploitation of remote services and T1499 network denial of service, highlighting the multi-faceted attack surface this flaw presents to network defenders. Regular security assessments and network monitoring should be enhanced to detect potential exploitation attempts, particularly in environments where the vulnerable software components are exposed to untrusted network traffic.