CVE-2023-26496 in Exynos Modem 5123
Summary
by MITRE • 03/23/2023
An issue was discovered in Samsung Baseband Modem Chipset for Exynos Modem 5123, Exynos Modem 5300, Exynos 980, Exynos 1080, and Exynos Auto T5124. Memory corruption can occur due to improper checking of the parameter length while parsing the fmtp attribute in the SDP (Session Description Protocol) module.
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Analysis
by VulDB Data Team • 03/23/2023
The vulnerability identified as CVE-2023-26496 represents a critical memory corruption flaw within Samsung's baseband modem chipsets, affecting multiple generations including the Exynos Modem 5123, Exynos Modem 5300, Exynos 980, Exynos 1080, and Exynos Auto T5124. This issue stems from inadequate parameter length validation during the parsing of fmtp attributes within the Session Description Protocol module, creating a pathway for attackers to potentially execute arbitrary code or cause system instability. The affected chipsets are widely deployed in Samsung mobile devices and automotive systems, making this vulnerability particularly concerning from a cybersecurity perspective.
The technical flaw manifests in the improper handling of parameter length checks when processing the fmtp (format parameter) attribute within SDP messages. SDP is a standard protocol used for describing multimedia sessions and establishing communication parameters, commonly employed in VoIP and video conferencing applications. When the baseband modem receives a malformed SDP message containing an improperly sized fmtp attribute, the parsing routine fails to validate the input parameters correctly, leading to memory corruption. This memory corruption can result in buffer overflows, heap corruption, or stack corruption depending on how the malformed data is processed within the modem's memory management system. The vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of input buffers, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as exploitation could enable command execution within the modem's processing environment.
The operational impact of this vulnerability extends beyond simple device instability, as it could enable sophisticated attack vectors targeting the baseband processor that controls cellular communications, Wi-Fi, and Bluetooth functionalities. Attackers could potentially leverage this vulnerability to execute code remotely through malicious SDP messages delivered via SMS, MMS, or network-based communication protocols. The affected automotive systems with Exynos Auto T5124 chipsets present additional concerns, as they could be targeted to compromise vehicle communication systems and potentially enable unauthorized access to connected vehicle features. The vulnerability's exploitation could lead to complete system compromise, data exfiltration, or disruption of critical communication services, particularly affecting devices that rely heavily on cellular connectivity for their operations.
Mitigation strategies for CVE-2023-26496 should prioritize immediate firmware updates from Samsung, as the vendor has likely released patches addressing the parameter validation issue in the SDP parsing module. Network administrators and device security teams should implement monitoring for abnormal SDP message patterns and consider network segmentation to limit exposure. The vulnerability highlights the importance of robust input validation in embedded systems and underscores the need for comprehensive security testing of baseband processors. Organizations should also consider implementing network-based intrusion detection systems that can identify and block malicious SDP messages, while maintaining awareness of potential zero-day exploitation attempts. The issue emphasizes the critical nature of secure coding practices in embedded environments and the necessity for continuous security assessments of modem and baseband components.