CVE-2024-29153 in Exynos 9820
Summary
by MITRE • 07/09/2024
A vulnerability was discovered in Samsung Mobile Processor, Wearable Processor, and Modems with versions Exynos 9820, Exynos 9825, Exynos 980, Exynos 990, Exynos 850, Exynos 1080, Exynos 2100, Exynos 2200, Exynos 1280, Exynos 1380, Exynos 1330, Exynos 9110, Exynos W920, Exynos W930, Exynos Modem 5123, and Exynos Modem 5300 that involves incorrect autorization of LTE NAS messages and leads to downgrading to lower network generations and repeated DDOS.
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Analysis
by VulDB Data Team • 06/14/2025
This vulnerability affects Samsung mobile processors and wearable devices that utilize specific Exynos chipsets including the 9820, 9825, 980, 990, 850, 1080, 2100, 2200, 1280, 1380, 1330, 9110, W920, W930, and various modem versions. The flaw resides in the LTE Network Access Server (NAS) message handling mechanism where improper authorization checks allow malicious actors to manipulate network connection parameters. This vulnerability maps to CWE-285 which specifically addresses insufficient authorization issues in network protocols. The technical implementation involves the processor's inability to properly validate the authenticity and integrity of incoming LTE NAS messages, creating a pathway for unauthorized network state modifications.
The operational impact of this vulnerability is significant as it enables attackers to force devices into downgrading to less secure network generations such as 3G or 2G networks, thereby reducing encryption levels and exposing communication channels to interception. Additionally, the flaw allows for repeated denial-of-service attacks by continuously forcing network reconfiguration, effectively disrupting legitimate network connectivity for affected devices. This type of attack pattern aligns with ATT&CK technique T1499.004 which covers network denial of service attacks through manipulation of network protocols. The repeated nature of the DoS attacks suggests that the vulnerability can be exploited multiple times without requiring device reboot or network reconfiguration.
The root cause stems from inadequate validation of network management messages within the modem firmware that governs cellular connectivity. When legitimate NAS messages are received, the system should verify their source authenticity and ensure they comply with expected protocol sequences before executing any network state changes. The vulnerability allows attackers to craft malicious messages that bypass these validation checks, effectively impersonating legitimate network management entities. This represents a critical failure in the authentication and authorization framework that should exist between the device's cellular radio and network management components. The affected devices range from smartphones and tablets to wearable devices, indicating a widespread impact across Samsung's product portfolio.
Mitigation strategies should include immediate firmware updates from Samsung to address the authorization flaw in the LTE NAS message processing. Network operators should implement monitoring for unusual network reconfiguration patterns that could indicate exploitation attempts. Device users should ensure their firmware is up to date and avoid connecting to networks when possible if suspicious activity is detected. Security teams should consider implementing network-level controls to detect and block malformed NAS messages that attempt to force network downgrades. The vulnerability demonstrates the importance of proper protocol implementation and validation in mobile network components, as highlighted in industry standards for secure mobile communications. Organizations should also conduct vulnerability assessments to identify other potential authorization gaps in their mobile network infrastructure and implement comprehensive monitoring for similar protocol manipulation attacks.