CVE-2024-39343: Samsung Exynos Firmware DoS Vulnerability

CVE-2024-39343 Overview

A denial of service vulnerability has been discovered in Samsung Mobile Processor and Wearable Processor Exynos chipsets affecting multiple processor generations and modem firmware. The vulnerability exists in the baseband software where improper length validation in the MM (Mobility Management) module can be exploited by remote attackers to cause a denial of service condition on affected devices.

Critical Impact

Remote attackers can exploit this baseband vulnerability over the network to disrupt cellular connectivity on Samsung Galaxy devices and wearables using affected Exynos processors, potentially rendering communication services unavailable.

Affected Products

• Samsung Exynos 2100, 1280, 2200, 1330, 1380, 1480, 2400 Mobile Processors
• Samsung Exynos 9110 Wearable Processor
• Samsung Exynos Modem 5123 and Modem 5300 Firmware

Discovery Timeline

• 2024-12-02 - CVE-2024-39343 published to NVD
• 2025-07-01 - Last updated in NVD database

Technical Details for CVE-2024-39343

Vulnerability Analysis

This vulnerability stems from improper input validation (CWE-1284) in Samsung's Exynos baseband firmware. The MM (Mobility Management) module, which handles core cellular network procedures such as location updates, authentication, and connection management, fails to properly validate length fields in incoming messages. When processing malformed MM protocol data units with invalid length specifications, the baseband software does not perform adequate boundary checking, leading to a denial of service condition.

The network-accessible nature of this vulnerability is particularly concerning as it affects the baseband processor—a critical component that operates independently from the main application processor. Exploitation could disrupt cellular connectivity without requiring any user interaction or authentication, affecting device communication capabilities.

Root Cause

The root cause is improper validation of length parameters within the Mobility Management module of the baseband software. The MM module processes various 3GPP protocol messages for cellular network operations, and the length fields within these messages are not being properly validated against expected boundaries before processing. This improper input validation allows specially crafted messages with malicious length values to cause unexpected behavior in the baseband processor.

Attack Vector

The attack can be executed remotely over the cellular network. An attacker with the ability to send crafted cellular signaling messages (potentially through a rogue base station or by compromising network infrastructure) can target vulnerable devices. The attack requires no user interaction and no prior authentication, though exploitation complexity is considered high due to the specialized knowledge and infrastructure required to craft and deliver malicious MM protocol messages.

The vulnerability affects the confidentiality and integrity of the device at a limited level, while having a high impact on availability. Successful exploitation results in denial of service affecting the device's cellular communication capabilities.

Detection Methods for CVE-2024-39343

Indicators of Compromise

• Unexpected loss of cellular connectivity or frequent baseband crashes on affected Samsung devices
• Device radio/modem restarting without user action or apparent cause
• Abnormal battery drain associated with baseband recovery operations
• Log entries indicating MM module errors or baseband exceptions

Detection Strategies

• Monitor device logs for baseband-related crashes or restarts, particularly those associated with MM module operations
• Implement network-level monitoring for anomalous cellular signaling patterns that could indicate exploitation attempts
• Deploy mobile device management (MDM) solutions capable of detecting abnormal device behavior patterns
• Track firmware version compliance across enterprise mobile device fleets

Monitoring Recommendations

• Establish baseline cellular connectivity metrics for managed devices to identify anomalies
• Configure alerting for repeated baseband failures across multiple devices in the same geographic area
• Monitor Samsung security bulletin releases for patch availability and deployment status
• Implement endpoint detection solutions capable of correlating device health with potential attack indicators

How to Mitigate CVE-2024-39343

Immediate Actions Required

• Review and apply the latest Samsung firmware updates for all affected Exynos-based devices
• Prioritize patching for devices in high-security environments or those handling sensitive communications
• Inventory all Samsung Galaxy devices and wearables using affected Exynos processors within the organization
• Consider temporary mitigation through Wi-Fi-only operation for critical devices until patches are applied

Patch Information

Samsung has released security updates to address this vulnerability. Organizations should obtain the latest firmware updates through Samsung's official channels. Refer to the Samsung Product Security Updates page for detailed patch information and affected device lists.

For enterprise deployments, coordinate with mobile device management solutions to push firmware updates systematically across the device fleet.

Workarounds

• Where feasible, limit cellular network exposure by utilizing Wi-Fi connectivity for affected devices
• Consider disabling cellular radio on non-essential devices until patches can be applied
• Implement network segmentation to isolate critical communication workflows from potentially affected devices
• Maintain backup communication channels for critical operations that do not rely on affected Samsung devices

# Example: Check device firmware version on Android (via ADB)
adb shell getprop ro.build.version.baseband
# Compare output against Samsung's security bulletin to verify patch status