CVE-2016-4031 in Galaxy S4
Summary
by MITRE
Samsung SM-G920F build G920FXXU2COH2 (Galaxy S6), SM-N9005 build N9005XXUGBOK6 (Galaxy Note 3), GT-I9192 build I9192XXUBNB1 (Galaxy S4 mini), GT-I9195 build I9195XXUCOL1 (Galaxy S4 mini LTE), and GT-I9505 build I9505XXUHOJ2 (Galaxy S4) devices allow attackers to send AT commands by plugging the device into a Linux host, aka SVE-2016-5301.
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Analysis
by VulDB Data Team • 08/30/2020
This vulnerability affects multiple Samsung Android devices including the Galaxy S6, Note 3, and various Galaxy S4 models, representing a critical security flaw in the device's USB communication protocols. The vulnerability stems from the improper handling of AT commands when devices are connected to Linux hosts through USB interfaces, creating an attack vector that allows malicious actors to execute arbitrary commands on the affected devices. The issue is classified as a USB-based attack that leverages the device's default USB configuration to establish unauthorized communication channels with host systems.
The technical flaw resides in the Android USB host mode implementation where the device fails to properly validate or restrict AT command execution when connected to a Linux host. This allows attackers to send AT commands directly to the device's modem or communication processor through the USB interface, bypassing normal security controls and authentication mechanisms. The vulnerability specifically affects devices running older Android versions where USB host mode permissions are not properly enforced, creating a persistent attack surface that remains active as long as the device remains connected to a compromised host system.
The operational impact of this vulnerability is significant as it enables attackers to perform various malicious activities including but not limited to remote device control, data extraction, command injection, and potential escalation of privileges. Attackers can leverage this vulnerability to gain unauthorized access to device functionalities such as SMS messaging, phone calls, network connectivity controls, and potentially access sensitive user data stored on the device. The attack requires physical access to the device or the ability to connect it to a malicious host, making it particularly dangerous in scenarios where devices are left unattended or in environments where USB connections are frequently established.
The vulnerability aligns with CWE-284 which addresses improper access control in USB communication protocols, and represents a specific instance of privilege escalation through USB host mode exploitation. From an ATT&CK framework perspective, this vulnerability maps to T1059.005 for command and scripting interpreter usage and T1071.004 for application layer protocols involving USB communication. The attack chain typically involves connecting the vulnerable device to a compromised Linux host, establishing USB communication, and then executing malicious AT commands through the USB interface to achieve the desired malicious outcomes.
Mitigation strategies should focus on implementing proper USB security policies including disabling USB host mode for untrusted hosts, updating device firmware to versions that address the vulnerability, and employing device management solutions that can monitor and control USB connections. Organizations should also consider implementing network-based security controls to detect and prevent unauthorized USB communications, along with regular security assessments to identify and remediate similar vulnerabilities in their device fleets. The vulnerability underscores the importance of secure USB implementation practices and proper access control enforcement in mobile device security architectures.