CVE-2016-4030 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 have unintended availability of the modem in USB configuration number 2 within the secure lockscreen state, allowing an attacker to make phone calls, send text messages, or issue commands, 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, exposing a critical security flaw in the USB peripheral configuration during secure lockscreen states. The issue stems from an improper implementation of USB host mode permissions where the modem interface remains accessible even when the device is locked, creating an unauthorized attack surface that bypasses the device's security controls. The vulnerability specifically impacts USB configuration number 2, which contains modem functionality that should be restricted during locked states but remains active and accessible to unauthorized users.
The technical flaw manifests as a failure in the Android security model's USB permission handling mechanism, where the system does not properly enforce access controls for USB modem interfaces when the device is in secure lockscreen mode. This represents a clear violation of the principle of least privilege and demonstrates a failure in the device's USB security architecture. According to CWE-284, this vulnerability maps directly to inadequate access control mechanisms, specifically the improper restriction of access to USB peripheral devices during locked states. The flaw allows attackers to exploit the USB interface to execute arbitrary commands through the modem, enabling unauthorized communication activities and potential command execution on the device.
The operational impact of this vulnerability is significant, as it provides attackers with the ability to perform critical phone functions without authentication or authorization. An attacker with physical access to the device can exploit this weakness to make unauthorized phone calls, send text messages, or issue commands to the device's modem, potentially leading to financial loss, privacy violations, and data exfiltration. The vulnerability is particularly concerning because it operates entirely within the physical security boundary of the device, requiring no network connectivity or complex attack vectors. This aligns with ATT&CK technique T1059.005 for command and scripting interpreter and T1071.004 for application layer protocol, as the attacker can leverage the modem interface to execute commands and communicate through legitimate device functions.
The security implications extend beyond simple unauthorized communications, as this vulnerability could potentially enable more sophisticated attacks such as SIM card cloning, location tracking, or data manipulation through the modem interface. The fact that this affects multiple device models suggests a systemic issue in Samsung's USB security implementation rather than an isolated bug, indicating that the vulnerability may be present in the underlying Android framework or kernel USB drivers. This type of vulnerability is particularly dangerous in enterprise environments where lost or stolen devices could be exploited by attackers to maintain persistent access or conduct unauthorized operations. Organizations should consider this vulnerability when implementing device security policies and may need to update their incident response procedures to account for potential unauthorized modem access during locked states. The vulnerability also highlights the importance of proper USB security configuration management and the need for comprehensive testing of USB interfaces during secure lockscreen states to prevent similar issues in future device implementations.