CVE-2015-3843 in Android
Summary
by MITRE
The SIM Toolkit (STK) framework in Android before 5.1.1 LMY48I allows attackers to (1) intercept or (2) emulate unspecified Telephony STK SIM commands via an application that sends a crafted Intent, related to com/android/internal/telephony/cat/AppInterface.java, aka internal bug 21697171.
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Analysis
by VulDB Data Team • 02/03/2018
The vulnerability identified as CVE-2015-3843 resides within the SIM Toolkit framework of Android operating systems prior to version 5.1.1 LMY48I, representing a critical security flaw that exposes the telephony subsystem to unauthorized command interception and emulation attacks. This vulnerability specifically affects the com/android/internal/telephony/cat/AppInterface.java component, which serves as the interface layer between the SIM card and the Android telephony services, creating an attack surface where malicious applications can manipulate or monitor SIM commands intended for legitimate telephony applications.
The technical exploitation of this vulnerability occurs through the manipulation of Intent objects, which are Android's messaging system for inter-application communication. Attackers can craft malicious applications that send specially formatted Intents to the SIM Toolkit framework, enabling them to either intercept legitimate Telephony STK commands that should only be processed by authorized applications or to emulate these commands entirely. This capability fundamentally undermines the security model of SIM card communication, as it allows unauthorized parties to masquerade as legitimate SIM card applications or to monitor sensitive telephony operations that typically require elevated privileges and secure processing.
The operational impact of this vulnerability extends beyond simple data interception, as it can enable sophisticated attacks including unauthorized network access, SIM card cloning, and potential surveillance of mobile communications. The ability to emulate SIM commands means attackers can potentially manipulate the mobile device's behavior in ways that could compromise user privacy, enable unauthorized roaming, or facilitate more complex attacks such as man-in-the-middle operations against cellular communications. This vulnerability particularly affects devices that rely on SIM card-based authentication and authorization mechanisms, making it a significant threat to mobile security infrastructure.
The security implications of this vulnerability align with CWE-215, which addresses the exposure of sensitive information through improper handling of system-level interfaces, and can be mapped to ATT&CK technique T1059.001 for the use of command and scripting interpreters, as attackers can leverage the framework to execute unauthorized commands through crafted Intents. Organizations and users should implement immediate mitigations including updating to Android 5.1.1 or later versions, applying relevant security patches, and monitoring for unauthorized applications that may attempt to exploit this vulnerability. Additionally, network operators should consider implementing additional security measures to detect and prevent unauthorized SIM command manipulation, as this vulnerability can potentially compromise the integrity of mobile network security protocols and user communications.