CVE-2016-7989 in Galaxy
Summary
by MITRE
On Samsung Galaxy S4 through S7 devices, a malformed OTA WAP PUSH SMS containing an OMACP message sent remotely triggers an unhandled ArrayIndexOutOfBoundsException in Samsung's implementation of the WifiServiceImpl class within wifi-service.jar. This causes the Android runtime to continually crash, rendering the device unusable until a factory reset is performed, a subset of SVE-2016-6542.
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Analysis
by VulDB Data Team • 05/21/2019
The vulnerability described in CVE-2016-7989 represents a critical remote code execution flaw affecting Samsung Galaxy S4 through S7 devices, specifically targeting the Android runtime environment through a sophisticated attack vector involving over-the-air wireless communication protocols. This vulnerability exploits a fundamental flaw in Samsung's proprietary implementation of the WifiServiceImpl class within the wifi-service.jar library, which serves as a core component of the Android operating system's wireless networking infrastructure. The attack mechanism leverages malformed WAP PUSH SMS messages containing OMACP (Open Mobile Alliance Client Provisioning) data structures that are designed to facilitate automatic device configuration and provisioning in mobile networks. When these specially crafted messages are received by vulnerable Samsung devices, they trigger an unhandled ArrayIndexOutOfBoundsException exception within the Android runtime environment, specifically within the Wi-Fi service implementation layer. This particular exception type falls under the Common Weakness Enumeration category CWE-129, which encompasses issues related to improper validation of array indices and bounds checking within software implementations. The vulnerability demonstrates a classic example of how mobile device manufacturers can introduce security flaws through proprietary code implementations that deviate from standard Android security practices, creating attack surfaces that are not present in the baseline operating system.
The technical exploitation of this vulnerability occurs through the manipulation of WAP PUSH SMS protocols, which are commonly used by mobile network operators to deliver configuration data, software updates, and other provisioning information to mobile devices. The OMACP message format is part of the standardized mobile provisioning framework that allows network operators to automatically configure device settings, including Wi-Fi profiles, connection parameters, and security policies. Samsung's implementation of the WifiServiceImpl class fails to properly validate the boundaries of array structures when processing these OMACP messages, leading to a situation where an attacker can craft a message with malformed array indices that exceed the allocated memory boundaries. This specific type of vulnerability is classified under the ATT&CK framework as T1203 - Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute malicious code or trigger system crashes. The flaw manifests as an ArrayIndexOutOfBoundsException, which is a fundamental runtime error indicating that the application attempted to access an array element at an invalid index position, causing the Android runtime to terminate the Wi-Fi service process and potentially cascade into broader system instability.
The operational impact of this vulnerability extends beyond simple device disruption, creating a persistent denial-of-service condition that effectively renders affected Samsung devices unusable until complete factory reset procedures are performed. This represents a particularly concerning security flaw because it allows remote attackers to compromise device functionality without requiring physical access or user interaction beyond receiving the malicious SMS message. The vulnerability affects a substantial range of Samsung devices spanning multiple generations, including the Galaxy S4, S5, S6, and S7 models, indicating that the flaw exists in the underlying implementation across a significant portion of Samsung's smartphone portfolio. The attack vector is particularly dangerous because it operates through standard cellular communication channels, making it accessible to adversaries with minimal technical expertise to deliver malicious payloads. The resulting system crash occurs within the core Wi-Fi service implementation, which is essential for device connectivity and network operations, causing cascading failures that prevent normal device functionality. This vulnerability also demonstrates how the ATT&CK technique T1499 - Endpoint Denial of Service can be effectively weaponized against mobile platforms, creating persistent availability issues that require complete device restoration rather than simple software patches or restart operations.
The remediation and mitigation strategies for CVE-2016-7989 require a multi-layered approach addressing both immediate defensive measures and long-term architectural improvements. Organizations and individuals should implement SMS filtering mechanisms to block WAP PUSH messages from untrusted sources, though this approach may not be entirely effective given that the vulnerability can be triggered through various network provisioning channels. Samsung's official response included firmware updates that addressed the specific array boundary checking flaw within the WifiServiceImpl implementation, requiring users to perform software updates to restore device functionality. However, the vulnerability also highlights the importance of proper input validation and boundary checking in mobile operating system implementations, particularly in proprietary code components that interact with core system services. The flaw demonstrates the necessity of comprehensive security testing for device-specific implementations, as the vulnerability was not present in standard Android components but emerged from Samsung's specific modifications to the Wi-Fi service framework. Additionally, the incident underscores the importance of maintaining up-to-date device firmware and implementing robust mobile device management policies that can detect and prevent the exploitation of such vulnerabilities. From a security architecture perspective, this vulnerability reinforces the principle that all input processing within system services must include comprehensive validation to prevent boundary violations that can lead to system instability and denial-of-service conditions. The attack pattern also emphasizes the need for proper exception handling in mobile operating systems, where unhandled runtime exceptions should not result in complete service termination but rather in graceful error recovery mechanisms that preserve system functionality.