CVE-2015-3834 in Android
Summary
by MITRE
Multiple integer overflows in the BnHDCP::onTransact function in media/libmedia/IHDCP.cpp in libstagefright in Android before 5.1.1 LMY48I allow attackers to execute arbitrary code via a crafted application that uses HDCP encryption, leading to a heap-based buffer overflow, aka internal bug 20222489.
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Analysis
by VulDB Data Team • 02/04/2018
The vulnerability identified as CVE-2015-3834 represents a critical security flaw within the Android media framework that specifically affects devices running Android versions prior to 5.1.1 LMY48I. This vulnerability resides in the BnHDCP::onTransact function located within the media/libmedia/IHDCP.cpp file of the libstagefright library, which serves as a foundational component for multimedia processing in Android devices. The issue stems from improper input validation and handling of integer values during HDCP (High-bandwidth Digital Content Protection) encryption operations, creating a pathway for malicious code execution through carefully crafted applications that leverage HDCP functionality.
The technical exploitation of this vulnerability occurs through integer overflow conditions that manifest when the BnHDCP::onTransact function processes HDCP-related transactions. When an attacker crafts a malicious application that utilizes HDCP encryption, the function fails to properly validate integer inputs, leading to arithmetic overflow conditions that can result in heap-based buffer overflows. These buffer overflows occur because the system allocates memory based on incorrectly calculated integer values, allowing attackers to overwrite adjacent memory locations with malicious data. The vulnerability specifically targets the heap memory management within the libstagefright framework, making it particularly dangerous as it can lead to arbitrary code execution with the privileges of the affected process, typically the media framework service.
The operational impact of CVE-2015-3834 extends beyond simple privilege escalation, as it provides attackers with a sophisticated vector for compromising Android devices through legitimate media processing pathways. This vulnerability can be exploited through seemingly benign applications that utilize HDCP encryption, making detection and prevention challenging for end users and security administrators. The attack surface is particularly concerning given that HDCP is commonly used in multimedia applications and streaming services, meaning that a wide range of legitimate applications could potentially serve as delivery mechanisms for exploitation. The vulnerability's classification aligns with CWE-190, which addresses integer overflow conditions, and can be mapped to ATT&CK technique T1059.007 for process injection and T1068 for local privilege escalation, as the exploitation typically requires local access to execute malicious payloads within the media framework context.
Mitigation strategies for CVE-2015-3834 primarily focus on updating Android devices to versions 5.1.1 LMY48I or later, where the vulnerability has been patched through proper integer overflow handling in the affected function. System administrators should implement comprehensive patch management programs to ensure all Android devices within their environments receive timely security updates. Additionally, network-level monitoring should be enhanced to detect unusual HDCP-related traffic patterns that might indicate exploitation attempts, though this approach remains limited due to the nature of the vulnerability occurring within legitimate media processing functions. Organizations should also consider implementing application whitelisting policies that restrict the execution of potentially malicious applications that might leverage HDCP functionality for exploitation. The patch addresses the root cause by implementing proper integer bounds checking and validation within the BnHDCP::onTransact function, preventing the arithmetic overflow conditions that lead to the heap-based buffer overflow and subsequent arbitrary code execution capabilities.