CVE-2017-13256 in Android
Summary
by MITRE
In process_service_search_attr_req of sdp_server.cc, there is an out of bounds write due to a missing bounds check. This could lead to remote code execution with no additional execution privileges needed. User interaction is not needed for exploitation. Product: Android. Versions: 5.1.1, 6.0, 6.0.1, 7.0, 7.1.1, 7.1.2, 8.0, 8.1. Android ID: A-68817966.
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Analysis
by VulDB Data Team • 01/21/2020
The vulnerability identified as CVE-2017-13256 represents a critical out-of-bounds write flaw within the Bluetooth service discovery protocol implementation of Android systems. This issue resides in the sdp_server.cc file where the process_service_search_attr_req function fails to perform proper bounds checking on user-supplied data, creating a pathway for malicious input to overwrite adjacent memory regions. The flaw specifically affects Android versions ranging from 5.1.1 through 8.1, encompassing a significant portion of the mobile platform's ecosystem and affecting billions of devices worldwide. The vulnerability is classified under CWE-787, which describes out-of-bounds write conditions that can result in arbitrary code execution. This particular flaw demonstrates a classic buffer overflow pattern where insufficient input validation allows attackers to manipulate memory layout and potentially execute malicious code with the privileges of the Bluetooth service process.
The operational impact of this vulnerability extends beyond simple remote code execution as it represents a complete compromise of the device's security model without requiring any user interaction or elevated privileges. Attackers can exploit this vulnerability by sending specially crafted Bluetooth packets to a vulnerable Android device, triggering the out-of-bounds write condition that can be leveraged to overwrite critical memory structures including function pointers, return addresses, or other control data. The absence of user interaction requirements makes this vulnerability particularly dangerous as it enables automated exploitation through Bluetooth proximity attacks or even remote exploitation via Bluetooth mesh networks. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, as it provides a foundation for executing arbitrary code within the system context. The vulnerability's exploitation potential is further amplified by the fact that Bluetooth services typically run with elevated privileges and have direct access to system resources, making successful exploitation a critical security incident.
Mitigation strategies for CVE-2017-13256 must address both immediate patching requirements and broader architectural security improvements. Organizations should prioritize immediate deployment of Android security patches released by Google, specifically targeting the Bluetooth stack modifications that include proper bounds checking in the sdp_server.cc implementation. The fix typically involves implementing robust input validation mechanisms that check array indices against buffer boundaries before any memory operations occur, effectively preventing the out-of-bounds write condition. Beyond patching, security teams should consider implementing network segmentation controls to limit Bluetooth exposure, particularly in enterprise environments where devices may be exposed to untrusted networks. Device hardening measures including disabling unnecessary Bluetooth services, implementing Bluetooth access controls, and monitoring for anomalous Bluetooth traffic patterns can provide additional defense-in-depth layers. Security professionals should also conduct vulnerability assessments to identify any custom Bluetooth applications or services that might be similarly affected by buffer overflow conditions, ensuring comprehensive coverage of the attack surface. The vulnerability serves as a reminder of the critical importance of memory safety in embedded systems and mobile platforms, where Bluetooth protocols often operate with minimal sandboxing and direct hardware access, making proper bounds checking a fundamental requirement for system security.