CVE-2017-8251 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, in functions msm_isp_check_stream_cfg_cmd & msm_isp_stats_update_cgc_override, 'stream_cfg_cmd->num_streams' is not checked, and could overflow the array stream_cfg_cmd->stream_handle.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/14/2021
The vulnerability identified as CVE-2017-8251 affects Qualcomm products running Android versions that utilize the Linux kernel through the Code Aurora Forum. This flaw exists within the media streaming subsystem where two specific functions msm_isp_check_stream_cfg_cmd and msm_isp_stats_update_cgc_override fail to validate the number of streams parameter before processing. The issue stems from insufficient input validation where the value of stream_cfg_cmd->num_streams is not properly bounded, creating a potential buffer overflow condition that could be exploited by malicious actors.
The technical implementation of this vulnerability involves the improper handling of user-supplied data within kernel space functions. When the msm_isp_check_stream_cfg_cmd function processes stream configuration commands, it directly uses the num_streams value without verifying that it falls within acceptable bounds. This allows an attacker to specify an excessively large number of streams which then gets used to index into the stream_cfg_cmd->stream_handle array. The lack of bounds checking creates a classic buffer overflow scenario where memory beyond the allocated array boundaries can be accessed or modified.
This vulnerability impacts the integrity and stability of the Android kernel on Qualcomm devices, potentially allowing for privilege escalation or denial of service conditions. The flaw exists in the ISP (Image Signal Processor) subsystem which handles image and video streaming operations, making it particularly concerning for mobile devices where these operations are frequent. The vulnerability could be exploited through malicious applications or system-level attacks that send crafted stream configuration commands to the affected kernel functions.
The operational impact of CVE-2017-8251 extends beyond simple memory corruption, as it could enable attackers to execute arbitrary code with kernel privileges. This represents a significant security risk since the affected functions operate in kernel space, providing attackers with elevated access to the device's core systems. The vulnerability affects all Qualcomm products utilizing the Linux kernel through CAF, encompassing a wide range of mobile devices, tablets, and potentially other IoT devices that rely on Qualcomm chipsets.
Mitigation strategies for this vulnerability require immediate patching of the affected kernel versions and implementation of proper input validation within the msm_isp_check_stream_cfg_cmd and msm_isp_stats_update_cgc_override functions. The recommended approach involves adding bounds checking to ensure that stream_cfg_cmd->num_streams does not exceed the maximum array size before using it as an array index. This aligns with CWE-129 which addresses insufficient input validation and CWE-787 which covers out-of-bounds write conditions. Organizations should also implement runtime monitoring to detect anomalous stream configuration patterns that might indicate exploitation attempts.
Security practitioners should consider this vulnerability in their ATT&CK framework analysis, particularly focusing on privilege escalation techniques and kernel exploitation methods. The vulnerability's classification as a kernel-level buffer overflow places it within the realm of critical system compromise, requiring immediate attention in security assessment and patch management programs. Device manufacturers and carriers should prioritize rolling out security updates to affected devices, as this vulnerability could be leveraged for persistent access to mobile platforms and potentially lead to more sophisticated attacks targeting user data and device integrity.