CVE-2015-9215 in Android
Summary
by MITRE
In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Mobile MDM9615, MDM9625, MDM9635M, and SD 810, improper input validation can cause a null pointer dereference in USB bootloader find_ep() function.
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Analysis
by VulDB Data Team • 01/26/2020
The vulnerability identified as CVE-2015-9215 represents a critical null pointer dereference flaw within the USB bootloader component of Qualcomm Snapdragon mobile chipsets. This issue affects Android devices released prior to the 2018-04-05 security patch level and specifically impacts the MDM9615, MDM9625, MDM9635M, and SD 810 processor variants. The flaw resides in the find_ep() function of the USB bootloader, which fails to properly validate input parameters before attempting to dereference pointers, creating a potential exploitation vector for malicious actors.
The technical nature of this vulnerability stems from inadequate input validation mechanisms within the USB bootloader's find_ep() function. When the bootloader processes USB endpoint configuration data, it does not sufficiently validate the incoming parameters, allowing malformed or unexpected input to cause the function to attempt dereferencing a null pointer. This condition occurs during the USB device enumeration process when the system attempts to locate specific USB endpoints, leading to a system crash or potential privilege escalation depending on the execution context. The vulnerability aligns with CWE-476 which specifically addresses null pointer dereference conditions, and represents a classic example of improper input validation leading to memory corruption.
The operational impact of this vulnerability extends beyond simple system instability, as it could potentially enable attackers to gain unauthorized access to device functionality or execute arbitrary code within the bootloader environment. Since the USB bootloader operates at a privileged level and handles USB device initialization before the main operating system loads, exploitation could allow adversaries to bypass security mechanisms, modify device firmware, or establish persistent access points. This vulnerability particularly affects devices that rely on Qualcomm's secure boot processes and USB communication protocols, making it a significant concern for mobile device security. The issue demonstrates how low-level bootloader components can serve as critical attack surfaces that compromise the entire device security architecture.
Mitigation strategies for CVE-2015-9215 primarily focus on applying the relevant security patches released by Qualcomm and device manufacturers. Users should ensure their devices receive the 2018-04-05 security update or later, which includes fixes for the USB bootloader input validation issues. Device manufacturers should implement robust input validation checks within bootloader components and conduct thorough security testing of USB communication protocols. Additionally, security researchers and device manufacturers should consider implementing runtime protections such as pointer validation checks and memory access controls to prevent exploitation of similar vulnerabilities. The vulnerability highlights the importance of securing bootloader components as outlined in the ATT&CK framework's bootkit and rootkit categories, where early-stage system compromise can lead to complete device takeover. Organizations should also consider implementing USB device access controls and monitoring for unusual USB enumeration patterns that might indicate exploitation attempts.