CVE-2014-9796 in Android
Summary
by MITRE
app/aboot/aboot.c in the Qualcomm components in Android before 2016-07-05 on Nexus 5 and 7 (2013) devices does not validate the page size in the kernel header, which allows attackers to bypass intended access restrictions via a crafted boot image, aka Android internal bug 28820722 and Qualcomm internal bug CR684756.
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Analysis
by VulDB Data Team • 09/01/2022
The vulnerability identified as CVE-2014-9796 resides within the Qualcomm bootloader component known as aboot.c, which operates within the Android operating system framework on specific Nexus device models including the Nexus 5 and Nexus 7 (2013). This flaw represents a critical security oversight in the boot process validation mechanism that governs how kernel images are loaded and executed. The vulnerability stems from insufficient input validation within the bootloader's kernel header parsing functionality, specifically failing to properly verify the page size parameter that is crucial for memory management and access control during system initialization.
The technical exploitation of this vulnerability occurs through the manipulation of boot image parameters, particularly targeting the page size field within the kernel header structure. Attackers can craft a specially designed boot image that contains malformed page size values, which the bootloader accepts without proper validation. This validation failure enables unauthorized code execution during the boot process, effectively bypassing the intended access restrictions that should prevent arbitrary code loading. The flaw operates at the lowest level of system security, where the bootloader should act as the first line of defense against malicious code injection. According to CWE classification, this vulnerability maps to CWE-129 Input Validation and User-controlled Data, as the system fails to validate user-supplied kernel header parameters before processing them.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the integrity of the boot process and can lead to complete system compromise. An attacker with physical access to the device or the ability to install malicious boot images could potentially execute arbitrary code with kernel-level privileges, effectively bypassing all subsequent security mechanisms. This vulnerability directly relates to the ATT&CK technique T1068, which involves exploiting local privilege escalation vulnerabilities, and T1542, which covers exploitation of boot or logon initialization scripts. The attack surface is particularly concerning for mobile devices where physical access is often possible, and where the bootloader serves as a critical security boundary that should prevent unauthorized modifications to system firmware.
The vulnerability affects specific Nexus device models from 2013, making it particularly relevant to understanding the security landscape of older Android implementations. The targeted devices include the Nexus 5 and Nexus 7 (2013) models, which were widely distributed and may still be in use in various environments. The fact that this vulnerability was disclosed in 2016 with a patch date of July 2016 indicates that it remained unpatched for an extended period, highlighting potential gaps in the security update mechanisms for mobile devices. Organizations and users should understand that this vulnerability represents a persistent risk for legacy systems and underscores the importance of maintaining current security patches. The remediation approach requires proper validation of kernel header parameters within the bootloader component, ensuring that all page size values fall within acceptable ranges before proceeding with kernel execution. This vulnerability demonstrates the critical importance of secure bootloader implementation and the potential consequences of insufficient input validation in system-level components that operate with the highest privileges.