CVE-2014-9878 in Android
Summary
by MITRE
drivers/mmc/card/mmc_block_test.c in the Qualcomm components in Android before 2016-08-05 on Nexus 5 devices does not reject kernel-space buffer addresses, which allows attackers to gain privileges via a crafted application, aka Android internal bug 28769208 and Qualcomm internal bug CR547479.
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Analysis
by VulDB Data Team • 09/12/2022
The vulnerability identified as CVE-2014-9878 represents a critical privilege escalation flaw within the Android operating system's kernel-level storage subsystem. This issue specifically affects Qualcomm-based components in Android versions prior to 2016-08-05, particularly impacting Nexus 5 devices. The vulnerability stems from insufficient validation mechanisms within the mmc_block_test.c driver component that handles MMC (MultiMediaCard) block operations. The flaw allows malicious applications to manipulate kernel-space buffer addresses, bypassing normal security boundaries that should prevent user-space applications from directly accessing or manipulating kernel memory regions.
The technical implementation of this vulnerability exploits a fundamental weakness in kernel memory management where the mmc_block_test.c driver fails to properly validate buffer addresses supplied by user-space applications. When a crafted application attempts to perform MMC block operations, it can supply kernel memory addresses as buffer parameters, effectively creating a situation where user-space code can manipulate kernel data structures. This type of vulnerability falls under the CWE-787 category of "Out-of-bounds Write" and aligns with ATT&CK technique T1068 which describes "Local Privilege Escalation" through kernel exploits. The vulnerability specifically targets the kernel's memory management subsystem where proper address validation should prevent user-space applications from accessing kernel memory directly.
The operational impact of this vulnerability is severe as it enables a malicious application to achieve full system compromise without requiring any special privileges or user interaction beyond installation. Once exploited, the attacker gains kernel-level privileges, allowing complete control over the device including the ability to read or modify any system file, install persistent backdoors, access encrypted data, and bypass all security mechanisms. This represents a classic privilege escalation attack that transforms a standard application sandbox into a full system compromise, as the attacker can manipulate kernel data structures and potentially escalate to root access. The vulnerability affects the core storage subsystem and can be exploited to gain access to sensitive user data, system configuration, and device credentials.
Mitigation strategies for this vulnerability require immediate patching of the affected Android versions and implementation of proper kernel memory validation controls. System administrators should ensure that all Nexus 5 devices are updated to Android versions released after 2016-08-05, which contain the necessary security patches. Additionally, organizations should implement monitoring for suspicious buffer operations and kernel memory access patterns that could indicate exploitation attempts. The fix typically involves implementing stricter validation of buffer addresses within the mmc_block_test.c driver, ensuring that user-space applications cannot supply kernel memory addresses as parameters. This aligns with the principle of least privilege and proper kernel boundary enforcement as recommended by security frameworks. Regular security audits of kernel components and implementation of kernel address space layout randomization (KASLR) can further reduce the risk of exploitation, while maintaining proper access controls and memory validation mechanisms prevents similar vulnerabilities from emerging in the future.