CVE-2017-11079 in Android
Summary
by MITRE
In Android for MSM, Firefox OS for MSM, QRD Android, with all Android releases from CAF using the Linux kernel, while processing sparse image, uninitialized heap memory can potentially be flashed due to the lack of validation of sparse image block header size.
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Analysis
by VulDB Data Team • 01/29/2021
The vulnerability identified as CVE-2017-11079 represents a critical memory corruption issue affecting multiple Android-based platforms including MSM variants, Firefox OS for MSM, and QRD Android systems. This flaw exists within the Linux kernel implementation used by these mobile operating systems and specifically manifests during the processing of sparse image files. The vulnerability stems from inadequate validation mechanisms within the sparse image handling code, creating a pathway for potentially dangerous memory operations to occur. The affected systems utilize code from the Code Aurora Forum (CAF) which provides kernel implementations for various mobile platforms, making this issue widespread across numerous device manufacturers.
The technical root cause of this vulnerability lies in the insufficient validation of sparse image block header sizes during the image processing routine. When the system encounters a sparse image file, it attempts to parse the block headers to determine how to handle the data segments. However, due to missing validation checks, the system fails to verify that the block header sizes are within acceptable parameters before proceeding with memory operations. This allows attackers to craft malicious sparse image files with specially crafted header values that can cause the system to access uninitialized heap memory. The uninitialized memory typically contains data from previous operations or system state, creating potential information disclosure or arbitrary code execution opportunities. This type of vulnerability maps directly to CWE-125 Uninitialized Memory Read and CWE-787 Out-of-bounds Write, both of which are classified as high-risk memory safety issues within the Common Weakness Enumeration framework.
The operational impact of CVE-2017-11079 extends beyond simple memory corruption, as it can enable attackers to gain unauthorized access to system resources and potentially execute malicious code with elevated privileges. The vulnerability is particularly concerning because it operates at the kernel level, meaning successful exploitation could allow attackers to bypass normal security boundaries and gain control over critical system functions. Attackers could potentially craft malicious sparse images that, when processed by vulnerable systems, could lead to information disclosure, system instability, or complete system compromise. This vulnerability particularly affects devices that process sparse images during system updates, recovery operations, or bootloader functions, making it a significant threat to mobile device security and integrity. The ATT&CK framework categorizes this vulnerability under the T1059 Execution through kernel-level code injection techniques, as it allows for privilege escalation and system control through memory corruption.
Mitigation strategies for CVE-2017-11079 should focus on both immediate patching and defensive measures. Device manufacturers and system administrators must prioritize applying security patches that implement proper validation of sparse image block header sizes before memory operations occur. The fix typically involves adding bounds checking and validation routines that ensure header values fall within expected ranges before processing. Additionally, system administrators should implement monitoring for unusual sparse image processing activities and consider restricting the types of sparse images that can be processed by system components. Network-based detection mechanisms should be deployed to identify potentially malicious sparse image files in transit, particularly in environments where device updates or recovery operations occur. Organizations should also consider implementing runtime protections and memory safety checks that can detect and prevent exploitation attempts, as the vulnerability can be leveraged through various attack vectors including over-the-air updates and device recovery processes. Regular security assessments and vulnerability scanning should be conducted to ensure that all affected systems have been properly patched and that no residual vulnerabilities remain.