CVE-2017-9725 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, during DMA allocation, due to wrong data type of size, allocation size gets truncated which makes allocation succeed when it should fail.
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Analysis
by VulDB Data Team • 12/29/2022
The vulnerability identified as CVE-2017-9725 represents a critical memory management flaw affecting Qualcomm Snapdragon processors integrated into numerous Android devices. This issue manifests within the Linux kernel implementation used by Qualcomm Android platforms, specifically impacting how direct memory access operations are handled during system initialization and runtime operations. The flaw exists in the kernel's memory allocation subsystem where improper data type handling leads to incorrect buffer sizing during DMA operations. According to CWE-190, this vulnerability stems from an integer overflow condition that occurs when the size parameter undergoes truncation, resulting in a situation where memory allocation appears successful despite exceeding intended limits.
The technical implementation of this vulnerability occurs during the Dynamic Memory Allocation process where the kernel attempts to reserve memory regions for DMA operations. When the allocation size parameter exceeds the maximum value that can be represented by its designated data type, the value becomes truncated or wrapped around, causing the allocation routine to proceed with an unexpectedly small size value. This truncation creates a scenario where the system allocates insufficient memory for the intended operation while simultaneously reporting success to the calling application or kernel module. The flaw is particularly dangerous because it operates silently, allowing malicious actors to exploit the truncated allocation to overwrite adjacent memory regions or manipulate kernel data structures. This vulnerability directly relates to the ATT&CK technique T1068 which describes the exploitation of legitimate credentials and system privileges to gain unauthorized access to system resources.
The operational impact of CVE-2017-9725 extends beyond simple memory corruption, as it creates potential pathways for privilege escalation and system compromise across all Qualcomm Snapdragon processors running affected Android versions. Attackers can leverage this vulnerability to manipulate kernel memory layouts, potentially enabling code execution in kernel space or bypassing security controls designed to protect system integrity. The vulnerability affects devices ranging from smartphones and tablets to automotive systems and IoT devices that utilize Qualcomm chipsets, making it particularly concerning for enterprise and industrial deployments. The flaw's presence in the Linux kernel's DMA subsystem means that legitimate system operations involving hardware communication, file I/O, and network operations could be compromised, creating opportunities for persistent backdoors or denial of service conditions. Furthermore, the vulnerability's exploitation can lead to complete system compromise as attackers may use the truncated allocation to overwrite critical kernel structures, potentially allowing for rootkit installation or complete system takeover.
Mitigation strategies for this vulnerability require both immediate patching and system hardening measures. Qualcomm released kernel updates addressing the specific integer truncation issue, requiring device manufacturers to update their Android firmware implementations. The recommended approach involves correcting the data type handling in the DMA allocation routines to ensure proper size validation and error reporting. System administrators should implement monitoring solutions to detect anomalous memory allocation patterns that could indicate exploitation attempts. Additionally, deploying kernel hardening measures such as stack canaries, memory protection barriers, and runtime integrity checks can help detect and prevent exploitation of this vulnerability. Organizations should also consider implementing device firmware verification mechanisms to ensure that all systems maintain patched kernel versions. The vulnerability's classification under CWE-190 and its potential for privilege escalation through ATT&CK technique T1068 underscores the importance of comprehensive security monitoring and immediate remediation across all affected platforms.