CVE-2019-9453 in Android
Summary
by MITRE
In the Android kernel in F2FS touch driver there is a possible out of bounds read due to improper input validation. This could lead to local information disclosure with system execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-9453 resides within the Android kernel's F2FS (Flash-Friendly File System) touch driver implementation, representing a critical security flaw that undermines system integrity. This issue manifests as a potential out of bounds read condition that arises from inadequate input validation mechanisms within the kernel subsystem responsible for touch input processing. The F2FS touch driver operates at the kernel level, processing input events from touchscreen hardware and translating them into system-level interactions that applications can utilize. When malformed or unexpected input data reaches this driver component, the absence of proper bounds checking allows the system to attempt reading memory locations beyond the intended buffer boundaries.
The technical exploitation of this vulnerability occurs through a specific flaw in how the touch driver handles input validation for touch coordinates and event data. When processing touch events, the driver fails to properly validate the size and structure of incoming data packets, particularly those containing coordinate information and touch pressure measurements. This validation gap creates an opportunity for attackers to craft malicious input sequences that cause the driver to read beyond allocated memory regions. The out of bounds read vulnerability is classified under CWE-129, which specifically addresses insufficient input validation, and can be mapped to ATT&CK technique T1068 under the category of Exploitation for Privilege Escalation. The vulnerability requires system execution privileges to exploit, indicating that the attacker must already possess elevated access rights within the system to leverage this flaw effectively.
The operational impact of CVE-2019-9453 extends beyond simple information disclosure, as it provides attackers with the ability to extract sensitive data from kernel memory spaces. This information disclosure can potentially reveal kernel memory addresses, configuration data, cryptographic keys, or other system-sensitive information that could be used to further compromise the device. The fact that no user interaction is required for exploitation means that an attacker with system-level privileges can automatically trigger this vulnerability, making it particularly dangerous in environments where such privileges might be compromised. The implications are severe because kernel-level information disclosure can enable attackers to bypass security mechanisms, understand system memory layout, and potentially facilitate more sophisticated attacks such as kernel exploitation or privilege escalation. The vulnerability affects Android devices running kernel versions that include the F2FS touch driver implementation, making it relevant to a significant portion of mobile devices that utilize this file system for storage management.
Mitigation strategies for CVE-2019-9453 primarily involve applying security patches provided by device manufacturers and Google, which typically include enhanced input validation routines and bounds checking mechanisms within the F2FS touch driver. Organizations should prioritize updating their Android devices to versions that contain the patched kernel components, particularly focusing on the F2FS file system driver modifications. System administrators should implement monitoring solutions that can detect anomalous input processing patterns from touch drivers, as these may indicate attempted exploitation of the vulnerability. Additionally, security teams should consider implementing runtime protections such as kernel address space layout randomization and stack canaries that can help mitigate the impact of memory corruption vulnerabilities. The vulnerability highlights the importance of proper input validation in kernel drivers and serves as a reminder that even seemingly benign components like touch input handlers can contain critical security flaws. Device manufacturers should adopt more rigorous security testing procedures for kernel components, particularly those handling user input, to prevent similar issues from emerging in future releases.