CVE-2019-9451 in Android
Summary
by MITRE
In the Android kernel in the touchscreen driver there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-9451 resides within the Android kernel's touchscreen driver component, representing a critical security flaw that could enable local privilege escalation. This issue manifests as an out-of-bounds write condition that occurs due to the absence of proper bounds checking mechanisms within the kernel-level driver code. The vulnerability specifically affects the touchscreen input subsystem where the kernel fails to validate the boundaries of memory operations when processing touchscreen events or data structures. The missing validation allows malicious code executing with system privileges to potentially overwrite adjacent memory locations, creating opportunities for privilege escalation attacks.
The technical nature of this vulnerability aligns with CWE-787, which defines out-of-bounds write conditions as a common class of memory safety issues. The flaw operates at the kernel level where touchscreen driver code processes input events from hardware devices, making it particularly dangerous as it requires only system execution privileges to exploit. The absence of user interaction requirements for exploitation makes this vulnerability especially concerning from a threat perspective, as it can be leveraged without requiring physical access or user deception. Attackers can craft malicious input sequences or manipulate touchscreen data that triggers the vulnerable code path, leading to memory corruption that could be exploited to gain elevated privileges.
From an operational standpoint, this vulnerability represents a significant risk to Android devices as it provides a pathway for local attackers to escalate their privileges from regular system user to kernel-level execution. The exploitation process typically involves crafting specific touchscreen input patterns or data that will cause the driver to write beyond allocated memory boundaries. This memory corruption can potentially be leveraged to execute arbitrary code with kernel privileges, effectively compromising the entire system. The impact extends beyond simple privilege escalation as it can enable attackers to bypass security controls, modify system files, install malicious software, and potentially access sensitive data. The vulnerability affects all Android versions that incorporate the affected kernel touchscreen driver implementation, making it widespread across numerous device models and manufacturers.
The exploitation of CVE-2019-9451 aligns with several tactics outlined in the MITRE ATT&CK framework, particularly those related to privilege escalation and kernel exploitation. The vulnerability can be classified under the T1068 technique for bypassing user execution controls and T1059 for command and scripting interpreter usage. Security researchers have noted that the exploitation typically follows a pattern where attackers first gain system-level access through other means, then leverage this vulnerability to achieve kernel-level privileges. The attack surface is particularly broad as it affects any device running Android with the vulnerable touchscreen driver, including smartphones, tablets, and other touchscreen-enabled devices. Device manufacturers have addressed this vulnerability through kernel updates and security patches, but the widespread nature of affected devices means that many systems may still remain vulnerable.
Mitigation strategies for CVE-2019-9451 primarily focus on timely patching of the affected Android kernel components. Organizations and device users should ensure that their systems receive the latest security updates from manufacturers, which typically include fixes for the bounds checking issue in the touchscreen driver. Additionally, system administrators should implement monitoring solutions to detect anomalous touchscreen driver behavior or memory access patterns that might indicate exploitation attempts. The vulnerability highlights the importance of kernel security testing and input validation in embedded systems, as proper bounds checking should be implemented at all levels of system software to prevent such memory corruption issues. Network security teams should also consider the implications of this vulnerability when assessing overall system security posture, particularly in environments where Android devices are used as part of critical infrastructure components.