CVE-2017-18281 in Android
Summary
by MITRE
A bool variable in Video function, which gets typecasted to int before being read could result in an out of bound read access in all Android releases from CAF using the linux kernel
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Analysis
by VulDB Data Team • 06/03/2023
The vulnerability identified as CVE-2017-18281 represents a critical buffer overread condition affecting Android devices that utilize the Linux kernel from the Code Aurora Forum. This flaw exists within the video processing function where a boolean variable undergoes typecasting to an integer before being consumed by the system. The improper handling of this type conversion creates a scenario where memory access occurs beyond the intended boundaries of allocated buffers. The vulnerability affects all Android releases that incorporate kernel components from the Code Aurora Forum, indicating a widespread impact across multiple device models and manufacturers. This issue stems from inadequate input validation and memory management practices within the kernel-level video processing subsystem.
The technical implementation of this vulnerability involves a specific type conversion pattern that transforms a boolean value into an integer representation before the value is processed. When the boolean variable is cast to an integer, the resulting value may exceed the expected range of valid indices or offsets, leading to unauthorized memory access patterns. The out-of-bounds read occurs because the integer value derived from the boolean typecasting operation references memory locations beyond the allocated buffer boundaries. This type of vulnerability is classified under CWE-129 as an "Improper Validation of Array Index" and represents a classic case of integer overflow or underflow conditions. The flaw demonstrates poor defensive programming practices where type safety measures are insufficient to prevent memory corruption scenarios.
The operational impact of CVE-2017-18281 extends beyond simple memory access violations, as it creates potential attack vectors for privilege escalation and system compromise. An attacker could exploit this vulnerability to read sensitive kernel memory contents, potentially extracting confidential information or system credentials. The out-of-bounds read could also lead to system instability, causing unexpected crashes or denial of service conditions that disrupt normal device operation. Given that this vulnerability affects kernel-level components, successful exploitation could enable attackers to gain elevated privileges or execute arbitrary code within the kernel space. This vulnerability aligns with ATT&CK technique T1068 which describes "Exploitation for Privilege Escalation" and represents a critical pathway for attackers to move from user-level processes to kernel-level control.
Mitigation strategies for this vulnerability require immediate patching of affected Android kernel components from the Code Aurora Forum. Device manufacturers should prioritize updating their kernel implementations to address the improper typecasting logic within video processing functions. System administrators should implement monitoring solutions to detect anomalous memory access patterns that may indicate exploitation attempts. The fix should involve proper validation of integer values derived from boolean typecasting operations, ensuring that all indices remain within valid buffer boundaries. Additionally, developers should incorporate static analysis tools and code review processes that specifically target type conversion patterns to prevent similar issues in future implementations. Organizations should also consider implementing runtime protections such as stack canaries and memory address randomization to reduce the effectiveness of potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper type handling in kernel space programming and the need for comprehensive security testing of low-level system components.