An issue was discovered in VTS in Samsung Mobile Processor and Wearable Processor Exynos 1280, 2200, 1380, W920, W930, W1000. Improper input validation in the VTS driver leads to an arbitrary write.
Samsung Exynos processors are vulnerable to an arbitrary write due to improper input validation in the VTS driver. This allows attackers to potentially overwrite critical system memory, leading to remote code execution (RCE) and complete device compromise. This vulnerability impacts a wide range of Samsung mobile and wearable devices.
Step 1: Triggering the Vulnerability: The attacker crafts a malicious input, likely a specially formatted data packet or command, designed to be processed by the VTS driver. This input includes parameters such as a target memory address (offset) and data to be written.
Step 2: Input Delivery: The crafted input is sent to the VTS driver through a user-space application or a compromised application with access to the VTS driver.
Step 3: Driver Processing: The VTS driver receives the malicious input and attempts to process it. Due to the lack of proper input validation, the driver fails to verify the validity of the provided offset and data size.
Step 4: Memory Write: The driver proceeds to write the attacker-controlled data to the specified memory address. Because of the missing bounds check, the write operation can occur outside of the intended memory region.
Step 5: Code Execution (Potential): If the attacker successfully overwrites critical system data, such as a function pointer or a code segment, they can gain control of the device. This could lead to arbitrary code execution, allowing the attacker to install malware, steal data, or take complete control of the device.
The vulnerability stems from a flaw in the VTS (likely Video Test System or a similar driver) driver within Samsung's Exynos processors. The driver fails to properly validate input parameters provided by a user-space application. Specifically, the driver likely accepts a user-controlled offset and data to be written to a specific memory location. By providing a crafted input, an attacker can specify an arbitrary memory address and write arbitrary data to it. This leads to an arbitrary write primitive. The root cause is likely a missing or insufficient bounds check on the offset or data size, allowing the attacker to write outside of the intended memory region. The lack of proper input validation allows for the overwrite of critical system data, potentially including kernel code, leading to remote code execution (RCE). The vulnerability is exacerbated by the privileged nature of the VTS driver, which operates at a low level within the operating system.