CVE-2021-28686 in GPUTweak II
Summary
by MITRE • 04/08/2021
AsIO2_64.sys and AsIO2_32.sys in ASUS GPUTweak II before 2.3.0.3 allow low-privileged users to trigger a stack-based buffer overflow. This could enable low-privileged users to achieve Denial of Service via a DeviceIoControl.
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Analysis
by VulDB Data Team • 04/15/2021
The vulnerability identified as CVE-2021-28686 affects the ASUS GPUTweak II software utility, specifically targeting the kernel-mode drivers AsIO2_64.sys and AsIO2_32.sys. This issue represents a critical security flaw that undermines the integrity of the system's privilege separation mechanisms. The vulnerability resides within the device driver component responsible for managing GPU-related functionalities through the Windows kernel's device I/O control interface. The flaw manifests as a stack-based buffer overflow that occurs when processing input data through DeviceIoControl calls, creating a pathway for privilege escalation and system instability.
The technical implementation of this vulnerability stems from inadequate input validation within the driver's handling of user-supplied data. When low-privileged users execute DeviceIoControl operations against the vulnerable driver interfaces, the system fails to properly bounds-check incoming parameters before copying them into fixed-size stack buffers. This classic buffer overflow condition allows attackers to overwrite adjacent stack memory, potentially corrupting the program's execution flow. The vulnerability is particularly concerning because it operates at the kernel level where privilege distinctions between user and system modes become irrelevant, making it possible for unprivileged users to execute arbitrary code or cause system crashes.
From an operational perspective, this vulnerability creates significant risk for systems running ASUS GPUTweak II software versions prior to 2.3.0.3. The Denial of Service attack vector represents a direct threat to system availability, as malicious actors can repeatedly trigger the buffer overflow condition to crash the targeted system. The impact extends beyond simple service disruption, as the vulnerability could potentially be exploited for privilege escalation attacks, allowing attackers to gain elevated system privileges. The attack surface is particularly broad since the vulnerability affects both 32-bit and 64-bit system architectures, increasing the potential target pool. According to CWE classification, this represents a CWE-121 stack-based buffer overflow vulnerability, which falls under the broader category of memory safety issues that have historically been primary attack vectors for system compromise.
The security implications of CVE-2021-28686 align with ATT&CK techniques related to privilege escalation and defense evasion. The vulnerability enables adversaries to leverage existing legitimate system interfaces to achieve unauthorized system access, making detection more challenging. The attack requires minimal privileges to initiate, which means that even standard user accounts can potentially exploit this flaw. Mitigation strategies should prioritize immediate software updates to version 2.3.0.3 or later, which contain patches addressing the buffer overflow conditions. Additionally, system administrators should consider implementing driver signature enforcement policies and monitoring for unusual DeviceIoControl activity. The vulnerability demonstrates the critical importance of proper input validation in kernel-mode components, as inadequate bounds checking in device drivers can provide attackers with direct pathways to system compromise. Organizations should also consider implementing network segmentation and access controls to limit potential exploitation opportunities while awaiting patch deployment.