CVE-2021-21791 in Advanced SystemCare Ultimate
Summary
by MITRE • 08/06/2021
An information disclosure vulnerability exists in the the way IOBit Advanced SystemCare Ultimate 14.2.0.220 driver handles Privileged I/O read requests. A specially crafted I/O request packet (IRP) can lead to privileged reads in the context of a driver which can result in sensitive information disclosure from the kernel. The IN instruction can read two bytes from the given I/O device, potentially leaking sensitive device data to unprivileged users.
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Analysis
by VulDB Data Team • 08/09/2021
The vulnerability described in CVE-2021-21791 represents a critical information disclosure flaw within the IOBit Advanced SystemCare Ultimate 14.2.0.220 driver implementation. This vulnerability stems from improper handling of privileged I/O read requests, creating a pathway for unauthorized information leakage from kernel space to user space. The flaw specifically manifests when the driver processes I/O request packets that contain privileged read operations, allowing malicious actors to exploit the system's I/O handling mechanisms. The vulnerability is particularly concerning because it operates at the kernel level where sensitive system data resides, making it a prime target for attackers seeking to extract confidential information from the operating system's core components.
The technical implementation of this vulnerability involves the driver's insufficient validation and sanitization of I/O request packets, particularly those containing privileged read operations. When the driver receives an IRP with specific parameters, it fails to properly enforce privilege checks before executing the IN instruction, which is designed to read data from I/O ports. This oversight allows the instruction to access two-byte data segments from I/O devices that should normally be restricted to privileged system processes only. The vulnerability specifically leverages the IN instruction's ability to read from hardware ports, enabling attackers to potentially extract sensitive device information that could include system configuration details, hardware identifiers, or other confidential data typically protected by kernel-level access controls. This flaw directly violates the fundamental security principle of privilege separation and creates an attack vector that bypasses normal kernel protection mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with potential pathways to escalate privileges and gain deeper system access. An attacker could potentially use the leaked information to identify system vulnerabilities, understand hardware configurations, or discover other security weaknesses within the system architecture. The ability to read kernel-level data through user-mode applications represents a significant compromise of system integrity and confidentiality. This vulnerability affects systems running IOBit Advanced SystemCare Ultimate 14.2.0.220 and could be exploited by local attackers with minimal privileges to gain access to sensitive system information that would normally be restricted to kernel-level processes. The attack vector is particularly dangerous because it operates through legitimate I/O handling mechanisms, making it difficult to detect through standard security monitoring approaches.
Security mitigation strategies for this vulnerability should focus on immediate driver updates and system patches provided by IOBit to address the privilege checking implementation. System administrators should ensure that all affected systems are updated to the latest version of Advanced SystemCare Ultimate that contains the patched driver components. Additionally, implementing runtime protection measures such as kernel patch protection and monitoring for suspicious I/O activity can help detect exploitation attempts. The vulnerability aligns with CWE-200 (Information Disclosure) and CWE-264 (Permissions, Privileges, and Access Controls) categories, representing a clear violation of information hiding principles in operating system design. From an ATT&CK framework perspective, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1068 (Exploitation for Privilege Escalation) techniques, as it enables attackers to extract information that can be used for further system compromise. Organizations should also consider implementing network-based monitoring to detect unusual I/O port access patterns and establish baseline behaviors for system drivers to identify potential exploitation attempts. The vulnerability underscores the importance of proper kernel-level privilege enforcement and highlights the need for comprehensive driver security testing to prevent similar issues in other system components.