CVE-2021-21790 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 information disclosure vulnerability identified as CVE-2021-21790 resides within the IOBit Advanced SystemCare Ultimate 14.2.0.220 driver implementation, representing a critical security flaw that undermines the fundamental principles of kernel-mode security. This vulnerability specifically manifests in the driver's handling of Privileged I/O read requests, where the system fails to properly validate or restrict access to sensitive kernel memory regions. The flaw enables attackers to craft malicious I/O request packets that exploit the driver's insufficient input validation mechanisms, creating a pathway for unauthorized data extraction from protected memory areas. The vulnerability's severity is amplified by its ability to leverage the IN instruction, which is designed to read data from I/O ports, but in this case becomes a vector for kernel memory disclosure through improper privilege enforcement.
The technical execution of this vulnerability follows a well-defined attack pattern that aligns with common kernel exploitation methodologies and maps directly to CWE-200, which addresses "Information Exposure," and CWE-264, covering "Permissions, Privileges, and Access Control." Attackers can construct specially crafted I/O request packets that trigger the driver's processing routine, allowing the IN instruction to read two bytes of data from specific I/O devices. This seemingly simple operation becomes dangerous when executed within the context of a privileged driver, as it can potentially expose sensitive kernel memory contents to unprivileged user-mode processes. The vulnerability demonstrates a classic privilege escalation vector where the driver's failure to properly enforce access controls creates an information leak that can reveal system internals, device configurations, or other sensitive data that should remain protected within kernel space.
The operational impact of CVE-2021-21790 extends far beyond simple information disclosure, as it creates a foundation for more sophisticated attacks within the ATT&CK framework's privilege escalation and defense evasion categories. The leaked information can include device register contents, memory addresses, or other sensitive kernel data that could be leveraged for further exploitation attempts. This vulnerability particularly affects systems running IOBit Advanced SystemCare Ultimate 14.2.0.220 where the driver is actively loaded and operational, potentially exposing critical system information to local users or attackers with minimal privileges. The attack surface is particularly concerning because it operates at the kernel level, where the privilege separation between user and kernel modes is typically most rigid, making such information leaks especially dangerous for system integrity and confidentiality.
Mitigation strategies for this vulnerability should focus on both immediate patching and broader system hardening measures. The primary recommendation involves applying the vendor-provided security update that addresses the driver's improper handling of I/O requests and implements proper privilege validation. Organizations should also consider implementing runtime monitoring solutions that can detect anomalous I/O request patterns or unauthorized access attempts to privileged system resources. Additionally, system administrators should ensure that only trusted software components are installed and that unnecessary drivers are disabled to minimize the attack surface. The vulnerability's classification as a kernel-mode information disclosure requires careful monitoring of system logs for unusual I/O activity, as well as maintaining current threat intelligence feeds that might indicate exploitation attempts targeting similar vulnerabilities in the broader software ecosystem.