CVE-2017-15303 in CPU-Z
Summary
by MITRE
In CPUID CPU-Z before 1.43, there is an arbitrary memory write that results directly in elevation of privileges, because any program running on the local machine (while CPU-Z is running) can issue an ioctl 0x9C402430 call to the kernel-mode driver (e.g., cpuz141_x64.sys for version 1.41).
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Analysis
by VulDB Data Team • 11/24/2019
The vulnerability identified as CVE-2017-15303 represents a critical privilege escalation flaw in CPUID CPU-Z version 1.42 and earlier, where the software fails to properly validate input parameters when communicating with its kernel-mode driver component. This security weakness stems from the absence of proper access controls and input sanitization within the driver interface, specifically in the ioctl handling mechanism that processes user-space requests. The vulnerability exists because the kernel-mode driver cpuz141_x64.sys accepts arbitrary memory write operations through the ioctl command 0x9C402430 without sufficient validation of the parameters provided by user-space applications. This design flaw allows any locally running program to potentially manipulate memory locations within the kernel space, effectively bypassing normal operating system security boundaries.
The technical exploitation of this vulnerability occurs through the manipulation of the ioctl interface exposed by the CPU-Z kernel driver, which operates at a privilege level that exceeds that of regular user applications. When a malicious program executes the ioctl call with crafted parameters, it can directly write data to arbitrary memory addresses within the kernel address space, enabling attackers to modify critical system structures such as process control blocks, memory management tables, or even kernel function pointers. This arbitrary memory write capability directly violates the fundamental security principle that user-space applications should not be able to directly manipulate kernel memory, creating a direct path for privilege escalation from user level to kernel level execution. The vulnerability is classified under CWE-787 as an out-of-bounds write, specifically an improper restriction of operations within the bounds of a memory buffer, while also aligning with CWE-264 as a privilege escalation through improper access control.
The operational impact of this vulnerability extends far beyond simple local privilege escalation, as it provides attackers with the ability to execute arbitrary code with kernel-level privileges, potentially leading to complete system compromise. An attacker with local access to a machine running vulnerable CPU-Z versions can leverage this flaw to gain root or administrator access, allowing them to install persistent backdoors, modify system files, disable security features, or extract sensitive information from the kernel memory space. The vulnerability is particularly dangerous because it requires no special privileges to exploit, making it accessible to any user on the local system who can run arbitrary programs. This makes it a prime target for malware authors and attackers who seek to establish persistent access to systems, as the attack surface is broad and the exploitation vector is straightforward. The attack pattern aligns with ATT&CK technique T1068 which involves local privilege escalation through kernel exploits, and T1543 which covers persistence mechanisms that can be established through kernel-level modifications.
Mitigation strategies for this vulnerability primarily involve immediate remediation through software updates, as CPUID released version 1.43 and later that addressed the improper validation of ioctl parameters within the kernel driver. System administrators should ensure all instances of CPU-Z are updated to versions 1.43 or later, which implement proper input validation and access control mechanisms for the kernel driver interface. Additionally, organizations should consider implementing application whitelisting policies to prevent unauthorized execution of potentially malicious programs that could exploit this vulnerability. The kernel driver should be configured with appropriate access controls and the ioctl interface should be properly validated to prevent arbitrary memory writes. Security monitoring should include detection of unusual ioctl activity related to the CPU-Z driver, and system integrity checks should verify that the kernel driver has not been tampered with or replaced by malicious versions. In environments where CPU-Z is not essential, the software should be uninstalled to eliminate the attack surface entirely, as the vulnerability cannot be patched without removing the problematic driver component.