CVE-2007-5634 in Speedfan
Summary
by MITRE
Speedfan.sys in Alfredo Milani Comparetti SpeedFan 4.33, when used on Microsoft Windows Vista x64, does not properly check a buffer during an IOCTL 0x9c402420 call, which allows local users to cause a denial of service (machine crash) and possibly gain privileges via unspecified vectors.
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Analysis
by VulDB Data Team • 09/10/2018
The vulnerability identified as CVE-2007-5634 affects SpeedFan.sys, a kernel-mode driver component of Alfredo Milani Comparetti SpeedFan version 4.33 specifically when deployed on Microsoft Windows Vista x64 operating systems. This driver serves as a hardware monitoring and control utility that interfaces directly with system hardware components including fans, temperature sensors, and voltage regulators. The flaw manifests within the driver's handling of IOCTL (Input/Output Control) operations, specifically targeting the 0x9c402420 command code which governs certain hardware control functions. The vulnerability represents a classic buffer overflow condition where the driver fails to perform adequate bounds checking on user-supplied data structures before processing them in kernel space. This failure creates a potential execution path where malicious input can overwrite adjacent memory locations, leading to unpredictable system behavior and potential privilege escalation opportunities.
The technical implementation of this vulnerability stems from improper validation of input parameters within the driver's IOCTL handling routine. When the SpeedFan.sys driver receives an IOCTL 0x9c402420 request, it processes user-supplied data without sufficient boundary verification, allowing attackers to craft specially formatted input that exceeds allocated buffer space. This condition creates a classic stack-based or heap-based buffer overflow depending on the specific memory layout and implementation details. The vulnerability's impact extends beyond simple denial of service as the compromised kernel memory access patterns could potentially enable privilege escalation attacks. According to CWE classification, this represents a buffer overflow vulnerability categorized under CWE-121, which deals with stack-based buffer overflow conditions in kernel-mode drivers. The Windows Vista x64 architecture further complicates exploitation due to its enhanced memory protection mechanisms including kernel address space layout randomization and data execution prevention features that may either mitigate or complicate exploitation attempts.
The operational impact of CVE-2007-5634 presents significant risks to system stability and security integrity within environments where SpeedFan is deployed. Local attackers with basic user privileges can leverage this vulnerability to either crash the entire system through denial of service conditions or potentially elevate their privileges to kernel level access. The combination of local execution requirements with the potential for privilege escalation creates a dangerous attack surface that could be exploited by malware or malicious insiders. The vulnerability's presence in a hardware monitoring driver is particularly concerning as these components often run with elevated privileges and maintain persistent access to critical system resources. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1068 which covers local privilege escalation through kernel exploits, and T1489 which addresses system shutdown/reboot attacks through denial of service conditions. The attack surface is further expanded by the fact that many enterprise environments rely on hardware monitoring tools like SpeedFan for system health monitoring, making this vulnerability particularly attractive to threat actors seeking persistent access to target systems.
Mitigation strategies for CVE-2007-5634 require immediate action to address the root cause through driver updates and system hardening measures. The primary remediation involves upgrading to a newer version of SpeedFan that properly implements input validation and buffer checking mechanisms for all IOCTL operations. System administrators should disable or uninstall the vulnerable SpeedFan driver from affected systems until proper updates are deployed. Additionally, implementing kernel-mode exploit protection measures such as Windows Driver Verifier, kernel patch protection, and enhanced monitoring for suspicious driver activity can help detect and prevent exploitation attempts. Network segmentation and privilege separation should be enforced to limit the potential impact of successful exploitation, while regular system auditing should monitor for unauthorized driver installations or modifications. The vulnerability highlights the critical importance of proper kernel-mode input validation and buffer management practices, emphasizing that drivers operating in kernel space must implement rigorous security controls to prevent exploitation of memory corruption vulnerabilities. Organizations should also consider implementing endpoint detection and response solutions that can identify anomalous behavior patterns consistent with driver-based attacks and buffer overflow exploitation attempts.