CVE-2018-5086 in K7
Summary
by MITRE
In K7 AntiVirus 15.1.0306, the driver file (K7FWHlpr.sys) allows local users to cause a denial of service (BSOD) or possibly have unspecified other impact because of not validating input values from IOCtl 0x8300215F.
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Analysis
by VulDB Data Team • 12/19/2019
The vulnerability identified as CVE-2018-5086 resides within K7 AntiVirus version 15.1.0306, specifically within its kernel-mode driver component known as K7FWHlpr.sys. This driver operates at the privileged kernel level and handles various system operations through Windows I/O control codes, making it a critical component for the antivirus software's functionality. The flaw manifests when the driver processes IOCTL 0x8300215F, which is a specific control code used for communication between user-mode applications and the kernel-mode driver. The vulnerability stems from insufficient input validation mechanisms within the driver's handling of this particular IOCTL request.
The technical implementation of this vulnerability involves the driver's failure to properly validate input parameters received through the IOCTL 0x8300215F interface. When a local user or application sends malformed or unexpected input data to this IOCTL handler, the driver does not perform adequate bounds checking, type validation, or parameter sanitization. This lack of input validation creates a potential for arbitrary code execution or system instability. The vulnerability can result in a blue screen of death (BSOD) due to kernel memory corruption, or it may allow for unspecified other impacts that could potentially escalate privileges or cause system-wide disruptions. The driver's improper handling of unvalidated input values can lead to memory access violations, null pointer dereferences, or buffer overflows that compromise the operating system's stability and security.
From an operational perspective, this vulnerability represents a significant risk for local users who can exploit it to cause system crashes or potentially gain elevated privileges. The fact that it requires local system access means that an attacker would need to have user-level access to the system, which is often achievable through social engineering, phishing, or other initial compromise techniques. The impact extends beyond simple denial of service, as the unspecified other impacts could potentially allow for privilege escalation or persistent system compromise. The vulnerability affects the core security functionality of the antivirus software, creating a potential attack surface where malicious actors could leverage the driver's privileged execution context to undermine system security. This represents a classic case of a security boundary violation where legitimate system components become attack vectors.
Mitigation strategies for CVE-2018-5086 should focus on immediate patching of the affected K7 AntiVirus version, as vendors typically release security updates to address such kernel-mode vulnerabilities. System administrators should implement strict access controls and monitoring for kernel-mode driver interactions, particularly around IOCTL handling functions. The vulnerability aligns with CWE-129, which describes improper validation of input ranges, and may also relate to CWE-787, representing out-of-bounds write vulnerabilities. From an ATT&CK framework perspective, this vulnerability could be leveraged for privilege escalation techniques under the T1068, and potentially for system disruption through T1490. Organizations should also consider implementing kernel-mode driver monitoring, regular security assessments of antivirus components, and maintaining up-to-date threat intelligence regarding similar vulnerabilities in security software. Additionally, the use of least privilege principles and regular system audits can help limit the potential impact of such vulnerabilities.