CVE-2018-5219 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 0x83002168.
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Analysis
by VulDB Data Team • 12/19/2019
The vulnerability identified as CVE-2018-5219 affects K7 Antivirus version 15.1.0306 and represents a critical security flaw within the kernel-mode driver component K7FWHlpr.sys. This issue stems from inadequate input validation mechanisms within the driver's implementation, specifically concerning IOCTL (Input/Output Control) command 0x83002168. The vulnerability exists at the intersection of kernel-level security and improper privilege handling, creating a pathway for local attackers to exploit the system's defensive mechanisms. The driver's failure to validate input parameters before processing them creates a condition where maliciously crafted input can trigger unexpected behavior within the operating system kernel.
The technical nature of this vulnerability aligns with CWE-129, which describes improper validation of input buffers, and CWE-787, which addresses out-of-bounds write conditions. When a local user submits specially crafted input to the IOCTL 0x83002168 command, the driver processes this data without proper bounds checking or parameter validation. This lack of input sanitization allows the attacker to potentially manipulate kernel memory structures or trigger invalid memory access patterns that result in system instability. The vulnerability's impact extends beyond simple denial of service, as the unspecified other impacts could include privilege escalation opportunities or arbitrary code execution within kernel space. The BSOD (Blue Screen of Death) occurrence represents the most immediate and visible manifestation of this flaw, where the kernel terminates due to critical memory corruption or invalid instruction execution.
The operational impact of CVE-2018-5219 is significant for any system running the affected K7 Antivirus version, as local users who can execute code with sufficient privileges can leverage this vulnerability to disrupt system operations. The attack vector requires local access but does not necessitate elevated privileges beyond what a standard user might already possess, making it particularly dangerous in multi-user environments where privilege separation is not properly enforced. This vulnerability demonstrates poor adherence to secure coding practices and represents a failure in the principle of least privilege within the driver's design. The potential for unspecified other impacts suggests that attackers might be able to exploit this condition to gain additional system access or manipulate security controls beyond simple service disruption.
Mitigation strategies for this vulnerability should focus on immediate patching of the K7 Antivirus software to version 15.1.0307 or later, which contains the necessary input validation fixes. System administrators should also implement monitoring for unusual IOCTL activity patterns and consider disabling unnecessary driver functionality until the patch is applied. From an ATT&CK framework perspective, this vulnerability could be categorized under T1068 for local privilege escalation and T1490 for denial of service attacks. Organizations should conduct vulnerability assessments to identify systems running the affected software and implement layered security controls including endpoint detection and response solutions to monitor for exploitation attempts. The vulnerability also highlights the importance of kernel-mode driver security testing and proper input validation implementation in security software to prevent attackers from leveraging legitimate system components against the very systems they are designed to protect.