CVE-2018-5085 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 0x83002124.
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Analysis
by VulDB Data Team • 12/19/2019
The vulnerability identified as CVE-2018-5085 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 0x83002124 which is used for communication between user-mode applications and the kernel-mode driver. The lack of proper validation creates an exploitable condition that can be leveraged by local attackers to manipulate the driver's behavior through crafted input parameters.
The technical nature of this vulnerability aligns with CWE-129, which describes "Improper Validation of Array Index" and CWE-755, which covers "Improper Handling of Exceptional Conditions." When a local user submits malformed input to the IOCTL 0x83002124 interface, the driver fails to validate the incoming data structures, leading to potential buffer overflows, memory corruption, or arbitrary code execution within kernel space. This type of vulnerability operates at the kernel level, making it particularly dangerous as it can bypass standard user-mode security controls and directly affect system stability and security.
The operational impact of this vulnerability manifests primarily through system instability and potential denial of service conditions that can result in blue screen of death (BSOD) errors. Local attackers with standard user privileges can exploit this flaw to crash the operating system, rendering the affected system unusable until reboot. Beyond simple denial of service, the vulnerability may enable more sophisticated attacks depending on the specific implementation details, potentially allowing privilege escalation or information disclosure. The attack vector is particularly concerning because it requires only local access, meaning that any user with login credentials can potentially exploit this vulnerability without requiring additional network connectivity or specialized attack tools.
Mitigation strategies for CVE-2018-5085 should focus on immediate patching of the K7 AntiVirus software to the latest version that addresses this input validation issue. System administrators should also implement monitoring for unusual IOCTL activity patterns and consider restricting local user privileges where possible. The vulnerability demonstrates the importance of proper kernel-mode input validation and aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation," as local users can leverage this flaw to gain elevated system privileges. Organizations should also conduct regular security assessments of third-party antivirus solutions to identify similar validation weaknesses in other security software components. The vulnerability serves as a reminder of the critical need for robust input validation in kernel-mode drivers, as these components operate with the highest system privileges and present the most significant attack surface when improperly secured.