CVE-2018-5088 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 0x8300211C.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/19/2019
The vulnerability identified as CVE-2018-5088 resides within the K7 AntiVirus 15.1.0306 software suite, specifically targeting the 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 in the security architecture. The flaw manifests when the driver fails to properly validate input parameters received through IOCTL 0x8300211C, creating a potential attack surface that could be exploited by local malicious actors. The vulnerability represents a classic case of inadequate input validation that can lead to system instability and potential privilege escalation scenarios.
The technical implementation of this vulnerability stems from the driver's lack of proper parameter validation for the specified IOCTL code. When a local user submits crafted input data to the driver through this particular I/O control interface, the system does not perform sufficient sanitization or bounds checking on the received parameters. This absence of validation allows malicious input to traverse the driver's execution path without proper safeguards, potentially causing the kernel to execute unintended operations or access invalid memory locations. The vulnerability classifies under CWE-129 Input Validation and Output Processing, specifically addressing the weakness where insufficient validation of input parameters leads to system instability.
The operational impact of this vulnerability extends beyond simple denial of service conditions, though the primary reported effect is a Blue Screen of Death (BSOD) that renders the system unstable and unusable. Local users with standard privileges can exploit this weakness to crash the operating system, effectively creating a denial of service condition that disrupts normal system operations and potentially causing data loss. However, the description mentions "possibly have unspecified other impact," suggesting that the vulnerability might also enable more sophisticated attacks such as privilege escalation or information disclosure. The kernel-level nature of the driver means that exploitation could potentially allow attackers to gain elevated privileges or access protected system resources, though the exact scope of these additional impacts requires further analysis.
Mitigation strategies for CVE-2018-5088 should focus on both immediate remediation and long-term security hardening measures. The most effective immediate solution involves updating to the latest version of K7 AntiVirus software where the driver validation has been properly implemented and the vulnerability has been patched. System administrators should also consider implementing additional security controls such as disabling unnecessary kernel drivers, applying the principle of least privilege, and monitoring for suspicious I/O control operations. From a defensive perspective, this vulnerability aligns with ATT&CK technique T1068, which covers local privilege escalation, and T1490, which addresses exploitation of remote services. Organizations should also implement proper input validation controls at the kernel level and consider using exploit protection mechanisms such as control flow integrity and address space layout randomization to reduce the effectiveness of potential exploitation attempts. The vulnerability demonstrates the critical importance of proper kernel-mode input validation and highlights the need for comprehensive security testing of privileged system components.