CVE-2018-5218 in K7
Summary
by MITRE
In K7 Antivirus 15.1.0306, the driver file (K7Sentry.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 0x950025b0.
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Analysis
by VulDB Data Team • 12/19/2019
The vulnerability identified as CVE-2018-5218 resides within the K7 Antivirus 15.1.0306 driver component known as K7Sentry.sys which operates at the kernel level of the Windows operating system. This driver exposes a critical security flaw through its handling of input validation for a specific IOCTL (Input/Output Control) command identified by the code 0x950025b0. The vulnerability represents a classic example of insufficient input validation that can be exploited by local malicious users to compromise system stability and potentially execute arbitrary code. The driver operates with elevated privileges due to its kernel-mode execution context, making it a prime target for privilege escalation attacks and system compromise attempts.
The technical root cause of this vulnerability stems from the driver's failure to properly validate input parameters received through the IOCTL interface. When a local user crafts a malicious IOCTL request with malformed or unexpected input values to the 0x950025b0 command, the driver processes these inputs without adequate sanitization or verification mechanisms. This lack of input validation creates a condition where the driver's internal processing logic can encounter unexpected data structures or values that lead to memory corruption. The vulnerability manifests as a Blue Screen of Death (BSOD) due to kernel-mode memory corruption, but may also potentially allow for more sophisticated attacks including privilege escalation or arbitrary code execution depending on the specific nature of the input manipulation.
The operational impact of this vulnerability extends beyond simple denial of service conditions as it represents a fundamental security flaw that can be exploited by any local user with access to the system. The BSOD condition effectively renders the system unusable until a reboot occurs, creating significant availability issues for end users and organizations. However, the potential for more severe consequences exists since the driver operates in kernel space with high privileges, potentially allowing attackers to escalate their privileges and gain unauthorized access to system resources. This vulnerability directly maps to CWE-129, which describes improper validation of input boundaries, and also aligns with ATT&CK technique T1068, which covers exploit for privilege escalation.
Mitigation strategies for CVE-2018-5218 should focus on immediate remediation through official vendor patches and updates. Organizations should prioritize updating to the latest version of K7 Antivirus that addresses this specific vulnerability in the K7Sentry.sys driver. System administrators should also implement additional monitoring and logging of IOCTL activity related to kernel drivers to detect potential exploitation attempts. The vulnerability highlights the importance of kernel-mode driver security and proper input validation practices as outlined in the OWASP Top 10 for kernel-level vulnerabilities. Organizations should consider implementing additional security controls such as driver signature enforcement and system integrity monitoring to prevent exploitation of similar vulnerabilities in other security software components. Regular security assessments of kernel-mode drivers and proactive vulnerability management should be implemented to prevent similar issues from occurring in the future.