CVE-2017-17699 in K7
Summary
by MITRE
K7Sentry.sys 15.1.0.59 in K7 Antivirus 15.1.0309 has a NULL pointer dereference via a 0x950025ac DeviceIoControl request.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/15/2019
The vulnerability identified as CVE-2017-17699 represents a critical NULL pointer dereference flaw within the K7Sentry.sys kernel driver component of K7 Antivirus version 15.1.0.59. This issue manifests specifically through a DeviceIoControl request with the ioctl code 0x950025ac, which allows unprivileged user-mode processes to interact with the privileged kernel driver. The vulnerability stems from inadequate input validation within the driver's handling of device control requests, creating an exploitable condition where the driver attempts to dereference a null pointer when processing the malformed ioctl request.
The technical implementation of this vulnerability occurs at the kernel level where the K7Sentry.sys driver fails to properly validate the input parameters associated with the DeviceIoControl call. When a user-mode application sends the specific ioctl request with code 0x950025ac, the driver's control flow does not adequately check whether required pointers are properly initialized before attempting to access them. This fundamental flaw in defensive programming creates a path where the driver executes code that attempts to access memory at address zero, resulting in an immediate system crash or potential privilege escalation depending on the execution context and system configuration.
The operational impact of this vulnerability extends beyond simple system instability to encompass potential security implications for endpoint protection systems. Since K7 Antivirus operates with elevated privileges through its kernel driver components, a successful exploitation of this NULL pointer dereference could potentially allow attackers to achieve kernel-level code execution or cause denial of service conditions that would compromise the integrity of the antivirus protection mechanism. This creates a dangerous scenario where the very security tool designed to protect the system becomes a potential attack vector, undermining the trust model of the endpoint protection architecture.
From a cybersecurity perspective, this vulnerability aligns with CWE-476 which specifically addresses NULL pointer dereference conditions in software implementations. The flaw demonstrates poor input validation practices and inadequate error handling within kernel-mode drivers, which are critical components that require robust security controls. The ATT&CK framework categorizes this type of vulnerability under privilege escalation techniques where adversaries exploit kernel-level flaws to gain elevated system privileges. Organizations running affected K7 Antivirus versions face significant risk as this vulnerability could be leveraged by threat actors to bypass security controls or establish persistent access to compromised systems.
Mitigation strategies for this vulnerability should prioritize immediate patching of the K7 Antivirus software to the latest version that addresses the NULL pointer dereference issue. System administrators should also implement monitoring for unusual DeviceIoControl activity patterns that might indicate exploitation attempts, particularly targeting the specific ioctl code 0x950025ac. Additional protective measures include restricting user privileges to prevent unauthorized access to kernel drivers, implementing kernel-mode driver integrity checking, and maintaining comprehensive system logs to detect potential exploitation attempts. Organizations should also consider temporary disabling of the affected driver component until proper patches are deployed, though this approach may compromise endpoint protection capabilities during the remediation period.