CVE-2018-5217 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 0x95002578.
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Analysis
by VulDB Data Team • 12/19/2019
The vulnerability identified as CVE-2018-5217 resides within the K7 Antivirus 15.1.0306 driver component known as K7Sentry.sys which operates at the kernel level to provide system protection. This flaw manifests through improper input validation mechanisms within the driver's handling of IOCTL (Input/Output Control) requests, specifically targeting the control code 0x95002578. The absence of adequate validation allows malicious or unintended input values to be processed without proper sanitization, creating a potential pathway for exploitation that can result in system instability and operational disruption.
The technical implementation of this vulnerability stems from the driver's failure to validate the parameters provided during IOCTL 0x95002578 requests, which represents a classic example of insufficient input validation as categorized under CWE-20. This weakness allows an attacker to craft malformed input data that, when processed by the vulnerable driver, can trigger unexpected behavior within the kernel space. The lack of proper bounds checking, parameter validation, or input sanitization creates a condition where arbitrary data can be passed to memory locations or system functions without proper verification, leading to unpredictable outcomes including system crashes.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as the described Blue Screen of Death (BSOD) represents a critical system failure that can render the affected machine unusable until reboot. Beyond the immediate DoS condition, the unspecified other impacts suggest potential for more severe consequences including privilege escalation or information disclosure, though the exact scope remains undetermined. The vulnerability affects local users, meaning that exploitation requires local system access but does not require network connectivity, making it particularly concerning for environments where local privilege escalation is possible or where untrusted users have access to systems running this antivirus software.
The exploitation of this vulnerability aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and T1490 which covers "Inhibit System Recovery". Attackers could leverage this weakness to cause persistent system instability or to gain elevated privileges through kernel-level manipulation. The vulnerability's presence in a security product itself creates a particularly dangerous scenario where an attacker could potentially compromise the very protection mechanisms meant to defend against attacks. Organizations should consider this vulnerability as part of broader security assessments, particularly in environments where multiple security products are installed, as the kernel-level nature of the flaw could potentially be chained with other vulnerabilities to achieve more significant impacts.
Mitigation strategies for CVE-2018-5217 should focus on immediate patching of the K7 Antivirus software to the latest version that addresses this validation issue. System administrators should also implement monitoring for unusual IOCTL activity patterns and consider disabling unnecessary driver functionality where possible. The vulnerability demonstrates the importance of proper kernel-mode input validation and highlights the need for comprehensive security testing of driver components. Organizations should also consider implementing additional endpoint protection measures to detect and prevent exploitation attempts, as the vulnerability represents a fundamental flaw in the driver's security architecture that cannot be fully mitigated through network-based controls alone.