CVE-2018-5956 in Zillya!
Summary
by MITRE
In Zillya! Antivirus 3.0.2230.0, the driver file (zef.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 0x9C402414.
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Analysis
by VulDB Data Team • 12/26/2019
The vulnerability identified as CVE-2018-5956 affects Zillya! Antivirus version 3.0.2230.0 and represents a critical security flaw within the antivirus driver component. This issue stems from inadequate input validation mechanisms within the zef.sys driver file, which is responsible for handling system-level operations and communications with the Windows kernel. The specific IOCTL (Input/Output Control) code 0x9C402414 serves as the attack vector where malicious input values can be submitted to trigger the vulnerability without proper sanitization or validation checks.
The technical exploitation of this vulnerability occurs through the driver's failure to validate input parameters received through the specified IOCTL interface. When local users submit crafted input data to the zef.sys driver via IOCTL 0x9C402414, the system lacks proper boundary checking, type validation, or input sanitization measures. This absence of validation creates a condition where malformed or unexpected input values can cause the Windows kernel to crash, resulting in a Blue Screen of Death (BSOD) or system instability. The vulnerability's classification as a local privilege escalation issue stems from the fact that any user with access to the system can potentially trigger this condition, making it particularly dangerous in multi-user environments where privilege separation is not properly enforced.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can potentially lead to system instability and unpredictable behavior. The BSOD condition represents a complete system crash that can result in data loss, service interruptions, and potential compromise of system integrity. In enterprise environments, this vulnerability could be exploited by malicious insiders or attackers who have already gained local access to a system, potentially using it as a stepping stone for further exploitation. The unspecified other impacts mentioned in the CVE description suggest that beyond the immediate BSOD condition, there may be additional security implications including privilege escalation opportunities or data corruption scenarios that could affect the overall security posture of affected systems.
This vulnerability aligns with CWE-129, which describes improper validation of input boundaries, and represents a classic example of insufficient input validation in kernel-mode drivers. The ATT&CK framework categorizes this issue under privilege escalation techniques, specifically targeting the use of kernel-mode vulnerabilities to gain elevated system privileges. From a mitigation perspective, the primary recommendation involves updating to a patched version of Zillya! Antivirus that properly validates all input values received through IOCTL interfaces. System administrators should also implement monitoring solutions to detect unusual IOCTL activity patterns and consider restricting local user privileges where possible. Additionally, the vulnerability highlights the importance of proper driver development practices including input validation, boundary checking, and secure coding methodologies that prevent similar issues from occurring in other antivirus and security software implementations.