CVE-2018-6523 in AVS
Summary
by MITRE
In nProtect AVS V4.0 4.0.0.38, the driver file (TKFsAv.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 0x22045c.
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Analysis
by VulDB Data Team • 01/01/2020
The vulnerability identified as CVE-2018-6523 resides within the nProtect AVS V4.0 security software, specifically affecting version 4.0.0.38. This issue manifests through the kernel-mode driver component TKFsAv.SYS which handles various system-level operations. The flaw represents a critical security weakness that exposes the system to potential exploitation by local attackers who can manipulate the driver through improper input validation mechanisms. The vulnerability specifically targets the IOCTL (Input/Output Control) interface with code 0x22045c, which serves as the communication channel between user-mode applications and the kernel-mode driver component. This particular IOCTL implementation fails to properly validate incoming parameters, creating a pathway for malicious input that can disrupt normal system operations.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where a program reads data past the end of a valid buffer, and CWE-787, which covers out-of-bounds write operations that can corrupt memory. The driver's failure to validate input values from the specified IOCTL code creates a potential for arbitrary code execution or system instability. When local users submit malformed parameters to the TKFsAv.SYS driver through the 0x22045c interface, the system experiences unpredictable behavior that can manifest as blue screen of death (BSOD) conditions. This type of vulnerability falls under the ATT&CK framework's T1068, which covers 'Exploitation for Privilege Escalation' and T1059, covering 'Command and Scripting Interpreter' techniques that can be leveraged for system compromise.
The operational impact of this vulnerability extends beyond simple denial of service conditions as the unspecified other impacts could potentially include privilege escalation opportunities or system corruption that might allow attackers to execute malicious code with kernel-level privileges. Local users who can access the system and have the ability to interact with the nProtect AVS driver interface can exploit this weakness to disrupt system operations, potentially gaining elevated privileges or causing persistent system instability. The BSOD conditions can result in complete system downtime and data loss, while the unspecified impacts suggest the possibility of more sophisticated attacks that could compromise the integrity of the entire security stack. This vulnerability particularly affects systems where nProtect AVS is installed and running with kernel-level privileges, making it a significant concern for enterprise environments that rely on this particular antivirus solution.
Mitigation strategies for CVE-2018-6523 should focus on immediate patching of the nProtect AVS software to the latest version that addresses the input validation issues within the TKFsAv.SYS driver. Organizations should implement strict access controls to prevent unauthorized local users from interacting with the vulnerable driver interface, while monitoring for suspicious IOCTL activity through endpoint detection and response solutions. The vulnerability demonstrates the importance of proper input validation in kernel-mode drivers and highlights the need for comprehensive security testing of device drivers before deployment. System administrators should consider disabling unnecessary driver interfaces and implementing application whitelisting policies to prevent exploitation attempts. Additionally, regular security assessments of endpoint protection software should be conducted to identify similar validation flaws in other security components that could present similar risks to system integrity and availability.