CVE-2018-15738 in AntiMalware
Summary
by MITRE
An issue was discovered in STOPzilla AntiMalware 6.5.2.59. The driver file szkg64.sys contains an Arbitrary Write vulnerability due to not validating the output buffer address value from IOCtl 0x8000205F.
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Analysis
by VulDB Data Team • 10/18/2023
The vulnerability identified as CVE-2018-15738 represents a critical security flaw within STOPzilla AntiMalware version 6.5.2.59 that exposes the system to potential privilege escalation attacks through improper input validation mechanisms. This issue resides within the kernel-mode driver component szkg64.sys which handles device control operations through the Windows I/O control interface. The specific vulnerability manifests when the driver processes IOCTL code 0x8000205F without adequately validating the user-supplied output buffer address, creating an arbitrary write condition that can be exploited by malicious actors to write data to arbitrary memory locations within the kernel space.
The technical implementation of this vulnerability falls under the category of improper input validation and memory corruption as classified by CWE-121, where the driver fails to validate the address space of user-provided buffer parameters. When a user-mode application invokes the vulnerable IOCTL function, the driver accepts the output buffer address directly without performing proper bounds checking or address validation against kernel memory regions. This allows an attacker to specify any memory address within the system's virtual address space, enabling them to overwrite critical kernel data structures, function pointers, or other sensitive memory locations. The flaw essentially provides an attacker with a mechanism to perform arbitrary memory writes with kernel-level privileges, effectively bypassing standard operating system security boundaries and access controls.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and complete control over the affected machine. Attackers can leverage this arbitrary write capability to modify the kernel's memory layout, inject malicious code into kernel space, or manipulate critical system components such as the process scheduler, memory manager, or security subsystems. The vulnerability affects systems running STOPzilla AntiMalware 6.5.2.59 and potentially other versions with similar driver implementations, creating a persistent threat vector that can be exploited by both local and remote attackers depending on the system configuration and access permissions. This type of vulnerability directly aligns with ATT&CK technique T1068 which describes privilege escalation through kernel exploits and T1059 which covers execution through system commands or scripts that can be leveraged once kernel access is obtained.
Mitigation strategies for CVE-2018-15738 require immediate action from system administrators and security teams to address the root cause through proper driver patching and system hardening measures. The most effective immediate solution involves updating STOPzilla AntiMalware to a version that properly validates IOCTL buffer addresses and implements proper input validation mechanisms for kernel-mode drivers. Organizations should also implement runtime protection measures such as kernel address space layout randomization kASLR, data execution prevention DEP, and driver signature enforcement to limit the effectiveness of potential exploitation attempts. Additional defensive measures include monitoring for suspicious IOCTL activity patterns, implementing strict access controls for driver interfaces, and conducting thorough vulnerability assessments of all installed security software to identify similar issues in other anti-malware or system protection drivers. System administrators should also consider implementing network-based intrusion detection systems to monitor for exploitation attempts targeting known kernel-mode vulnerabilities and establish comprehensive incident response procedures to address potential compromise scenarios.