CVE-2018-20331 in AVL ATool
Summary
by MITRE
Local attackers can trigger a Kernel Pool Buffer Overflow in Antiy AVL ATool v1.0.0.22. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the processing of IOCTL 0x80002004 by the ssdt.sys kernel driver. The bug is caused by failure to properly validate the length of the user-supplied data. An attacker can leverage this vulnerability to execute arbitrary code in the context of the kernel, which could lead to privilege escalation. A failed exploit could lead to denial of service.
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Analysis
by VulDB Data Team • 06/20/2023
This vulnerability represents a critical kernel-level buffer overflow in the Antiy AVL ATool security software version 1.0.0.22, specifically affecting the ssdt.sys kernel driver component. The flaw manifests when processing IOCTL command 0x80002004, which is a device control interface used for communication between user-space applications and kernel drivers. The vulnerability stems from inadequate input validation within the driver's handling of user-supplied data structures, creating a classic pool buffer overflow condition where maliciously crafted input can overwrite adjacent memory regions in the kernel's memory pool. This type of vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios, though the specific implementation in this case involves kernel pool memory management. The vulnerability exists in the context of a legitimate security tool that should be protecting systems, making it particularly concerning as it provides a potential attack vector through the very software designed to defend against threats.
The operational impact of this vulnerability extends far beyond simple denial of service conditions, as it enables full privilege escalation from user-level to kernel-level execution. An attacker who successfully exploits this vulnerability gains complete control over the target system, with the ability to execute arbitrary code with the highest system privileges. This privilege escalation capability aligns with ATT&CK technique T1068, which covers 'Local Privilege Escalation' through kernel exploits, and specifically demonstrates how legitimate system components can be weaponized for malicious purposes. The exploit requires initial access through low-privileged code execution, which could occur through social engineering, phishing, or other initial compromise vectors, but once achieved, the attacker can leverage the kernel-level access to install persistent backdoors, exfiltrate sensitive data, or completely compromise the system. The vulnerability's presence in security software creates a particularly dangerous scenario where the attack surface is expanded through legitimate system components.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security posture improvements. The most effective immediate solution involves updating to a patched version of Antiy AVL ATool that properly validates input lengths and implements proper bounds checking for all user-supplied data. System administrators should also implement runtime protection measures such as kernel patch protection, driver signature enforcement, and application whitelisting to prevent exploitation attempts. From a defensive perspective, monitoring for suspicious IOCTL activity and implementing security controls like Windows Defender Application Control or similar technologies can help detect and prevent exploitation attempts. The vulnerability highlights the importance of secure coding practices in kernel drivers, particularly around input validation and memory management, and demonstrates why security tools should be rigorously tested for vulnerabilities in their own code. Organizations should also consider implementing principle of least privilege access controls and regular security assessments of all installed software to identify potential attack vectors similar to this one that could be exploited to gain kernel-level access to systems.