CVE-2018-8476 in Windows
Summary
by MITRE
A remote code execution vulnerability exists in the way that Windows Deployment Services TFTP Server handles objects in memory, aka "Windows Deployment Services TFTP Server Remote Code Execution Vulnerability." This affects Windows Server 2012 R2, Windows Server 2008, Windows Server 2012, Windows Server 2019, Windows Server 2016, Windows Server 2008 R2, Windows 10 Servers.
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Analysis
by VulDB Data Team • 07/15/2024
The vulnerability CVE-2018-8476 represents a critical remote code execution flaw within Windows Deployment Services TFTP Server component that operates at the memory handling level. This issue stems from improper validation of objects within the TFTP server's memory management system, creating an exploitable condition that allows attackers to execute arbitrary code on affected systems. The vulnerability specifically targets the TFTP (Trivial File Transfer Protocol) server functionality that is part of the Windows Deployment Services suite, which is commonly used for operating system deployment and network booting operations in enterprise environments.
The technical flaw manifests when the TFTP server processes certain malformed or specially crafted memory objects during file transfer operations. This memory handling error creates a buffer overflow condition or memory corruption vulnerability that can be leveraged by remote attackers to inject and execute malicious code with the privileges of the TFTP service account. The vulnerability affects multiple Windows Server versions including 2008, 2008 R2, 2012, 2012 R2, 2016, and 2019, as well as Windows 10 Servers, indicating a widespread impact across the Windows server ecosystem. According to CWE classification, this vulnerability maps to CWE-121, which describes heap-based buffer overflow conditions, and potentially CWE-787, which covers out-of-bounds write vulnerabilities in heap memory.
The operational impact of this vulnerability is severe as it enables attackers to achieve complete system compromise without requiring authentication or local access. An attacker can exploit this vulnerability by sending specially crafted TFTP requests to the affected server, potentially leading to privilege escalation and persistent access within the network. The vulnerability's remote nature makes it particularly dangerous as it can be exploited from any location on the network, and the TFTP protocol is often enabled by default in enterprise environments, increasing the attack surface. This vulnerability directly aligns with ATT&CK technique T1195.001, which covers the use of network protocols for execution, and T1059.001, involving command and scripting interpreter usage for remote code execution.
Mitigation strategies for CVE-2018-8476 should prioritize immediate patch deployment through Microsoft's security updates, as this vulnerability has been addressed in the August 2018 security bulletin. Organizations should also implement network segmentation to limit access to TFTP servers, disable unnecessary TFTP services where possible, and monitor network traffic for suspicious TFTP activity. Network administrators should consider implementing firewall rules to restrict TFTP traffic to trusted networks only, and conduct thorough vulnerability assessments to identify all affected systems within their infrastructure. Additionally, implementing intrusion detection systems that can identify potential exploitation attempts and maintaining up-to-date security monitoring tools will help detect and respond to exploitation attempts targeting this vulnerability. The vulnerability's classification as a remote code execution flaw necessitates immediate remediation and comprehensive security posture improvements across affected environments.