CVE-2018-8634 in Windows
Summary
by MITRE
A remote code execution vulnerability exists in Windows where Microsoft text-to-speech fails to properly handle objects in the memory, aka "Microsoft Text-To-Speech Remote Code Execution Vulnerability." This affects Windows Server 2016, Windows 10, Windows Server 2019, Windows 10 Servers.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/18/2023
The vulnerability identified as CVE-2018-8634 represents a critical remote code execution flaw within Microsoft Windows operating systems that stems from improper handling of memory objects within the text-to-speech component. This vulnerability specifically impacts Windows Server 2016, Windows 10, Windows Server 2019, and Windows 10 Servers, creating a significant attack surface for malicious actors seeking to compromise these systems. The flaw resides in how the Microsoft Text-To-Speech engine processes objects in memory, creating opportunities for arbitrary code execution without requiring authentication or user interaction.
From a technical perspective, this vulnerability manifests as a memory corruption issue that occurs when the text-to-speech engine encounters malformed or specially crafted input data. The underlying flaw can be categorized as a buffer overflow or memory management error, which falls under CWE-121, which describes "Stack-based Buffer Overflow" and related memory corruption vulnerabilities. The vulnerability arises when the system attempts to process text input that gets converted to speech, where the conversion process fails to properly validate or sanitize the input before processing it in memory. Attackers can exploit this by crafting malicious text content that, when processed by the text-to-speech engine, causes memory corruption that can be leveraged to execute arbitrary code with the privileges of the affected process.
The operational impact of CVE-2018-8634 is severe and far-reaching across enterprise environments, particularly given the widespread use of Windows operating systems in corporate networks. The vulnerability enables attackers to achieve remote code execution without requiring user interaction, making it particularly dangerous for targeted attacks. Once exploited, the vulnerability allows attackers to gain full control over the affected system, potentially leading to data exfiltration, lateral movement within networks, and establishment of persistent backdoors. The attack vector typically involves delivering malicious text content through various channels including email, web applications, or file attachments that trigger the text-to-speech functionality when processed by the vulnerable Windows systems. This vulnerability is particularly concerning in server environments where Windows Server 2016 and Windows Server 2019 are commonly deployed as enterprise infrastructure components.
Security professionals should note that this vulnerability aligns with several ATT&CK techniques including T1059.007 for Windows Command Shell and T1059.001 for Command and Scripting Interpreter, as exploitation typically involves executing malicious code through system processes. The vulnerability also maps to ATT&CK technique T1106 for Execution through API calls, since the exploitation leverages legitimate system APIs for text processing. Organizations should implement immediate mitigations including applying Microsoft security patches, implementing network segmentation to limit access to vulnerable systems, and monitoring for unusual text processing activities. Additionally, the vulnerability demonstrates the importance of proper input validation and memory management practices in system components, reinforcing the need for robust software development lifecycle security practices. The presence of this vulnerability in widely deployed Windows versions underscores the critical importance of maintaining up-to-date security patches and implementing comprehensive vulnerability management programs to protect against similar memory corruption issues.