CVE-2017-8692 in Windows
Summary
by MITRE
The Windows Uniscribe component on Microsoft Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allows remote code execution vulnerability when it fails to properly handle objects in memory, aka "Uniscribe Remote Code Execution Vulnerability".
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/12/2021
The Windows Uniscribe component represents a critical vulnerability identified as CVE-2017-8692 that affects multiple Microsoft Windows operating systems including Windows 8.1, Windows Server 2012, Windows RT 8.1, various Windows 10 versions, and Windows Server 2016. This vulnerability falls under the Common Weakness Enumeration category CWE-125, which describes out-of-bounds read conditions that can lead to memory corruption and arbitrary code execution. The flaw specifically manifests when Uniscribe fails to properly handle objects in memory, creating a dangerous scenario where malicious actors can exploit the component's memory management deficiencies. Uniscribe serves as a crucial text processing engine responsible for handling complex script rendering, including bidirectional text, ligatures, and advanced typography features that are essential for international character support in Windows applications.
The technical exploitation of this vulnerability occurs through improper memory handling within the Uniscribe text processing engine, which can result in heap-based buffer overflows or use-after-free conditions when processing specially crafted text input. Attackers can leverage this weakness by constructing malicious input that triggers the vulnerable code path during text rendering operations, potentially leading to remote code execution with the privileges of the targeted user. The vulnerability is particularly dangerous because Uniscribe is deeply integrated into Windows applications and web browsers, making it accessible through various attack vectors including malicious websites, email attachments, and word processing documents. This allows threat actors to execute code remotely without requiring local system access, making the exploit particularly attractive for large-scale attacks.
The operational impact of CVE-2017-8692 extends beyond simple remote code execution, as it provides attackers with a powerful foothold for further system compromise and lateral movement within networks. Organizations running affected Windows versions face significant risk of data breaches, system takeovers, and persistent threats that can remain undetected for extended periods. The vulnerability's presence across multiple Windows versions and server configurations creates widespread exposure, particularly affecting enterprise environments where legacy systems are still operational. Security researchers have documented this vulnerability in relation to the attack technique T1059, which involves command and script interpreters, as attackers can use the executed code to establish persistence mechanisms and deploy additional malware. The vulnerability also aligns with T1068, which describes additional attack surface exposure through remote access tools, as the compromised system can be used as a launchpad for further attacks.
Mitigation strategies for CVE-2017-8692 primarily focus on applying Microsoft security updates and patches released through Windows Update or Microsoft Update Catalog. Organizations should prioritize immediate patch deployment across all affected systems, particularly those running Windows 8.1, Windows Server 2012, and various Windows 10 versions. Network administrators should implement additional defensive measures including web application firewalls, content filtering solutions, and browser hardening configurations that can help reduce the attack surface for exploitation attempts. The implementation of exploit prevention techniques such as Data Execution Prevention, Address Space Layout Randomization, and Control Flow Guard can provide additional layers of protection against exploitation attempts. Security teams should also monitor for indicators of compromise related to this vulnerability, including unusual network connections, process creation patterns, and memory access violations that may indicate successful exploitation attempts. Additionally, organizations should conduct comprehensive vulnerability assessments to identify any remaining systems that may still be running unsupported Windows versions that could be vulnerable to similar memory corruption issues.