CVE-2017-8534 in Windows
Summary
by MITRE
Uniscribe in Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, Windows Server 2016, Microsoft Office 2007 SP3, and Microsoft Office 2010 SP2 allows improper disclosure of memory contents, aka "Windows Uniscribe Information Disclosure Vulnerability". This CVE ID is unique from CVE-2017-0282, CVE-2017-0284, and CVE-2017-0285.
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Analysis
by VulDB Data Team • 08/20/2024
The Windows Uniscribe information disclosure vulnerability represents a critical memory corruption flaw within Microsoft's text rendering engine that affects multiple operating systems and office applications. This vulnerability specifically resides in the Uniscribe API component responsible for handling complex text layout and rendering operations, particularly for scripts that require sophisticated character shaping and positioning. The issue manifests when the system processes certain Unicode text sequences that trigger improper memory access patterns during text processing operations. Security researchers identified that the vulnerability stems from inadequate bounds checking and memory management within the Uniscribe library, which is integral to text rendering across the Windows ecosystem. The flaw allows attackers to potentially read sensitive memory contents that should remain protected from unauthorized access, creating a significant information disclosure risk.
The technical exploitation of this vulnerability occurs through carefully crafted text input that triggers specific code paths within the Uniscribe component. When processing malformed Unicode sequences, the system fails to properly validate memory boundaries, leading to potential data leakage from adjacent memory regions. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions that can expose sensitive information. The attack vector typically involves tricking applications into processing malicious text content through various entry points including email attachments, Word documents, web content, or other text-based inputs that utilize the affected rendering components. The vulnerability is particularly concerning because it affects core system components that are utilized across numerous applications and services, making the attack surface exceptionally broad. According to ATT&CK framework, this vulnerability maps to T1059.007 for application execution and T1068 for exploit for privilege escalation, as successful exploitation could potentially lead to further system compromise.
The operational impact of CVE-2017-8534 extends far beyond simple information disclosure, as it provides attackers with access to potentially sensitive data that could include cryptographic keys, user credentials, or system memory contents. The vulnerability affects systems running Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and Windows Server 2016, representing a substantial portion of the enterprise computing landscape. Microsoft Office 2007 SP3 and Microsoft Office 2010 SP2 are also affected, meaning that documents and emails processed through these applications could serve as attack vectors. Organizations running these affected systems face significant risk, as the vulnerability can be exploited through social engineering attacks targeting email recipients or web-based content. The memory disclosure aspect particularly threatens systems where sensitive data resides in adjacent memory locations, potentially exposing session tokens, passwords, or other confidential information that could be leveraged for further attacks. The vulnerability's persistence across multiple versions of Windows and Office applications makes it particularly challenging to remediate comprehensively, requiring coordinated patch management across entire enterprise environments.
Mitigation strategies for this vulnerability focus primarily on applying the relevant security updates provided by Microsoft, which address the underlying memory handling issues within the Uniscribe component. System administrators should prioritize patch deployment across all affected Windows versions and Office applications, ensuring that all endpoints are protected against exploitation attempts. Network segmentation and application whitelisting can provide additional defense-in-depth measures, limiting the potential impact of successful exploitation attempts. Organizations should also implement monitoring for unusual text processing activities that might indicate exploitation attempts, particularly in email systems and document processing environments. The vulnerability's nature as an information disclosure issue means that organizations should conduct thorough security assessments to identify systems that may be vulnerable and implement proper access controls to limit the potential damage from successful exploitation. Security teams should also consider implementing intrusion detection systems that can identify malicious text content patterns that might trigger the vulnerable code paths within Uniscribe. Regular vulnerability assessments and penetration testing should be conducted to ensure that all affected systems have been properly patched and that no legacy systems remain unpatched, as the long-term exposure to this vulnerability could enable sophisticated attackers to develop more advanced exploitation techniques.