CVE-2014-1817 in Windows
Summary
by MITRE
usp10.dll in Uniscribe (aka the Unicode Script Processor) in Microsoft Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT Gold and 8.1, Office 2007 SP3 and 2010 SP1 and SP2, Live Meeting 2007 Console, Lync 2010 and 2013, Lync 2010 Attendee, and Lync Basic 2013 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted EMF+ record in a font file, aka "Unicode Scripts Processor Vulnerability."
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Analysis
by VulDB Data Team • 06/22/2021
The vulnerability described in CVE-2014-1817 represents a critical memory corruption flaw within the Unicode Script Processor component of Microsoft Windows operating systems and Office applications. This issue specifically affects the usp10.dll library responsible for processing Unicode text scripts and rendering complex typography in applications. The vulnerability arises from improper handling of Enhanced Metafile Plus (EMF+) records embedded within font files, creating a pathway for remote code execution or denial of service conditions. The affected systems span multiple Windows versions including server and client operating systems, as well as various Microsoft Office and Lync products, indicating a widespread impact across the Microsoft ecosystem.
The technical exploitation of this vulnerability occurs when the affected system processes a specially crafted font file containing malicious EMF+ records. These records trigger memory corruption within the Uniscribe engine's handling of Unicode text processing, specifically in how it manages script analysis and text rendering operations. The flaw stems from insufficient validation of EMF+ record structures within font files, allowing attackers to manipulate memory layout and potentially execute arbitrary code with the privileges of the affected process. This type of vulnerability falls under CWE-121, heap-based buffer overflow, and represents a classic case of improper input validation leading to memory corruption. The attack vector is particularly concerning because it can be triggered through legitimate font processing operations, making it difficult to detect and prevent through traditional security measures.
The operational impact of CVE-2014-1817 extends beyond simple denial of service conditions to potentially enable full system compromise. When exploited successfully, the vulnerability allows attackers to execute code remotely without requiring user interaction, making it particularly dangerous in enterprise environments where multiple systems may be exposed. The affected applications and operating systems represent critical infrastructure components that are widely deployed across organizations, meaning a successful exploitation could lead to data breaches, privilege escalation, and persistent access to network resources. The vulnerability's presence in Office applications and Lync products specifically increases the attack surface by enabling exploitation through email attachments, document sharing, and collaboration platforms. According to ATT&CK framework, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1068 (Exploitation for Privilege Escalation) techniques, as it enables remote code execution and potential privilege escalation.
Mitigation strategies for CVE-2014-1817 should focus on immediate patch deployment through Microsoft's security updates, which address the underlying memory corruption issue in the Uniscribe engine. Organizations should implement strict font file validation and filtering mechanisms, particularly for email attachments and document sharing platforms, to prevent processing of potentially malicious font files. Network segmentation and application whitelisting can help limit the potential impact of successful exploitation by restricting access to critical systems. Additionally, implementing monitoring solutions that detect anomalous font processing activities and memory corruption patterns can provide early warning of attempted exploitation. System administrators should also consider disabling unnecessary font processing capabilities in applications where they are not required for core functionality, reducing the attack surface for this and similar vulnerabilities. The remediation approach aligns with NIST SP 800-128 guidelines for vulnerability management and Microsoft's recommended security hardening practices for enterprise environments.