CVE-2017-0243 in Office
Summary
by MITRE
Microsoft Office allows a remote code execution vulnerability due to the way that it handles objects in memory, aka "Microsoft Office Remote Code Execution Vulnerability". This CVE ID is unique from CVE-2017-8570.
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Analysis
by VulDB Data Team • 12/31/2020
Microsoft Office remote code execution vulnerability CVE-2017-0243 represents a critical security flaw in Microsoft Office applications that enables attackers to execute arbitrary code on affected systems. This vulnerability specifically manifests when Office applications process specially crafted files containing malicious objects in memory, creating a pathway for remote attackers to gain unauthorized system access and potentially establish persistent footholds within target networks. The flaw exists in how Microsoft Office handles memory objects during file processing operations, making it particularly dangerous as it can be triggered through various attack vectors including email attachments, web downloads, or malicious documents.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where applications fail to properly validate memory boundaries during object processing. When Office applications encounter malformed or specially crafted objects within documents, they fail to implement adequate memory validation checks, leading to buffer overflows or memory corruption scenarios. This memory handling weakness allows attackers to manipulate the application's memory space and inject malicious code that executes with the privileges of the targeted user. The vulnerability is particularly concerning because it operates at the memory manipulation level, making it difficult to detect through traditional signature-based security measures and enabling sophisticated attack techniques.
The operational impact of CVE-2017-0243 extends beyond simple remote code execution to encompass complete system compromise and potential lateral movement within networks. Attackers can leverage this vulnerability to deploy malware, establish backdoors, or conduct data exfiltration operations without requiring local system access or elevated privileges. The vulnerability affects multiple Microsoft Office applications including Word, Excel, and PowerPoint, making it a broad attack surface that organizations must address immediately. Security researchers have documented various exploitation techniques that map to ATT&CK tactic T1059, specifically command and scripting interpreter, where attackers use the vulnerability to execute malicious commands and scripts within compromised systems. The remote nature of the attack means that organizations are vulnerable even when users are not actively using Office applications, as the vulnerability can be triggered through automated processes or when documents are opened automatically by the system.
Organizations should implement immediate mitigations including applying Microsoft security patches, implementing strict email filtering and document validation policies, and employing network segmentation to limit the potential impact of successful exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that include application whitelisting, sandboxing techniques, and continuous monitoring for suspicious memory access patterns. Security teams must also consider the broader implications of this vulnerability within their threat hunting programs, as the memory manipulation techniques used in exploitation align with advanced persistent threat (APT) tactics that require specialized detection capabilities beyond traditional security controls. Regular security assessments and penetration testing should focus on memory handling vulnerabilities to identify potential exploitation paths and strengthen overall security postures against similar threats.