CVE-2017-8567 in Excel
Summary
by MITRE
A remote code execution vulnerability exists in Microsoft Excel for Mac 2011 when it fails to properly handle objects in memory, aka "Microsoft Office Remote Code Execution".
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Analysis
by VulDB Data Team • 01/11/2021
The vulnerability identified as CVE-2017-8567 represents a critical remote code execution flaw within Microsoft Excel for Mac 2011, classified under CWE-125 as an "Out-of-Bounds Read" condition that can lead to arbitrary code execution. This vulnerability stems from the application's insufficient memory management when processing specially crafted Excel files, specifically failing to properly handle objects in memory during file parsing operations. The flaw manifests when Excel attempts to parse maliciously constructed spreadsheet elements that trigger improper memory access patterns, potentially allowing attackers to execute arbitrary code on affected systems.
The technical exploitation of this vulnerability occurs through a carefully crafted Excel file that contains malformed objects designed to trigger memory corruption during the parsing process. When a user opens such a malicious file, the Excel application's memory handling routines fail to validate object boundaries properly, leading to memory corruption that can be leveraged to execute malicious code with the privileges of the logged-in user. This type of vulnerability falls under the ATT&CK technique T1203 - Exploitation for Client Execution, where attackers exploit software vulnerabilities to execute code on target systems. The vulnerability is particularly concerning because it operates entirely within the context of legitimate spreadsheet processing, making it difficult to detect through traditional security measures.
The operational impact of CVE-2017-8567 extends beyond simple code execution, as successful exploitation can lead to complete system compromise and data exfiltration. Attackers can leverage this vulnerability to install backdoors, steal sensitive information, or establish persistent access to affected systems. The vulnerability affects Microsoft Excel for Mac 2011 specifically, making it a targeted threat for users in environments where this older version remains in use. Organizations with legacy systems running this software are particularly at risk, as the vulnerability can be exploited through various attack vectors including email attachments, web downloads, or malicious documents shared through collaborative platforms.
Mitigation strategies for CVE-2017-8567 should prioritize immediate software updates and patches provided by Microsoft, as the vulnerability was addressed through security updates released in 2017. Organizations should implement strict email filtering and document validation procedures to prevent users from opening potentially malicious Excel files. Network segmentation and endpoint protection solutions should be deployed to monitor for suspicious file execution patterns. Additionally, user education regarding the dangers of opening untrusted spreadsheet files remains crucial, as social engineering remains a common attack vector for exploiting such vulnerabilities. The remediation process should include comprehensive vulnerability assessments to identify systems running unsupported versions of Excel, as well as regular security updates to maintain protection against similar memory corruption vulnerabilities.