CVE-2018-8163 in Excel
Summary
by MITRE
An information disclosure vulnerability exists when Microsoft Excel improperly discloses the contents of its memory, aka "Microsoft Excel Information Disclosure Vulnerability." This affects Microsoft Office, Microsoft Excel.
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Analysis
by VulDB Data Team • 03/11/2023
The vulnerability identified as CVE-2018-8163 represents a critical information disclosure flaw within Microsoft Excel that stems from improper memory handling during specific processing operations. This vulnerability falls under the CWE-200 category of "Information Exposure" and specifically manifests when Excel fails to properly sanitize memory contents during certain data processing scenarios. The flaw enables attackers to potentially access sensitive information that should remain protected within the application's memory space, creating a significant security risk for users who process untrusted or maliciously crafted Excel files.
Technical exploitation of this vulnerability occurs when Excel encounters specific file formats or data structures that trigger improper memory management behaviors. The memory disclosure happens during the rendering or processing of certain spreadsheet elements, particularly when dealing with complex formulas, embedded objects, or malformed data structures. Attackers can leverage this weakness by crafting malicious Excel files that, when opened by vulnerable versions of Excel, cause the application to expose portions of its memory containing sensitive data such as temporary variables, cached data, or even remnants of previously processed files. This behavior aligns with ATT&CK technique T1059.005 for "Command and Scripting Interpreter: Visual Basic" and T1068 for "Exploitation for Privilege Escalation" when combined with other attack vectors.
The operational impact of CVE-2018-8163 extends beyond simple information disclosure, as the exposed memory contents may contain confidential information that could be leveraged for more sophisticated attacks. In enterprise environments where Excel is commonly used for processing sensitive business data, financial reports, or proprietary information, this vulnerability could result in data breaches or intellectual property exposure. The vulnerability affects multiple versions of Microsoft Office and Excel, making it particularly dangerous as it can be exploited across various deployment scenarios from individual workstations to large corporate networks. Organizations using legacy versions of Excel without proper security patches face heightened risk, as the vulnerability exists in versions prior to the respective security updates that address the memory handling flaws.
Mitigation strategies for CVE-2018-8163 should focus on immediate patch deployment and implementation of additional security controls. Microsoft released security updates that address the memory handling issues in affected Excel versions, and organizations must ensure all systems receive these patches promptly. Network administrators should implement email filtering solutions to prevent malicious Excel files from reaching users, while also considering the deployment of application whitelisting policies that restrict execution of untrusted Office files. The vulnerability demonstrates the importance of secure coding practices and memory management, particularly in applications that process complex data structures. Security teams should monitor for indicators of compromise related to this vulnerability and consider implementing memory integrity checks as part of their overall security posture. Organizations should also conduct regular security assessments to identify other potential memory-related vulnerabilities that could be exploited in similar attack scenarios.