CVE-2018-0796 in Excel
Summary
by MITRE
Microsoft Excel in Microsoft Office 2007, Microsoft Office 2010, Microsoft Office 2013, and Microsoft Office 2016 allows a remote code execution vulnerability due to the way objects are handled in memory, aka "Microsoft Excel Remote Code Execution Vulnerability".
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Analysis
by VulDB Data Team • 01/29/2021
The Microsoft Excel Remote Code Execution Vulnerability CVE-2018-0796 represents a critical security flaw affecting multiple versions of Microsoft Office including Office 2007, 2010, 2013, and 2016. This vulnerability stems from improper handling of objects within memory during Excel's processing operations, creating an exploitable condition that enables remote code execution attacks. The flaw specifically manifests when Excel processes specially crafted malicious files that contain malformed objects designed to trigger memory corruption during normal operation.
This vulnerability operates through a classic buffer overflow mechanism where maliciously constructed data structures within Excel files cause memory corruption when the application attempts to parse and render these objects. The technical implementation involves the manipulation of object references and memory allocation patterns that lead to arbitrary code execution privileges when exploited by attackers. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which directly relates to improper memory handling during object processing within the Excel application's memory management subsystem.
The operational impact of this vulnerability is severe as it allows attackers to execute arbitrary code on vulnerable systems with the privileges of the current user. Attackers can leverage this flaw through various attack vectors including malicious email attachments, compromised websites, or malicious documents shared via collaboration platforms. Once successfully exploited, the vulnerability can lead to complete system compromise, data exfiltration, persistent backdoor installation, and lateral movement within network environments. The attack surface is particularly broad since Excel is widely used across enterprise environments and users frequently open documents from untrusted sources.
Security professionals should implement multiple layers of defense to mitigate this vulnerability. Immediate remediation involves applying Microsoft's security patches and updates released in response to this CVE. Organizations should also deploy application whitelisting solutions to restrict execution of unauthorized Excel files, implement email filtering solutions to detect and block malicious attachments, and conduct regular security awareness training for users to recognize potential social engineering attacks. Network segmentation and monitoring solutions should be enhanced to detect unusual Excel process behavior or outbound connections that might indicate exploitation attempts. According to ATT&CK framework, this vulnerability maps to T1059.005 (Command and Scripting Interpreter: Visual Basic) and T1203 (Exploitation for Client Execution) techniques, highlighting the need for comprehensive endpoint detection and response capabilities. The vulnerability's exploitation typically requires user interaction with malicious files, making user education and security policy enforcement critical components of the overall mitigation strategy.