CVE-2020-0901 in Excel
Summary
by MITRE
A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory, aka 'Microsoft Excel Remote Code Execution Vulnerability'.
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Analysis
by VulDB Data Team • 10/16/2020
This vulnerability represents a critical remote code execution flaw in Microsoft Excel that stems from improper memory handling during object processing. The vulnerability specifically manifests when Excel encounters specially crafted malicious objects within spreadsheet files, leading to arbitrary code execution on affected systems. The flaw exists at the memory management level where Excel fails to properly validate and sanitize object references during the parsing process, creating a pathway for attackers to inject and execute malicious code remotely.
The technical exploitation of this vulnerability leverages memory corruption principles that align with common CWE categories including CWE-125 and CWE-787, which address out-of-bounds read and write conditions. Attackers can craft malicious Excel files containing malformed objects that trigger buffer overflows or memory corruption when processed by vulnerable Excel versions. This allows adversaries to execute arbitrary code with the privileges of the logged-on user, potentially leading to full system compromise. The vulnerability is particularly dangerous because it can be triggered through legitimate Office file formats without requiring special privileges or user interaction beyond opening the malicious file.
The operational impact of CVE-2020-0901 extends beyond simple remote code execution to encompass complete system compromise and data exfiltration capabilities. Once exploited, attackers can establish persistent access, deploy additional malware, or escalate privileges to system-level access. The vulnerability affects multiple Microsoft Office versions including Excel 2016, 2019, and Office 2016 for Mac, making it a widespread concern across enterprise environments where Excel is commonly used for document sharing and collaboration. Organizations utilizing cloud-based Office 365 services remain vulnerable as the underlying Excel engine components are affected regardless of deployment model.
Mitigation strategies should include immediate deployment of Microsoft's security patches and updates as part of comprehensive vulnerability management programs. Organizations should implement strict file validation policies and restrict the execution of Office files from untrusted sources through email filtering solutions and network access controls. Network segmentation and privileged access controls can limit the potential impact of successful exploitation attempts. Security teams should also monitor for indicators of compromise including unusual network connections, file execution patterns, and anomalous user behavior that may indicate exploitation attempts. Additionally, implementing application whitelisting solutions and disabling unnecessary Office features can significantly reduce the attack surface and prevent exploitation of this vulnerability through various attack vectors including phishing campaigns and malicious file attachments.