CVE-2020-0650 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'. This CVE ID is unique from CVE-2020-0651, CVE-2020-0653.
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Analysis
by VulDB Data Team • 03/21/2024
The vulnerability identified as CVE-2020-0650 represents a critical remote code execution flaw within Microsoft Excel software that stems from improper handling of objects in memory. This vulnerability specifically affects Microsoft Excel versions prior to the security updates released in January 2020, making it particularly dangerous for organizations that maintain outdated software environments. The flaw exists in how Excel processes certain file objects during memory allocation and management, creating opportunities for attackers to execute arbitrary code on affected systems. This issue is classified under CWE-125 as an "Out-of-bounds Read" vulnerability, where the software fails to properly validate memory boundaries when processing maliciously crafted Excel files. The vulnerability is particularly concerning because it can be exploited through social engineering tactics, where users unknowingly open malicious Excel files that contain specially crafted objects designed to trigger the memory handling flaw. Attackers can leverage this vulnerability to gain full control of affected systems, potentially leading to data exfiltration, persistence mechanisms, and lateral movement within network environments.
The technical exploitation of CVE-2020-0650 follows the ATT&CK framework's technique T1203 "Exploitation for Client Execution" and T1059 "Command and Scripting Interpreter" where adversaries manipulate Excel's memory management routines to execute malicious payloads. When a user opens a specially crafted Excel file, the software's memory handling routines fail to properly validate the structure of embedded objects, allowing attackers to overwrite memory locations with malicious code. The vulnerability is particularly dangerous because it operates at the memory management level, bypassing many traditional security controls and sandboxing mechanisms that protect against file-based attacks. This flaw is categorized as a heap-based buffer overflow when Excel attempts to process malformed objects, creating a scenario where attackers can control the execution flow of the application. The vulnerability's remote execution capability means that no local system access is required for exploitation, as the malicious payload can be delivered through email attachments, web downloads, or compromised websites that users might inadvertently access.
The operational impact of CVE-2020-0650 extends far beyond simple application compromise, as it provides attackers with a powerful foothold for enterprise-wide attacks. Organizations running unpatched Excel installations face significant risk of complete system compromise, with potential for privilege escalation and data breach scenarios. The vulnerability affects not only individual workstations but also enterprise environments where Excel is commonly used for data processing, financial analysis, and collaborative document sharing. Attackers can leverage this vulnerability as part of multi-stage attack campaigns, using the initial compromise to establish persistence mechanisms such as scheduled tasks, registry modifications, or hidden processes. The vulnerability's exploitation typically requires minimal user interaction, often just opening a malicious file, making it particularly effective for phishing campaigns. Organizations that rely heavily on Excel for business operations face significant operational disruption if this vulnerability is exploited, potentially leading to business continuity issues and regulatory compliance violations. The vulnerability's classification under the MITRE ATT&CK framework as a privilege escalation vector means that successful exploitation could allow attackers to move laterally within networks, potentially accessing sensitive databases, enterprise applications, and other critical infrastructure components.
Mitigation strategies for CVE-2020-0650 focus primarily on immediate patch deployment and implementation of defensive measures to reduce attack surface. Microsoft released security update MS19-011 in January 2020 that addresses this vulnerability, making it essential for organizations to apply the patch promptly across all affected systems. Beyond patching, organizations should implement email filtering solutions that can identify and block suspicious Excel attachments, particularly those with macros or embedded objects that could trigger the vulnerability. Network segmentation and application whitelisting can help limit the potential impact of successful exploitation by preventing lateral movement within compromised environments. Security teams should also consider implementing behavioral monitoring solutions that can detect anomalous Excel processes or memory access patterns that might indicate exploitation attempts. Regular security awareness training for end users remains critical, as the vulnerability often relies on social engineering to deliver malicious payloads. Organizations should also maintain comprehensive backup strategies and incident response procedures specifically designed to handle remote code execution vulnerabilities, ensuring rapid recovery and minimal business disruption if exploitation occurs. The vulnerability's nature makes it particularly important to monitor for indicators of compromise such as unusual network connections, unexpected process creation, or memory access violations that could signal exploitation attempts.