CVE-2020-1193 in Office
Summary
by MITRE
<p>A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.</p> <p>Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Excel. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) containing a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.</p> <p>The security update addresses the vulnerability by correcting how Microsoft Excel handles objects in memory.</p>
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Analysis
by VulDB Data Team • 02/24/2026
The vulnerability identified as CVE-2020-1193 represents a critical remote code execution flaw in Microsoft Excel software that stems from improper handling of objects in memory. This weakness falls under the broader category of memory corruption vulnerabilities and aligns with CWE-125, which describes out-of-bounds read conditions where an attacker can access memory locations beyond the intended boundaries. The flaw specifically affects how Excel processes certain file formats and internal objects, creating opportunities for malicious code injection that can execute with the privileges of the currently logged-on user. This vulnerability operates at the intersection of software security and social engineering, as successful exploitation requires user interaction with maliciously crafted files, making it particularly dangerous in enterprise environments where users frequently handle external documents.
The technical exploitation of this vulnerability involves crafting specially formatted Excel files that trigger memory corruption when processed by affected versions of the software. When Excel attempts to parse these malformed objects, it fails to properly validate memory boundaries, allowing attackers to execute arbitrary code within the application's memory space. This memory corruption can occur during normal file processing operations, making the attack surface particularly broad and difficult to detect. The vulnerability's exploitation pathway follows the typical ATT&CK technique T1203 - Exploitation for Client Execution, where attackers leverage application vulnerabilities to execute code on target systems. The memory handling failure creates a condition where attacker-controlled data can overwrite critical program memory, potentially leading to complete system compromise when administrative privileges are present.
The operational impact of CVE-2020-1193 extends far beyond simple code execution, as successful exploitation can result in full system compromise when users operate with administrative rights. This vulnerability enables attackers to install malicious software, modify or delete critical data, and create new user accounts with elevated privileges, effectively granting them persistent access to affected systems. The risk assessment reveals that users with standard privileges experience reduced impact compared to administrative users, though this does not eliminate the threat entirely since privilege escalation techniques can still be employed. Organizations using affected Excel versions face significant exposure, particularly in environments where users frequently process external documents or receive email attachments from untrusted sources. The vulnerability's remote exploitation capability means attackers can target systems without requiring physical access, making it particularly concerning for enterprise security postures.
Mitigation strategies for CVE-2020-1193 should prioritize immediate patch deployment through Microsoft's security updates, as the vulnerability has been addressed in subsequent releases. Organizations should implement comprehensive email filtering solutions that can identify and block malicious Excel files before they reach users, utilizing both content filtering and attachment scanning capabilities. Security awareness training programs must emphasize the dangers of opening unexpected Excel files and encourage users to verify document sources before processing. Network-based protections such as application whitelisting can prevent unauthorized Excel versions from executing, while endpoint detection and response solutions can identify suspicious memory access patterns that may indicate exploitation attempts. The remediation process should include thorough vulnerability assessments of all systems running affected Excel versions, along with regular security updates and monitoring for any signs of exploitation attempts. Additionally, organizations should consider implementing Microsoft's Office Macro security settings and disabling automatic execution of macros from untrusted sources to reduce the attack surface.