CVE-2021-28451 in Office
Summary
by MITRE • 04/14/2021
Microsoft Excel Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-28454.
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Analysis
by VulDB Data Team • 04/16/2021
Microsoft Excel contains a remote code execution vulnerability that arises from improper handling of specially crafted files during the parsing process. This flaw exists in the way Excel processes certain file formats and can be exploited by attackers who deliver malicious files to unsuspecting users. The vulnerability specifically affects Microsoft Excel applications across multiple versions and operating systems, making it a widespread concern for enterprise environments that rely heavily on spreadsheet software. The issue stems from insufficient validation of input data within the application's file parsing engine, allowing attackers to craft malicious files that trigger unexpected behavior when opened by vulnerable Excel versions.
The technical exploitation of this vulnerability occurs when a user opens a specially crafted Excel file that contains malicious code or malformed data structures. The flaw enables attackers to execute arbitrary code on the target system with the privileges of the logged-on user, potentially leading to complete system compromise. This remote code execution vulnerability can be leveraged through various attack vectors including email attachments, malicious websites, or compromised file sharing platforms. The exploit typically requires user interaction to open the malicious file, but once executed, it can provide attackers with persistent access to the compromised system. According to the common weakness enumeration framework, this vulnerability maps to CWE-121 which describes heap-based buffer overflow conditions that occur when data is copied into a buffer without proper bounds checking.
The operational impact of CVE-2021-28451 extends beyond individual system compromise to affect entire organizational infrastructures that depend on Microsoft Excel for business operations. Organizations may experience data breaches, system infiltration, and potential lateral movement within their networks as attackers establish persistent footholds. The vulnerability's remote execution capability means that attackers can operate from anywhere in the world without requiring physical access to target systems. Security professionals must consider the implications of this vulnerability within the context of the attack chain framework, where it typically represents the initial compromise phase that enables further malicious activities. The vulnerability's presence in widely deployed software increases the attack surface and creates opportunities for mass exploitation campaigns targeting multiple organizations simultaneously.
Mitigation strategies for this vulnerability should include immediate deployment of Microsoft security patches and updates to address the root cause of the issue. Organizations must implement comprehensive email filtering and web content filtering solutions to prevent users from accessing potentially malicious Excel files. Network segmentation and privileged access controls should be enforced to limit the potential damage from successful exploitation attempts. Security awareness training programs should emphasize the importance of verifying file sources and avoiding suspicious email attachments. Regular system monitoring and endpoint detection capabilities should be deployed to identify anomalous behavior that might indicate exploitation attempts. Additionally, organizations should maintain current threat intelligence feeds to stay informed about emerging attack patterns and exploit techniques targeting this specific vulnerability. The remediation process should follow established security frameworks and include thorough testing of patches in controlled environments before widespread deployment to prevent potential service disruptions.