CVE-2021-1711 in Office
Summary
by MITRE • 01/13/2021
Microsoft Office Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 05/04/2025
Microsoft Office remote code execution vulnerability CVE-2021-1711 represents a critical security flaw in Microsoft Office applications that allows attackers to execute arbitrary code on vulnerable systems. This vulnerability affects multiple Microsoft Office products including Word, Excel, and PowerPoint, making it particularly dangerous due to the widespread use of these applications in enterprise environments. The flaw exists in the way Microsoft Office handles certain file formats and parsing operations, creating opportunities for malicious actors to craft specially crafted documents that trigger unauthorized code execution when opened by victims.
The technical nature of this vulnerability stems from improper input validation and memory handling within Microsoft Office's document processing engines. Attackers can exploit this weakness by embedding malicious code within seemingly legitimate Office documents, particularly those using formats such as .doc, .xls, or .ppt. When a user opens these compromised files, the malicious code executes within the context of the Office application, potentially allowing attackers to gain full control over the affected system. This vulnerability is classified under CWE-121 as a stack-based buffer overflow, where insufficient bounds checking allows attackers to overwrite memory locations and redirect program execution flow.
The operational impact of CVE-2021-1711 extends far beyond individual system compromise, as it provides attackers with a powerful foothold for broader network infiltration. Once an attacker successfully exploits this vulnerability, they can establish persistent access, escalate privileges, and move laterally within the network to target additional systems. The attack surface is particularly large given that Office applications are frequently used for email attachments and document sharing across organizations. This vulnerability aligns with ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute malicious code on target systems. The remote code execution capability makes this vulnerability particularly attractive to threat actors who seek to establish long-term access to compromised environments without detection.
Organizations facing this vulnerability should implement immediate mitigations including timely application of Microsoft security patches, deployment of email filtering solutions to detect and block malicious Office documents, and network segmentation to limit lateral movement. Security teams should also consider implementing application whitelisting policies to restrict execution of unauthorized Office macros and scripts. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that combine multiple security controls to protect against sophisticated attack vectors targeting widely used productivity applications. Regular security assessments and user awareness training are essential components of a comprehensive mitigation strategy for this type of remote code execution vulnerability.