CVE-2025-21395 in Office
Summary
by MITRE • 01/14/2025
Microsoft Access Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 07/02/2025
This vulnerability represents a critical remote code execution flaw in Microsoft Access software that allows attackers to execute arbitrary code on affected systems without authentication. The vulnerability stems from improper input validation within the application's handling of specially crafted files or data structures, creating an opportunity for malicious actors to exploit memory corruption issues through crafted Office documents or database files. According to CWE-121, this falls under stack-based buffer overflow conditions where insufficient bounds checking permits attackers to overwrite adjacent memory locations with malicious payloads. The flaw exists in the way Microsoft Access processes certain database objects and file formats, particularly affecting versions that handle external data sources or complex query structures.
The operational impact of this vulnerability extends far beyond simple exploitation as it provides attackers with complete system compromise capabilities through techniques such as DLL side-loading or direct code injection methods. Attackers can leverage this vulnerability to establish persistent access, escalate privileges, and move laterally within networks without requiring user interaction or elevated permissions initially. The vulnerability aligns with ATT&CK technique T1203 by enabling malicious file execution, while also supporting T1059 for command and scripting interpreter usage once initial access is achieved. Organizations running vulnerable versions of Microsoft Access face significant risk of data breaches, system compromise, and potential lateral movement throughout their infrastructure.
Mitigation strategies must focus on immediate patch deployment as provided by Microsoft's security updates, alongside network segmentation and monitoring of suspicious file handling activities. Security teams should implement strict file validation policies, disable unnecessary Office features, and deploy application control measures to prevent execution of untrusted files. The vulnerability demonstrates the importance of maintaining up-to-date software versions and implementing defense-in-depth strategies that combine endpoint protection, network monitoring, and user education programs. Additional controls such as disabling macro execution in Office applications, implementing strict access controls for database files, and conducting regular security assessments help reduce the attack surface and prevent exploitation attempts.
Organizations should also consider implementing automated threat hunting procedures to detect potential exploitation attempts through anomalous file processing patterns or unusual network connections originating from Access processes. The vulnerability highlights the persistent nature of Office-related exploits in enterprise environments and underscores the necessity for continuous security monitoring and rapid incident response capabilities. Regular vulnerability assessments, penetration testing, and security awareness training form essential components of a comprehensive defense strategy against such sophisticated attack vectors that can bypass traditional security controls through carefully crafted malicious payloads designed to exploit specific application flaws.