CVE-2020-1176 in Windows
Summary
by MITRE
A remote code execution vulnerability exists when the Windows Jet Database Engine improperly handles objects in memory, aka 'Jet Database Engine Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-1051, CVE-2020-1174, CVE-2020-1175.
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Analysis
by VulDB Data Team • 10/17/2020
The vulnerability identified as CVE-2020-1176 represents a critical remote code execution flaw within Microsoft Windows Jet Database Engine, a component that has been integral to various Microsoft applications since the early 1990s. This database engine serves as the foundation for numerous Microsoft Office applications including Access, Outlook, and various other products that rely on the .mdb and .accdb file formats. The vulnerability stems from improper handling of objects in memory, specifically when the engine processes malformed or specially crafted database files that contain maliciously constructed data structures. The flaw exists at the memory management level where the Jet engine fails to properly validate or sanitize object references during the processing of database content, creating opportunities for attackers to execute arbitrary code on affected systems. This vulnerability is particularly concerning because it allows remote attackers to exploit the issue without requiring authentication, making it highly dangerous in networked environments where database files may be accessed through email attachments, web downloads, or shared network resources.
The technical nature of this vulnerability aligns with CWE-125, which describes "Out-of-bounds Read" conditions where a program reads data from memory locations outside the intended boundaries of allocated buffers. The Jet Database Engine's memory handling mechanism fails to properly validate the bounds of memory objects when processing database files, allowing attackers to craft malicious database content that triggers buffer overflows or memory corruption during normal database operations. This flaw operates at the application level rather than at the kernel level, but its impact is equivalent to a kernel-level vulnerability due to the extensive use of the Jet engine across Microsoft applications. The vulnerability specifically manifests when the engine attempts to process database objects that contain crafted data structures designed to cause memory corruption, potentially leading to code execution with the privileges of the user running the affected application. The ATT&CK framework categorizes this vulnerability under T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1203 for "Exploitation for Client Execution" as attackers can leverage this flaw to execute malicious code through compromised database files.
The operational impact of CVE-2020-1176 extends far beyond individual system compromise, as it affects a wide range of Microsoft applications that utilize the Jet Database Engine. Organizations running Microsoft Office suites, database applications, and systems that process database files from untrusted sources face significant risk exposure, particularly in environments where email systems, file sharing services, or web applications might deliver malicious database files to unsuspecting users. The vulnerability's remote execution capability means that attackers can exploit it through various attack vectors including phishing emails containing malicious .mdb files, compromised web applications that serve malicious database content, or through file sharing platforms where users download database files from untrusted sources. The exploitation process typically involves creating a specially crafted database file that, when opened by an affected application, triggers the memory corruption issue and allows attackers to execute arbitrary code on the target system. This vulnerability affects Windows operating systems from Windows 7 through Windows 10, including Windows Server versions, making it particularly dangerous for enterprise environments where these systems are prevalent.
Mitigation strategies for CVE-2020-1176 should focus on both immediate patching and operational security measures to reduce risk exposure. Microsoft released security updates in the May 2020 Patch Tuesday updates that address this vulnerability by correcting the memory handling procedures within the Jet Database Engine. Organizations should prioritize immediate deployment of these patches across all affected systems, particularly those that process database files from external sources or users. Additional defensive measures include implementing email filtering rules that block .mdb and .accdb file attachments, configuring application whitelisting policies to restrict execution of database applications from untrusted sources, and implementing network segmentation to limit exposure of systems that might process database content. Security monitoring should include detection of unusual database file access patterns, particularly when these files are accessed from external sources or when database applications are launched from unexpected locations. The vulnerability also highlights the importance of maintaining up-to-date security practices including regular system updates, network monitoring, and user education regarding the risks of opening database files from untrusted sources. Organizations should also consider implementing sandboxing techniques for database file processing and establishing incident response procedures specifically designed to handle remote code execution vulnerabilities in database processing components.