CVE-2002-0617 in Excel
Summary
by MITRE
The Macro Security Model in Microsoft Excel 2000 and 2002 for Windows allows remote attackers to execute code by creating a hyperlink on a drawing shape in a source workbook that points to a destination workbook containing an autoexecute macro, aka "Hyperlinked Excel Workbook Macro Bypass."
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Analysis
by VulDB Data Team • 06/17/2024
The vulnerability described in CVE-2002-0617 represents a significant security flaw in Microsoft Excel 2000 and 2002 that exploits the macro security model through a sophisticated bypass technique. This vulnerability specifically targets the way Excel handles hyperlinks within drawing objects, creating a pathway for remote code execution that circumvents standard security mechanisms. The flaw operates by leveraging the interaction between hyperlink functionality and macro execution, allowing attackers to craft malicious workbooks that can execute code without proper user consent or awareness.
The technical implementation of this vulnerability relies on the manipulation of drawing shapes within Excel workbooks to contain hyperlinks that point to other workbooks containing autoexecute macros. When a user opens a workbook containing such a drawing shape, the hyperlink triggers the execution of macros in the linked workbook without requiring explicit user interaction to enable macros or acknowledge the security risk. This bypass occurs because Excel's security model fails to properly validate the execution context of macros referenced through hyperlinked drawing objects, creating a gap in the security architecture that attackers can exploit to deliver malicious payloads.
From an operational perspective, this vulnerability poses a substantial risk to organizations relying on Microsoft Excel for document processing and collaboration. The attack vector is particularly dangerous because it can be delivered through seemingly innocuous workbook files that appear legitimate to users. The vulnerability enables attackers to execute arbitrary code on target systems with the privileges of the user running Excel, potentially leading to complete system compromise, data exfiltration, or further network infiltration. The remote execution capability means that attackers can deliver these malicious workbooks through email attachments, shared network drives, or web downloads without requiring local access to the target system.
The security implications extend beyond simple code execution to encompass broader system compromise and data security breaches. This vulnerability directly relates to CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK techniques involving execution through macro and script environments. The flaw demonstrates how seemingly minor implementation gaps in security models can create significant attack surfaces, particularly when dealing with complex interaction patterns between different Excel features. Organizations using these older Excel versions face heightened risk as the vulnerability remains exploitable due to the lack of modern security controls that would otherwise prevent such bypass scenarios.
Mitigation strategies for this vulnerability require a combination of immediate remediation actions and long-term security improvements. Organizations should immediately update to supported versions of Microsoft Office that address this vulnerability, as Microsoft released patches and updates to fix the macro security model flaws. Users should implement strict macro security policies, disable macros by default, and employ application whitelisting solutions to prevent unauthorized code execution. Network security controls such as email filtering and web proxy configurations can help reduce the likelihood of users encountering malicious workbooks. Additionally, security awareness training should emphasize the dangers of opening unexpected workbook files, particularly those containing drawing objects or hyperlinks that may trigger automatic execution sequences. The vulnerability highlights the importance of maintaining up-to-date software and implementing layered security approaches to defend against sophisticated attack techniques that exploit interaction gaps between different application features.