Executive brief
Microsoft Visual Basic for Applications (VBA) is a tool used to automate tasks within Microsoft Office documents. A security flaw in how this tool loads necessary files could allow an attacker to take control of a user's computer if the user opens a document in a folder containing a malicious file. This vulnerability has been exploited in the wild and can lead to full system compromise or unauthorized access to sensitive data.
Technical details
An untrusted search path vulnerability (CWE-426) exists in VBE6.dll within Microsoft Visual Basic for Applications (VBA) and various Microsoft Office versions. The application fails to properly validate the path when loading external libraries, allowing it to load a malicious DLL from the current working directory instead of the intended system directory. An attacker can exploit this by placing a Trojan horse DLL in the same directory as a legitimate Office document (e.g., a .docx file) and convincing a user to open it. Successful exploitation allows the attacker to execute arbitrary code with the privileges of the logged-in user. This vulnerability was notably exploited in the wild starting in 2012.
Affected products
- Microsoft Office 2003 SP3
- Microsoft Office 2007 SP2 and SP3
- Microsoft Office 2010 Gold and SP1
- Microsoft Visual Basic for Applications (VBA)
- Microsoft Summit Visual Basic for Applications SDK
Timeline
- 2012-07: exploited: First reported exploitation in the wild.
- 2012-07-10: advisory: Microsoft released security bulletin MS12-046.
- 2026-04-13: kev added: Added to CISA Known Exploited Vulnerabilities catalog.