USCERT: Active Exploitation Using Malicious Microsoft Access Databases

http://www.us-cert.gov/current/index.html#microsoft_access_database_file_attachment

US-CERT is aware of a stack buffer overflow vulnerability in the way that Microsoft Access handles specially crafted database files. Opening a specially crafted Microsoft Access Database (e.g., .MDB) can cause arbitrary code execution without requiring any additional user interaction. Microsoft Access files are considered to be high-risk, so it may be possible to execute arbitrary code without using a vulnerability in Microsoft Access.
US-CERT is aware of active exploitation using malicious Microsoft Access databases.
To help protect against this type of attack, US-CERT recommends the following:
Do not open attachments from unsolicited email messages
Block high-risk file attachments at email gateways