The Microsoft Security Intelligence Report (SIR) provides an in-depth perspective on the changing threat landscape including software vulnerability disclosures and exploits, malicious software (malware), and potentially unwanted software. Each individual report focuses on data and trends observed in either the first or second half of each calendar year and uses historical data to provide context. The purpose of the SIR is to keep Microsoft’s customers informed of the major trends in the threat landscape and to provide valuable insights and security guidance designed to help customers improve their security posture in the face of these threats.

SIR Volume 3 (January through June 2007) and Key Findings Summary:
http://go.microsoft.com/fwlink/?LinkID=103122&clcid=0x409

Urs