Microsoft has announced the publication of the thirteenth volume of its Security Intelligence Report, a biennial report that provides a detailed overview of the trends in malware in the first half of 2012.

One of the major changes in the last six months has been the growth in the number of key generators that are directly related to the spread of malware. The software giant found that the family Win32/Keygen, representing such threats, was the most common between January and June 2012, with about 5 million studio appearances by Microsoft.

These key generators are utilities that users exploit to hack all sorts of games and applications, allowing to obtain valid keys to get full access to the functionality of the software. According to Microsoft, these generators often include malware.

In fact, in their study found that 76% of the computers that detected the existence of key generators also detected several malware families. Still, this is far from being the only source of malware, and Microsoft also warned of the use of legal theory downloads (such as Adobe Flash, widely used by cybercriminals) to distribute malware.