Russian anti-virus company Doctor Web is reporting that adware for Mac OS X has been increasing in number since the beginning of 2013.

Trojan.Yontoo.1 is the most prominent of them. It can download and install an adware browser plugin in an infected system, according to Dr. Web (http://tinyurl.com/c87upvm).

According to the company’s analysts, the trend towards a growing number of adware for various platforms has persisted from early 2013. Criminals profit from affiliate ad network programs, and their interest in users of Macs “grows day by day.”