Log in as root (or you can use sudo) and open /etc/drweb/drweb32.ini:

Look for:
CronSummary = Yes

And change it to:
CronSummary = No

Do a restart for the Dr. Web daemon by (add sudo in the beginning if not using root):
/etc/init.d/drwebd restart

I found this solution on this site.

http://adeelejaz.com/blog/stop-dr-web-antivirus-update-emails/