It appears that the fall in the activity of spamming botnets may have just been a rather extended year-end holiday. Our information indicates that spam activity has returned to pre-holiday levels:
The spam runs we saw consisted of pharmacy-related messages that were not seen over the holidays:
Looking at longer-term patterns, overall spam volume on a monthly basis fell by about 40 percent compared with its peak in October 2010. In fact, the overall spam volume has been declining since that time, going back to levels last seen in February 2010.
A breakdown of the data by country shows the same pattern.
There are several possible causes for this decline, including the following:
- The activity of the Rustock spam-sending botnet has recently declined. Because Rustock sent as much as half of all the spam, any decline in its activity produces noticeable results.
- The ripple effect of the Spamit takedown may also be a contributing factor. Trend Micro has been closely collaborating with ISPs/MSPs all over the world and, according to our partners, these activities have been significantly reduced since the takedown in mid-October.
Despite any temporary decline, however, on a year-over-year basis, the number of spam still grew in 2010 compared with 2009.
We will continue to monitor the spam levels while protecting our product users from all kinds of spam threat. More information and analysis on these will be provided as part of our 2010 annual report.