Although spam levels remain at a relatively low volume following the takedown of the spam host McColo last week, there is some evidence that spammers are starting to prepare for a rally. Late last week we observed the spam volume spike as much as 150% in an hour-to-hour comparison, which is about a seven percent increase since McColo was shut down.
In addition to overall spam volumes, the percentage of spam messages containing the text/HTML content type mime part jumped to 55% of all spam, indicating a change in the overall makeup of spam. Prior to the McColo takedown, the overall percentage of spam messages containing the text/HTML content type mime part was over 55%, but after the takedown the average has been around 34%. This change indicates that a return to normal spam activity could be in the works.
When we took a closer look at the spam contained in the spikes, it was revealed that there was an increased use of HTML. The spam messages were typical “...