Mark Twain once said, "It's not the size of the dog in the fight, it's the size of the fight in the dog.” And, this idea also seems important when considering image spammers. While image spam has not yet regained the dizzying heights of 2007—when 52% of all spam was image spam—in the last seven days, image spam has hit an average of seven percent of all spam messages. As image spam struggles to find its feet within the overall composition of spam messages, another image spam vector has emerged. By analyzing image spam recorded in the last seven days, Symantec notes that over this period:
• 9.7% of image spam had a message size greater than 100kb• 48% of image spam had an average size of between 10kb-50kb
In the last 24 hours alone, 28% of image spam had an average message size greater than 100kb:
When you consider spam messages in total for the last 30 days, only six percent fall into the 10kb+ range, with the majority (78%) of messages falling into the 2kb-5kb range. Large message size can put inordinate strains on mail infrastructures and could possibly prevent end users from receiving legitimate email. If image spam continues to fight for its position within the "spamscape" it could indicate trouble for unprotected mail infrastructures. The good news is that Symantec antispam effectiveness is not being negatively impacted due to this trend.