While the total volume of spam emails fell in September to less than 11 billion messages, a three percent decrease from the previous month, more advanced spam and malware led to more focused and effective campaigns.

AppRiver reported that the most notable phishing campaigns featured the US Presidential election, Hurricanes Gustav, Hannah, and Ike, and a fictitious nuclear meltdown in Canada. These attention-grabbing stories link to video that redirects them via embedded in Flash (.swf) files hosted on legitimate domains in order to direct victims to their spam sites.

First discovered in January 2007, a Storm Worm, a backdoor Trojan horse, made an appearance on September 16, offering PC users a chance to play a game designed for the Apple iPhone on their desktops called "Penguin Panic," infecting their computer with the Asprox botnet.

In analysing attachment spam by file type and frequency, AppRiver found that image spam, where the message text of the spam is presented as a picture, has been gaining popularity over the past months. Image spam circumvents traditional spam filtering because it does not contain standard text and most email clients will render image files by default, presenting the message image directly to the user. September levels of image spam were more than one-and-a-half times higher than in the previous month.

The US, Turkey and Russia topped the top ten spam countries of origin list in September, and the UK returned to the top ten list, while the Republic of Korea made its first appearance in ninth position.

Spam originating in Asia fell nearly 10 percent from August. However, Europe's spam increased seven percent, making it the hottest spamming region and there were also increases in North America. Africa showed an explosion in spam transmission, jumping from 12.2 million messages in August to more than 300 million in September.