Danish software company SPAMfighter has created a unique type of filter to combat image spam.
SPAMfighter has been working at stopping image spam for a period of time and has come up with a filter for detecting this type of spam. The most recent image spam works by using multiple small images in e-mails advertising products such as stock shares and viagra. These images are too small for most spam filters to detect as spam, since they appear to be a legitimate e-mail and therefore cannot be detected. SPAMfighter's new filter works by gathering these multiple small images into one and filter based on this.
SPAMfighter is a community based spam filter. The SPAMfighter filter uses votes from this community to help determine if a mail is spam. With image spam, the small images are combined into one large image. The coding of this larger, single image is then scanned and the previously mentioned communitys votes are used to help determine if an e-mail is spam.
Many other spam filters are not able to do this, as they have no way of determining whether a graphic in an e-mail is spam, or a legitimate graphic being sent. Furthermore, these graphics are continuously being changed in color and size so that no two instances of an image spam mail are exactly identical.
The most recent version of SPAMfighter incorporates these new filter settings in place, allowing improved detection and filtering of image spam.
Related links: (Open in a new window.)
www.spamfighter.com/Default.asp
www.spamfighter.com/Download_Download.asp\
Taken from Information Security Bulletin.