All about AntiSpam Software

Bayesian filter: technology and advantages

Tip! G-Lock SpamCombat allows you assign the hot keys to the common operations. For example, you can assign F8 to Mark Message as SPAM function and F9 to Mark Message as Clean. Next time when you train the Bayesian filter you can simply use two keys on your keyboard F8 and F9.

Not a long time ago, most anti-spam products simply used a list of keywords to identify spam. A good set of keywords could catch much spam. However, a keyword-based anti-spam filter requires manual updating and can be easily fooled by tweaking the message a little. Spammers simply examine the latest anti-spam techniques and find ways to bypass them. At the result you’re left with a high number of false positives.

The need in a new effective technique to fight against spam stood up. The experience showed that this new method might adapt itself to the spammers' tactics that would change with time.

The Bayesian filtering is based on the principle that most events are dependent and that the probability of an event occurring in the future can be inferred from the occurrences of this event in the past. This approach is used to identify spam. If some piece of text occurred mostly in spam emails but not in legitimate mail, then it would be reasonable to suppose that this email is probably spam.

To filter mail using the Bayesian technology, you need to generate a database of words collected from spam and legitimate mail. Then a probability value is assigned to each word; the probability is based on the calculations that take into account how often that word occurs in spam as opposed to legitimate mail. After the legitimate and spam databases are created during an initial training period, the word probabilities can be calculated and the Bayesian filter is ready for use. When a new mail arrives, it is broken into words and the most significant words are singled out. From these words, the Bayesian filter calculates the probability of a new message being spam or not. If the probability is greater than a spam threshold, say 0.9, the message is classified as spam.

Keep reading ...

Spam scams: how not to become a victim

All spam emails we receive every day in tens or hundreds are annoying and disgusting. But the worst of them are scams, hoaxes, and illegal schemes aimed at defrauding you of your money, private information, and even your life. Being aware of how the spam scams work you will be able to protect yourself against the spammers-fraudsters and not to become a victim of their fraudulent schemes.

A lot of spam scams arrive in the form of a great investment offer. It usually works as a Pyramid scheme. Spammers ask you to pay money for a membership, goods, or simply to "invest" promising you much money as revenue. Your revenue will come from those people who will invest after you. Your investment is distributed to those who joined before you. At some point the pyramid ruins because there are not enough new investors to keep the money flowing. The spammer is at the top of the pyramid and he is the only one who benefits. The scan may not always look like an investment offer. The spammers can ask you to distribute some advertising letters to a list of email addresses, for remuneration. Although they will tell you that the list contains only opt-in email addresses, it’s not true, and you will be sending spam directly from your computer.

Keep reading ...

Image Spam And How To Fight It

Spam attacks where the text is replaced with images aimed at lightly protected email systems are growing in popularity. With the variety of anti-spam filters that analyze the message content to weed out unsolicited emails, spammers continue to increasingly adopt image spam. Businesses, organizations and everyday computer users might have noted an increase of image-based spam, text e-mails that arrive in your in-box as image files. Image spam can contain a picture of words, a screenshot, a photographic image, or a combination of these. By sending emails that contain no text, only pictures, spammers found that they can fool even the most advanced anti-spam software.

Types of spam using this technique:

Stock ads (fake stock tips)
Home Mortgage ads
Pharmacy ads

Most anti-spam programs detect text-based spam very well, but they totally fail when a spam message has no text to analyze. Thus, the rapid rise of the image spams. These spam messages often include image files that have a screen shot offering the same types of information advertised in more traditional text spam. Image spam can also include unique trackers which work when a recipient opens the message and let the sender know it's a valid email address, ripe for future mailings. Image spam is probably the best technique that spammers have today to get past the anti-spam filters. Together with the image spam that uses one attached image to deliver its message, the spammers are known to send spam that contains multiple images that act like pieces in a puzzle. The recipient's email client then reassembles the pieces in the right order and displays them as one image again. In addition to the usual annoyance, image-based spam eats up more bandwidth than regular spam because each image spam message is more than seven times larger than regular spam email - what's costing users, especially business, money.

Keep reading ...