Spam is a form of email which is used to send to different email accounts and in general contains advertising about any product or services. But the real problem is when they contain malwares that can damage the user’s data.
Generally, they are sent to a massive list of emails for the mail purpose that a small percentage of users might open them and respond. They are used to such treatment because they are cheap in infrastructure investment, not too much time consuming and simple.
In this section, we will discuss the different techniques used by the spammers.
Domain Spoofing − The spammer sends an email on behalf of a known domain so the receivers think that they know this person and open it.
Poisoning Filters − A filter can be poisoned by adding text with the same color of the background to reduce the scoring of the filters.
Directory Harvesting − In directory harvesting, spammers generate email addresses by using known email addresses from corporates or ISP (Internet Service Provider).
Social Engineering − Spammers send promotional emails to different users such as offering huge discounts and tricking them to fill their personal data.
Junk Tags − Spam Words can be hidden by including invalid HTML tags within the words.
Invalid words − Special characters are inserted in the spam words. For example: V!AGRA.
In this section, we will discuss various anti-spam techniques and their advantages.
Signature Based Content Filtering − Most anti-spam email companies use this type of filtering because it checks the received email with certain patterns after saving the message to the disk.
Naive Bayes Spam Filtering − Bayesian filter scans the context of the e-mail when it looks for words or character strings that will identify the e-mail as spam.
Black Listing RBL − This is a type of database that updates the IP address and domains based on a reputation and the system administrators who use these RBL don’t receive email from domains that are blacklisted from this RBL.
Sender Policy Framework − The IP address of the domain of the sender is compared with the genuine list of the IP addresses that the domain should have and if it is not same, then that email is dropped.
In this section, we will discuss different anti-spamming tools and their benefits.
AEVITA Stop Spam Email − http://www.aevita.de/web/stopspam/
How it works − This tool will replace all your e-mail addresses on your page with specially encoded email addresses. The AEVITA Stop SPAM Email introduces codes that Spambots will "choke" on, but which a normal mailing program ignores. Therefore, people can still send you an email but spammers can't get your address!
Spam Experts Desktops https://www.spamexperts.com
How It Works − It works as a spam filter with any email program and automatically intercepts spam. It does depend on specific keywords to detect spam, but checks the content of a message whether to accept or reject it. It also checks for filtering spam in the background and also it maintains a list of blocked senders.
Spam Eater Pro − http://www.hms.com/spameater.asp
How It Works − It is also a spam email notification system, it reduces spam by 95%, it offers you a set of complex rules.
SpamWeasel − http://www.mailgate.com/
How It Works − It removes spam before it gets into the inbox. If it is suspected for spam but not sure, then it is stamped but not deleted. It supports POP accounts.
Antispam Sniper − http://antispamsniper.com/outlook-plugin.html
How It Works − AntispamSniper for Outlook provides professional antispam and antiphishing protection for your mailbox. A combination of several methods for automatic email classification results in an excellent filtering quality with the minimum error rate. The plug-in has a built-in option allowing deleting spam from the server by headers. The good messages deleted by mistake from server by header can be restored within a certain period of time after deletion. The plug-in filters POP3, IMAP and Exchange accounts.
Spam Reader − http://www.spam-reader.com/index.shtml
How It Works − Spam Reader is a free anti-spam add-on for Microsoft Outlook. The software uses the most reliable approach to block junk emails. The Bayesian Algorithm is based on statistical analysis, capable to be adjusted to user's needs and detect up to 98% of spam messages. The Spam Reader automatically scans all incoming mails and sends detected spam messages to the special folder for further review.
Mail Washer free − http://mailwasher.net/
How It Works − MailWasher is free to use and won't ever expire. It works with Outlook, Outlook Express, Incredimail, Thunderbird, Windows Mail, GMail, Hotmail and every other email program.