How Spammers Fool Whitelists - And How to Stop Them

Effectively stopping spam over the long-term requires much more than blocking individual IP addresses and creating rules based on keywords that spammers typically use. The increasing sophistication of spam tools coupled with the increasing number of spammers in the wild has created a hyper-evolution in the variety and volume of spam. The old ways of blocking the bad guys just don't work anymore.

Examining spam and spam-blocking technology can illuminate how this evolution is taking place and what can be done to combat spam and reclaim e-mail as the efficient, effective communication tool it was intended to be.

One method used to combat spam is whitelisting. Whitelists are databases of trusted email sources. The list may contain specific email addresses, IP addresses or trusted domains. Emails received from a whitelisted source are allowed to pass through the system to the user's email box. The list is built when users and email administrators manually add trusted sources to the whitelist. Once built, the catch-rate for spam can be close to 100%, however, whitelists produce an inordinate number of false positives.

It is virtually impossible to produce an exhaustive list of all possible legitimate email senders because legitimate email can come from any number of sources. To get around this difficulty, some organizations have instituted a challenge-response methodology. When an unknown sender sends an email to a user's account, the system automatically sends a challenge back to the sender. Some challenge-response systems require the sender to read and decipher an image containing letters and numbers. The image is designed to be unreadable by a machine, but easily recognizable by a human. Spammers would not spend the time required to go through a large number of challenge-response emails, so they drop the address and move on to those users who don't use such a system.

Whitelists are only partially successful and impractical for many users. For example, problems can arise when users register for online newsletters, order products online or register for online services. If the user does not remember to add the new email source to their whitelist, or if the domain or IP address is entered incorrectly, the communication will fail. Additionally, whitelists impose barriers to legitimate email communication and are viewed by some as just plain rude.

Whitelists are not widely used by email users and administrators as a primary tool to fight spam because of the high number of false positives, and the difficulties in creating a comprehensive list of email sources. Because whitelists are not widely used, spammers typically do not develop countermeasures. As with other spam fighting techniques, whitelists are most effective when used in conjunction with other anti-spam tools.

The Solution

When used individually, each anti-spam technique has been systematically overcome by spammers. Grandiose plans to rid the world of spam, such as charging a penny for each e-mail received or forcing servers to solve mathematical problems before delivering e-mail, have been proposed with few results. These schemes are not realistic and would require a large percentage of the population to adopt the same anti-spam method in order to be effective. You can learn more about the fight against spam by visiting our website at www.ciphertrust.com and downloading our whitepapers.

Dr. Paul Judge is a noted scholar and entrepreneur. He is Chief Technology Officer at CipherTrust, the industry's largest provider of enterprise email security. The company's flagship product, IronMail provides a best of breed enterprise anti spam solution designed to stop spam, phishing attacks and other email-based threats. Learn more by visiting http://www.ciphertrust.com/prod ucts/spam_and_fraud_protection today.

---

Managing Spam in 2005

In 1998, nearly 10% of all email traffic on the... Read More

Internet Theft and Fraud

My friends in the web hosting business have recently informed... Read More

Is Spam Affecting Your Business Email?

5 Ways Spam Is Affecting Your Business And what we... Read More

The 4 Ws of Junk E-mail

Junk e-mail or spam has become the scourge of the... Read More

The Business Of Sending Spam

You all tear your hair out in frustration every time... Read More

How To Stop Spam (Especially If You?re Already a Victim)

Spam. Those annoying, time-consuming emails that clog your Inbox and... Read More

Avoiding the Spam Trap: Get Your Message Delivered!

Your message is not being delivered.If you send emails to... Read More

Do You Know Whats in Your Trash?

A hearty welcome to all the spam fighting filters and... Read More

Spam: The Tasteless Internet Meat of Criminals

Spam. You've all heard of the crazy pink meat in... Read More

Stop Spam: How To Escape The Spam Hell-Hole

If you're anything like me, you're pretty sick of it,... Read More

Get Your News Releases Through the Spam Filters in 11 Easy Steps

In today's spam-filled email world, it's sometimes VERY difficult to... Read More

How To Stop Unwanted Email Spam

You can stop unwanted email spam, you can choose to... Read More

Spammer Stole My Email Address?

Do you get bounced, or rejected emails sent by someone... Read More

Spam - Its Whats For Breakfast

The first thing I do every morning when I wake... Read More

Bayesian Spam Filters Explained

In a word Bayesian spam filters are "intelligent". Bayesian spam... Read More

Evict the Spammers from Your Inbox

Block Spam and Other Email Threats From Entering Your Gateway... Read More

Invasion of the Email Snatchers

They're sneaky. And stealthy. They're quiet and mostly unobtrusive, but... Read More

Email Chain Letters - Harmless Fun or Not?

I'm sure I'm not the only person on the planet... Read More

Block Ads, Defeat Pop-Ups, and STOP Page Hijacking

You're not alone!Who hasn't surfed the web looking for information... Read More

How Spammers Fool Bayesian Filters - And How to Stop Them

Effectively stopping spam over the long-term requires much more than... Read More

Anti Trackback and Comment Spam Methods

What is spam ? ... Read More

What To Do When You Get Spam

When you go to your mailbox and find pieces of... Read More

Protecting Yourself With A Porn Filter

The harmful affects of pornography use and addiction are well... Read More

FTC Botches Fight on SPAM, Microsoft Takes Over the Battle

While the Federal Trade Commission is busy fighting over definitions... Read More

BUSTED: Anti Spam Forces Bankrupt Super-Spammer Scott Richter

Microsoft scores one for the good guysScott Richter, the self-proclaimed... Read More

Pst... Pass It On... I Found Out Its a Hoax

When you receive an email telling you about a virus,... Read More

How To Identify Spam

Most of us have opened our email program and found,... Read More

Edating Readers

One of our Australian clients sent out a campaign using... Read More

What Exactly is Spam?

Spam, as defined in the context of computers, the Internet... Read More

How to Avoid Spam Complaints in Your Emails

Spam filters are responsible for deleting a high percentage of... Read More

The War on Spam: Google Fights Back

Google is engaged in a war. It is a war... Read More

Do Not Spam

The temptation among internet marketers to SPAM is greater than... Read More

Stop Spam! New Spam Blockers

News last week that Internet service provider Verizon settled its... Read More