How Spammers Fool Spam Blacklists - 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 blacklisting. The goal of blacklisting is to force Internet Service Providers (ISPs) to crack-down on customers who send spam. A blacklisted ISP is blocked from sending email to organizations. When an ISP is blacklisted, they are provided with a list of actions they must take in order to be removed from the blacklist. This controversial method blocks not just the spammers, but all of the ISP's customers. Blacklisting is generally considered an unfriendly approach to stopping spam because the users most affected by the blacklist are email users who do not send spam. Many argue blacklisting actually damages the utility of email more than it helps stop spam since the potential for blocking legitimate email is so high.

In addition to the ethical considerations, there are other problems with blacklists. Many blacklists are not updated frequently enough to maintain effectiveness. Some blacklist administrators are irresponsible in that they immediately block suspect servers without thoroughly investigating complaints or giving the ISP time to respond. Another downside is that blacklists are not accurate enough to catch all spam. Only about half of servers used by spammers, regardless of how diligent the blacklist administrator may be, are ever cataloged in a given blacklist.

Blacklists are used because they can be partially effective against spammers who repeatedly use the same ISP or email account to send spam. However, because spammers often change ISPs, re-route email and hijack legitimate servers, the spammer is a moving target. Blacklist administrators are forced to constantly revise lists, and the lag-time between when a spammer begins using a given server and when the blacklist administrator is able to identify the new spam source and add it to the blacklist allows spammers to send hundreds of millions of emails. Spammers consider this constant state of flux a part of doing business and are constantly looking for new servers to send spam messages.

When used individually, each anti-spam technique has been systematically overcome by spammers. Blacklists have some utility in stopping known spammers, but they may also block valid emails. Because of their limitations, blacklist data should only be used in conjunction with other sources to determine if a given message is spam. 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.

The Solution

Reputation systems offer a comprehensive anti spam solution by dynamically updating black and whitelists based on sender behavior. These systems also automatically update and score messages thereby removing the burden from administrators. Today's spammers are more clever than ever, so today's reputation systems must be equally sophisticated. An effective reputation system must be dynamic, comprehensive, precise, and based on actual enterprise mail traffic in order to keep the spammers from gaining any advantage. 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.

---

The Fastest Delete Finger in the Midwest!

There are hundreds of thousands of people who are trying... Read More

Fight Spam and Fortify Your Web Site with RSS

RSS is the answer to the Spam epidemic of the... Read More

Internet Theft and Fraud

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

A Practical Approach to Eliminate Spam

Spam is out of control! I guess that would be... Read More

Kill The Messenger (Service)

You are familiar with the software applications that you run... Read More

Is Your Website Blacklisted?

A blacklist, as the name implies, is a list of... Read More

Dont Give the Spammers Your Address From Your Page

Spammers get email addresses from web pages using programs called... Read More

Managing Spam in 2005

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

The Business Of Sending Spam

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

Im Guilty Until Proven Innocent

No doubt about it."Spam" (unsolicited commercial email) threatens to paralyze... Read More

Corporate Email Policies Lower Unnecessary Legal and Security Risks

What comes to your mind when you think about your... Read More

How Spammers Fool Spam Blacklists - And How to Stop Them

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

Spam: The Tasteless Internet Meat of Criminals

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

Your Dolphin E-mail Caught In Spam Tuna Net?

Let me ask a couple of questions:If (potential) customers sends... Read More

Anti Trackback and Comment Spam Methods

What is spam ? ... Read More

CAN-SPAM Basics

I. BACKGROUNDThe CAN-SPAM Act of 2003 (Controlling the Assault of... Read More

How Can I Stop Getting Spam?

Are you getting too much spam? We all are, but... Read More

How Spammers Fool Rule-based and Signature-Based Spam Filters

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

Challenge Response Spam Filters Explained

As the flood of spam increases end users are looking... Read More

Why Is Spam Such a Problem?

Spam can be a lot more damaging than you might... Read More

Internet Tip of the Week: Cease and Desist

While we all admit that unsolicited commercial email is a... Read More

Getting Back To Basics.

While we all agree that there`s way too much spamming/junk-mailing... Read More

Spamicide: Man Spammed to Death While Checking His E-mail

Death by spam is now possible with a new device... Read More

What To Do When You Get Spam

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

Invasion of the Email Snatchers

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

Sick Of Wading Through Spam?

It's a nightmare isn't it? You fire up your email... Read More

Demand for Spam? It exists

Do you like spam? No, I'm not kidding. Everybody knows... Read More

Stop Intrusive Pop-up Ads and Regain Control of Your Online Experience!

Stop intrusive pop-up ads and regain control of your online... Read More

Email Chain Letters - Harmless Fun or Not?

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

Eight Quick Tips For Stopping SPAM

If you are buried in SPAM then you're not alone.... Read More

The War on Spam: Google Fights Back

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