Spam - An Introduction

Unless the problem of Spamming is contained, it can destroy the use of email as an effective communication tool. Sadly, sufficient number of recipients respond to spam messages making the practice of sending spam worthwhile for spammers.

A spam is an Unsolicited Commercial Email (UCE) which is also known as junk mail. Spamming is generally done by commercial, mostly unscrupulous, operators who view the Internet purely as a way to sell products and services. They resort to spamming because it is the cheapest way to send thousands of mails at a time. But it has become the most critical problem for messaging and network administrators today.

Spam could be in the following forms: Chain letters, Multi Level Marketing or MLM, other "Get Rich Quick" or "Make Money Fast" (MMF) schemes, offers of phone sex lines and ads for pornographic web sites, offers of software for collecting e-mail addresses and sending UCE, offers of bulk e-mailing services, stock offerings for unknown start-up corporations, drugs, health products and remedies, illegally pirated software. Why is Spam such a problem? As the cost of sending bulk emails is extremely cheap, spammers use freely available bulk email software to send hundreds of thousands of messages per hour.

Removing spam is not as simple as deleting it. Mail servers are busy delivering mails. If the ISP starts filtering, the mail server gets even busier. The ISP spends on buying powerful servers or more number of servers to avoid delay in delivery of mails. Also, the ISP spends bandwidth in delivering the mails. The ISP passes on the cost to the subscriber. So ultimately the recipients are forced to bear costs that the advertiser has avoided.

There are so many ways that spammers try to reach their mail into your inbox. One is trying to make the subject look like as if it is a genuine mail. Spammers also deliberately make spelling mistakes in the subject and body to make their mail go past filters that the ISP or the user may have set. Another common ploy is to find an 'open relay' to push the mail through. An open relay is a mail server which has not been setup properly and allows anyone to send a mail through it without proper authentication. This tactic doubles the damages: both the receiving system and the innocent relay system are flooded with junk mails. And for any mail that gets through, often the flood of complaints goes back to the innocent site because they were made to look like the origin of the spam. Additionally, spammers try to forge the headers of messages, making it appear as though the message originated elsewhere, again providing a convenient target.

At Sify, around 60% of mails are found to be spam. These are filtered using Bayesian spam filters with powerful servers which break each and every mail into words and calculate the probability of a word being spam. This is done by comparing a huge dictionary of Spam and Non-Spam words. It is a tremendous burden shifted to the ISP to process and store that amount of data. Volumes like that may undoubtedly contribute to access, speed, and reliability problems. Indeed, many large ISPs have suffered major system outages as a result of massive junk email campaigns. Unless this problem is contained, Spam can destroy the use of email as an effective communication tool.

Unfortunately, sufficient number of recipients respond to spam messages making the practice of sending spam worthwhile for spammers, who have become sophisticated using techniques like filtering and approaches like real-time blacklists ineffective against spam.

Author: Manvendra Bhangui