Posted on Nov 26 2021
By iCurated
Spam Filtering: General Discussion
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11-26-2021 at 03:32 PM
What is spam?
A "spam" email is generally defined as an unsolicited mailing, usually to many people. A person unknown writes this message to you and sends it to your email address without your permission. In other words, it is the equivalent of receiving a postcard in the mail that advertises a company that you have never heard of; only unlike mail sent via USPS, spam does not cost the sender anything to deliver that message to your ‘mailbox.’
An email message sent to one individual that is known to the sender is not spam. A reply to an email is not spam unless the ‘reply’ repeats endlessly. Spam is also known as ‘UCE,’ or Unsolicited Commercial Email.
Where did the term 'spam' come from?
The term 'spam' was derived from a Monty Python skit in which several members in the background simply repeat the word 'spam' in an ever-increasing and annoying chorus that eventually drowns out the main skit.
The spam movement
'Spammers' are people who intentionally cultivate email addresses for the purpose of generating mass email solicitations. Spammers have their own culture and ethics. As a result of anti-spam measures taken by a majority of the internet community, spammers have responded to the threat by setting up their own Internet sites. These sites cater to and encourage spamming activity. Some companies cater specifically to spammers. One example is the internet service providers who intentionally minimizes email restrictions in order to support spam activity (this is referred to as a ‘bulk email friendly’ ISP). Internet sites are gradually splitting into two classes -- those that welcome spammers and have no normal users, and those that aggressively stop spamming from their sites to protect their legitimate users. If your ISP's mail servers are 'blocked' by other ISPs, it is because your ISP allows mass email activity on their servers. In any case, your ISP may not willingly condone the practice of spam - either they do not have safeguards in place to prevent spam activity, or a fellow subscriber abused his/her mail privileges to the detriment of everyone else. Bottom line? Look for an ISP who actively promotes anti-spam and/or fines users for spam activity. You'll thank us later.
CAN-SPAM Act of 2003
The good news in the battle against spam is the passage of the CAN-SPAM Act of 2003, which took effect January 1, 2004. This law makes the sending of spam illegal, and
Here are things you should know to combat the huge force of spam.
The biggest mistakes people make:
NEVER reply to a spam email message! This is even more important when the message you receive includes links such as ‘click here to unsubscribe’ or ‘remove my name from this mailing list.’ If you respond, that spammer knows that your address has a live person on the other end. Once they know they have a ‘live one’, they sell or distribute your name to other spammers – and the value of your email address just went up so you will be sold to other spammers. Bottom line: If you reply to spam, expect to see your inbox flooded with even more spam.
NEVER purchase an item from a spam email. For a spammer, one sale among thousands of mailings justifies the practice of spamming. Remember, this is a numbers game. It costs the spammer nothing to send the message to you, so if a few people purchase something from their email, it justifies the time it took to spam everyone. If you want a product that is advertised in a spam email, go to Google. Then, search for another website where you can purchase that item. Bottom line: Do not condone the practice of spam by buying from spammers.
NEVER give your email address to sites promising to take your name off spam lists. While the site author may genuinely want to help you, more likely they are spam address collectors. In any case, spammers exploit security holes in sites that collect email addresses. Once your address is recorded and validated (because you posted it there), it will be added to spam lists. Bottom line: There are better ways to combat spam than to sign up for exclusion lists.
NEVER send email to your friends via a mass mailing. In other words, most email programs allow you to ‘BCC:’ (stands for ‘blind carbon copy’) recipients, meaning that once sent, the email addresses of your recipients is hidden from one another. Here is why this is so important:
Jane Novice receives an interesting article and she emails it to all her friends -- but she does it by including all the addresses in the TO: field. The problem? Each recipient gets a copy of all addresses. Then, one of Jane’s friends forwards that
message (which includes the list of email addresses) to all of her friends. Over time, the address list becomes very large. Ultimately, it falls into the hands of someone in the spam trade.
Instead, Jane should mail a separate copy to each of her friends. Alternatively, she can also ‘BCC’ recipients. Bottom line: The easier you make it for spammers to collect multiple email addresses (especially in one place), the more likely you are to get blasted with spam.
NEVER attempt to battle spammers by engaging in hacking or mail-bomb activity. This will only increase the amount of extraneous Internet traffic and just creates sympathy for spammers. Please do not make the Internet even less reliable than it already is!
Smart spam avoidance:
Take meaningful action to stop spammers. Filter your inbox messages, write to spammer host sites (without revealing your real email address, of course!) to let them know that you do not support their activity, and write your congressional representatives. Effective legislation would likely impose meaningful fines to those who spam and make it riskier to engage in spamming.
Disguise all email addresses posted online. One surefire way to get on a spam list is to post your email address on a web page! Spammers harvest addresses using computer programs that are designed to collect addresses. If you must post your email address on a web page, it is useful to disguise the address. For example, instead of posting your email address as ‘[email protected],’ replace that with ‘yourname at domain dot com’ (spell out the ‘at’ and ‘dot’ in your address.) Most harvesting programs will skip right over your email address since they are designed to look for an email address with the @ sign in it. Smarter spammers will overcome this, but many are not that savvy (or they would choose a more legitimate career as a programmer).
Opt-out of member directories that may place your email address online. If your employer places your email address online, ask the Webmaster to make sure it is disguised in some way.
Use multiple email addresses. When visiting an unfamiliar website or posting to a newsgroup, establish an email address for that specific purpose. You can use 'alias' email addresses, which consolidate email in a single location but allow you to immediately shut off any address that is attracting spam. By recording which email address was used at each website, you can track which sites are causing your inbox to overfloweth with spam. You can search in Google for 'disposable email addresses' to find companies that provide disposable (or one-time use) email addresses. Also, you can sign up for a few free email accounts with Gmail (or old school ones likes Hotmail or Yahoo). Use those addresses instead of your permanent email address.
Use a filter. Quality ISPs provide advanced email filtering. Even some free email services now provide spam filtering. While filters are not perfect, they can cut down tremendously the amount of junk email that your account receives.
Newsgroups users beware! Newsgroups are a great email address gathering ground for spammers. If you post to a group, you are going to get spam -- it is just a matter of time. So how are you supposed to participate? Use a different email address than the one you use for talking to friends and relatives. In other words, have a 'public' address and a 'private' address. You’ll just have to deal with the spam in your public account.
Short email addresses are easy to guess, and often receive more spam. Email addresses composed of short names and/or initials like [email protected], or basic combinations like [email protected] receive more spam. Email addresses do not need to be incomprehensible, but modify or add to it in some way so that it is not so easy to target.
Some spam is generated through 'attacks' on mail servers, where spammers use software programs to send spam to every possible combination of letters at a domain. While these attacks are often caught by your ISP, you can imagine how hard it is for your ISP to immediately distinguish between all of the millions of email messages passing through their mail servers and those of a spammer. Some spam is likely to get through. In many cases, spam generated by these attacks will get through to shorter email address (like [email protected]) before it is directed to longer addresses. If your last name starts with a 'Z,' you will recall how often you were last when you were a kid in school. Sometimes, last is good.
Most spam is simply annoying, but some of it is illegal.
When you receive an email that asks you to send $1 to several addresses in the letter, and promises a windfall if you follow the letter's instructions, this represents a 'pyramid scheme' and it is illegal.
There are many other kinds of illegal email. For example, you have likely received the email that comes from a foreign (typically Nigerian) person who says they have a large sum of money on deposit at an exotic bank, and that they simply need your account number to send that money to you. For facilitating the transaction, it goes on to claim, they will let you keep a couple million dollars. Come on! Do you really believe this? This is called 4-1-9 (or '419 Fraud') Fraud, for the section in the Nigerian Penal Code that deals with this issue. Check with the Secret Service site if you do not believe us.
If you believe an email is fraudulent, you should report it. Here are some addresses that accept fraud reports:
To report spam violators (by email). Use the link to send an email to: uce at ftc.gov.
The Federal Trade Commission Home Page (http://www.ftc.gov)
The Internet Fraud Watch/National Fraud Information Center (http://www.fraud.org)
What does the garbled text mean?
If you receive spam email with strange or unintelligible writing in it, or strange text in the subject line, it is probably spam - written in a foreign language. When your computer does not know how to translate the text, it comes through as a string of meaningless letters and/or numbers.
Much of the total output of spam comes from overseas servers, where spam regulations are lax. As a result, many US-based ISPs have blocked many servers located in specific countries. If you have difficulty receiving mail from a legitimate contact in another country, you will likely find that your mail server has been set up to block incoming email from that person(s). You will then need to contact your ISP to report the difficulty and see if they are comfortable unblocking their mail servers so that you can receive mail from him/her.
How do filters work?
Quality ISPs put spam filters on their mail servers, but you can further guard against spam by using a spam filtering program on your computer. These spam programs vary greatly, but their basic function is to allow you to enter non-allowable keywords and 'quarantine' all messages containing those spam keywords into a separate inbox.
Spammers like to sell things that sound as if they might be hard to get, illegal, or sexy. Words and phrases that are common in spam email include terms such as: Viagra, credit repair, college degree, free trial, enter, sexy, hot, enlargement, etc., Although you will feel stupid typing nasty words into the spam filter program, unless you regularly use these words in your communications with friends and colleagues, you will stop a lot of unsavory and pornographic spam email. This is especially important if you have children using the same computer. (Or, if you have the option to turn ON children settings, use them to automatically filter your communications but be sure to read those details so that you do not miss an important email).
The things your spam filters need to look for will be determined by the nature of the spam you receive. You also want to consider the likely content of the legitimate email you receive, and make sure your spam filters do not mistake any of it for spam.
Most spam filters can be set up to perform a variety of actions when it identifies an incoming message that has the qualities of spam. Among the choices are to send a reply to the spammer with a canned message that informs them that their message was deleted automatically. However, few spammers use a genuine return address, so in most cases your message will be returned a few hours later, necessitating that you delete it manually. It is more hassle than satisfaction.
Spam filters can also deposit spam directly to your Trash box, where it will be deleted automatically. However, this risks sending legitimate email into the trash without being read.
Ideally, you will have a spam filtering program that allows you to create a 'quarantine' folder and have your spam sent to it. This way, you can scan through your quarantined mail from time to time to see if it contains anything important.
Bottom line: Creating and maintaining a spam mail filter requires a fair amount of effort, although over time you will likely spend a heck of a lot more time filtering through spam manually.
What is a blackhole list?
A blackhole list, often referred to as a blacklist, is a list of ISP addresses known to be sources of spam. The primary goal of a blackhole list is to provide a list of IP addresses that a network can use to filter out undesireable traffic. After filtering, traffic coming or going to an IP address on the list simply disappears, as if it were swallowed by a black hole. The Mail Abuse Prevention System (MAPS) Real-time Blackhole List (RBL), is one of the most popular blackhole lists. Other popular blackhole lists include the Relay Spam Stopper and the Dialup User List.