The spam is an electronic message that one never asked for and it’s being sent in an identical form to numerous receivers chosen randomly. The receiver is unable to find in these messages a possibility to choose to renounce receiving those messages from the same entity that sent them in the first place. The existence of the spam messages determined the emerging of the anti-spam software after the action-reaction model happening everywhere.
It seems that the origin of the term ‘spam’ is related to a funny situation connected to a sketch of a the British band Monty Python: In a restaurant, on all of the plates there is a food product called SPAM (coming from ‘Should of Pork and Ham’ – a sort of can), and whilst the waitress presents the menu to a couple of customers, a band sings in the background a song with its main lyrics being: ‘Spam, Spam, Lovely Spam’. The connection is that in the virtual or on-line environment, spam is represented, just like in that song, by an endless repetition of worthless texts.
Spam can mean both commercial publicity and non-commercial publicity. The commercial unwanted spam (also referred as UCE – Unsolicited Commercial E-mail) aims to increase the number of customers for that particular company. Often times, these messages are being sent by other people than the salesmen, people whom we call ‘spammers’ who receive a certain amount of money (commission) for this activity. Non-commercial spam usually consist of a certain type of religious, political or other kind of propaganda. For instance, the spammers often send fraudulent messages about people who are either ‘sick’ or ‘victims’ of some kind of catastrophes demanding financial help. In other situations, spammers let one know that they’ve won a certain lottery and demands that person to pay a service in order to claim the prize. A particular type of fraud committed by spammers is often referred as ‘phishing’ in which the victim receives a message that seems to come from a very prestigious company or firm demanding personal information (like bank accounts, passwords, etc.). There are also the so-called ‘Joe Jobs’ which in essence are spam messages with an offensive or vulgar content with the purpose of determining the receiver to reply with a cursing message to another person that is innocent and has no idea that he or she sent that message in the first place.
There are various ways through which the spammers get the e-mail addresses – they use databases they procure from companies, use software designed to get them or, more often, they use an on-line dictionary with which they combine letters, words and symbols thus generating valid e-mail addresses, or extract them from forums or interactive websites when users forget to hide their e-mail and leave it public, and so on and so forth.
The anti-spam filters work by combining various techniques to filter the messages and categorize them in authentic genuine messages and junk messages. These techniques usually use some or all of the following algorithms:
Word lists – which include those words that are most of the times found or associated with the junk mail and unsolicited e-mails.
‘Blacklists’ and ‘Whitelists’ – these are the lists that contain the IP addresses of the spammers and servers they use (blacklists) and the addresses of the people one knows and their family members (whitelists). The addresses that are part of your contact lists are automatically recorded as part of the whitelist – thus placing the e-mails that come from these addresses straight into you e-mail Inbox whilst the others’ e-mails need to pass through a sort of scrutiny.
Trend analysis – this consists in analyzing the e-mails an individual sends and establishing trends which help establishing the probability that a certain message is or is not a spam message. This technique can be highly efficient and reduces the rate of false-positive answers and also increases the detection rate of the junk messages.
Content filters (or learning filters). The learning filters, like the Bayesian type ones, are the filters examining the content of each e-mail. By learning the frequency of the words being used and the patterns associated with the junk and non-junk messages, these filters are capable to recognize the valid messages and implicitly direct them to Inbox, while the junk messages are being sent to the Spam or Junk folder.
The limitations of the anti-spam filters
Even though the most important protection software act upon your e-mail and protect you through ingenious and new filters, those who make a living from sending junk messages always find new modalities to work around the filtering techniques. Amongst the most used and the simplest ways is that of intentionally misspelling the words that are found in the blacklists. There is also a persisting problem with regards to the false-positive and false-negative answers provided by the anti-spam filters. In order to avoid the filters, the spammers have invented a new strategy – introducing into the e-mail’s title ‘Re:’ which functioned for a long period as the filter considered it a reply from a previously accepted e-mail.
Because of the fact that there is a possibility that a genuine e-mail be classified as spam and thus sent to the junk folder of the e-mail box, it is very important for the user to manually scan the received messages in order to avoid further inconveniences, albeit this is a process that takes some time.
Countless filtering software have been created since there was a high demand on this market segment because of the inconveniences that these kinds of messages can cause. Amongst the best known free software solutions for Windows 7/Vista/XP in this category we should mention: Norton Antispam (by Symantec Corporation), K9 Antispam (by Robin Keir), Zaep Antispam (by Rhino Software Inc.), Spam Experts, Spam Monitor (by PC Tools), Mailwasher, SpamPal, CA Anti-Spam (by CA Inc.), SPAMfighter, Pop3 Preview (by Pablo Software Solutions Inc. – This has only 80 KB – the smallest anti-spam filtering software), and so on and so forth.
However, just because these programs are free, it doesn’t mean they enjoy a lot of success as none of them is found amongst the most preferred solutions by the users, which are the following:
Kaspersky Internet Security (which is compatible with Windows XP/2k/NT/7/Vista) – is a multifunctional tool embedded into Kaspersky Antivirus and it ensures the protection of the defined e-mail boxes against spam messages, virus infected messages, various types of adware, spyware and identity theft and it also disables the hyperlinks that lead to untrustworthy websites containing malware.
Spam Bully is a plug-in available for Vista Mail, Outlook and Outlook Express and it stores the spam messages into a separate folder and realizes graphics by geographical area in order to tip the user about where these spam messages come from. The graphs are not so reliable since nowadays the spammers re-rout the messages through various servers around the world but Spam Bully’s filter is quite efficient for a Microsoft product.
BitDefender Total Security is amongst the best antivirus software but it’s also amongst the efficient anti-spam and antispyware solutions as well as in terms of firewall efficiency and real time scanning of the web and e-mail flow.
Eset Smart Security (based upon and part of the Eset Nod32 technology) offers anti-spam protection (both client-based and server-based), as well as the classical antivirus protection.
AVG Internet Security 2011 – is part of the AVG antivirus software with a multi-language interface. It has a reasonable efficiency in terms of anti-spam and anti-spyware and it also monitors in real time the e-mail flow including the Thunderbird and the MS Outlook clients. A plus for this product is that it also protects the user whilst he is making on-line transactions and it also blocks spam in ‘instant messaging’ clients.
Spamihilator is a web-browser plug-in compatible with Mozilla Firefox, Opera, Google Chrome, Netscape or Pegasus Mail (it doesn’t work on MS Internet Explorer though). This plug-in blocks the spam messages using the Bayesian filter, a learning filter, the Spam-Word-Filter, the Link Filter and the DDC-Filter. Its main advantage is that its efficiency rate can be constantly improved by the users’ behavior and the ability of the algorithm to adapt.
BitDefender (which is an antivirus technology and solution used by over 400 million users throughout the world) brought on this market segment for the year 2012 several anti-spam, antivirus, anti-fishing and other software meant for the protection of one’s computer whilst intensively using the Internet like: BitDefender Internet Security 2012, BitDefender Total Security 2012 or BitDefender Antivirus Plus 2012, all of them on reasonable prizes or with various promotions.
One of the most used and searched free software, particularly by those who intensely use the e-mail is the AVS Antispam software which is compatible with Windows 2000/7/Vista/XP but it has no equivalent version for Linux and Mac. Its excellent anti-spam protection is accomplished through several filters: First, there is the heuristic filter capable of verifying the foreign symbols repeated in a message’s content, to control whether the date is invalid or not, whether the mail has in its content some mentions with regards to prizes in money or whether the e-mail has any additional code that should not be there in a genuine e-mail. Second, there is the statistical filter which analyzes the probability that certain word from the message’s structure to be attributed to an unwanted sender and after these words’ occurrences the filter establishes whether that particular mail is a spam or not. The third filter controls whether the sender’s address is listed into the ‘blacklist’ or not, and the list can be made both by the server owner or updated by the anti-spam software. The fourth filter controls in real time the ‘black list of the spam-generating URLs’; of course, there is also a ‘white list’ of the viable users and the filter can make a decision based on the command ‘blacklist/whitelist’. All these commands (or options) are very simple given the friendly interface of the AVS Antispam software.
Statistical data compiled a year ago revealed that almost 90% from the total of the e-mail sent are spam e-mails. These e-mails, are not only illegal in most parts of the world, but they also provoke large expenses to the Internet service providers (of approximately 10 billion euros per year – or 13 billion US dollars) and, implicitly, to the internet users. They also mean a waste of time and productivity and the spam messages are also carrying viruses or obscene and offensive content and also dangerous for the inexperienced users.
This is why it’s necessary (almost imperative) to respect the minimum security measures at the individual level. The user should protect his or her e-mail address, so do not buy or use any service that is being advertised through spam messages, do not reply to any spam e-mails, make a separate ‘public’ e-mail address for forums, blogs, etc. and keep a strict confidentiality on your personal e-mail (give it only to the friends, acquaintances, personal contacts and work contacts); also do not provide your e-mail address if you are uncertain with regards to the purposes for which it will be used and, most important, always use an anti-spam solution!