Email spam
Email spam, also referred to as junk email, spam mail, or simply spam, refers to unsolicited messages sent in bulk via email. The term originates from a Monty Python sketch, where the name of a canned meat product, "Spam," is used repetitively, mirroring the intrusive nature of unwanted emails. Since the early 1990s, spam has grown significantly, with estimates suggesting that by 2014, it comprised around 90% of all global email traffic.
Spam is a burden for the recipient, who may be required to manage, filter, or delete these unwanted messages. This cost imposed on recipients, without compensation from the sender, makes spam an example of a "negative externality".
The legal definition and status of spam varies from one jurisdiction to another, but laws and lawsuits have not generally been successful in stemming spam.
Most email spam messages are commercial in nature. Whether commercial or not, many are not only annoying as a form of attention theft, but also dangerous because they may contain links that lead to phishing web sites or sites that are hosting malware or include malware as file attachments.
Spammers collect email addresses from chat rooms, websites, customer lists, newsgroups, and viruses that harvest users' address books. These collected email addresses are sometimes also sold to other spammers.
Overview
At the beginning of the Internet, sending of commercial email was prohibited. Gary Thuerk sent the first email spam message in 1978 to 600 people. He was reprimanded and told not to do it again. Now the ban on spam is enforced by the Terms of Service/Acceptable Use Policy of internet service providers and peer pressure.Spam is sent by both otherwise reputable organizations and lesser companies. When spam is sent by otherwise reputable companies it is sometimes referred to as Mainsleaze. Mainsleaze makes up approximately 3% of the spam sent over the internet.
Spamvertised sites
Many spam emails contain URLs to a website or websites. According to a Cyberoam report in 2014, there are an average of 54 billion spam messages sent every day. "Pharmaceutical products jumped up 45% from last quarter's analysis, leading this quarter's spam pack. Emails purporting to offer jobs with fast, easy cash come in at number two, accounting for approximately 15% of all spam email. And, rounding off at number three are spam emails about diet products, accounting for approximately 1%."Spam is also a medium for fraudsters to scam users into entering personal information on fake Web sites using emails forged to look like they are from banks or other organizations, such as PayPal. This is known as phishing. Targeted phishing, where known information about the recipient is used to create forged emails, is known as spear-phishing.
Spam techniques
Appending
If a marketer has one database containing names, addresses, and telephone numbers of customers, they can pay to have their database matched against an external database containing email addresses. The company then has the means to send email to people who have not requested email, which may include people who have deliberately withheld their email address.Image spam
, or image-based spam, is an obfuscation method by which text of the message is stored as a GIF or JPEG image and displayed in the email. This prevents text-based spam filters from detecting and blocking spam messages. Image spam was reportedly used in the mid-2000s to advertise "pump and dump" stocks.Often, image spam contains nonsensical, computer-generated text which simply annoys the reader. However, new technology in some programs tries to read the images by attempting to find text in these images. These programs are not very accurate, and sometimes filter out innocent images of products, such as a box that has words on it.
A newer technique, however, is to use an animated GIF image that does not contain clear text in its initial frame, or to contort the shapes of letters in the image to avoid detection by optical character recognition tools.
Blank spam
Blank spam is spam lacking a payload advertisement. Often the message body is missing altogether, as well as the subject line. Still, it fits the definition of spam because of its nature as bulk and unsolicited email.Blank spam may be originated in different ways, either intentional or unintentionally:
- Blank spam can have been sent in a directory harvest attack, a form of dictionary attack for gathering valid addresses from an email service provider. Since the goal in such an attack is to use the bounces to separate invalid addresses from the valid ones, spammers may dispense with most elements of the header and the entire message body, and still accomplish their goals.
- Blank spam may also occur when a spammer forgets or otherwise fails to add the payload when they set up the spam run.
- Often blank spam headers appear truncated, suggesting that computer glitches, such as software bugs or other may have contributed to this problem—from poorly written spam software to malfunctioning relay servers, or any problems that may truncate header lines from the message body.
- Some spam may appear to be blank when in fact it is not. An example of this is the VBS.Davinia.B email worm which propagates through messages that have no subject line and appears blank, when in fact it uses HTML code to download other files.
Backscatter spam
If the sender's address was forged, then the bounce may go to an innocent party. Since these messages were not solicited by the recipients, are substantially similar to each other, and are delivered in bulk quantities, they qualify as unsolicited bulk email or spam. As such, systems that generate email backscatter can end up being listed on various DNSBLs and be in violation of internet service providers' Terms of Service.
Legal countermeasures
If an individual or organisation can identify harm done to them by spam, and identify who sent it; then they may be able to sue for a legal remedy, e.g. on the basis of trespass to chattels. A number of large civil settlements have been won in this way, although others have been mostly unsuccessful in collecting damages.Criminal prosecution of spammers under fraud or computer crime statutes is also common, particularly if they illegally accessed other computers to create botnets, or the emails were phishing or other forms of criminal fraud.
Finally, in most countries specific legislation is in place to make certain forms of spamming a criminal offence, as outlined below:
European Union
Article 13 of the European Union Directive on Privacy and Electronic Communications provides that the EU member states shall take appropriate measures to ensure that unsolicited communications for the purposes of direct marketing are not allowed either without the consent of the subscribers concerned or in respect of subscribers who do not wish to receive these communications, the choice between these options to be determined by national legislation.United Kingdom
In the United Kingdom, for example, unsolicited emails cannot be sent to an individual subscriber unless prior permission has been obtained or unless there is a pre-existing commercial relationship between the parties.Canada
The 2010 Fighting Internet and Wireless Spam Act is Canadian legislation meant to fight spam.Australia
The Spam Act 2003, which covers some types of email and phone spam. Penalties are up to 10,000 penalty units, or 2,000 penalty units for a person other than a body corporate.United States
In the United States, many states enacted anti-spam laws during the late 1990s and early 2000s. All of these were subsequently superseded by the CAN-SPAM Act of 2003, which was in many cases less restrictive. CAN-SPAM also preempted any further state legislation, but it left related laws not specific to e-mail intact. Courts have ruled that spam can constitute, for example, trespass to chattels.Bulk commercial email does not violate CAN-SPAM, provided that it meets certain criteria, such as a truthful subject line, no forged information in the headers. If it fails to comply with any of these requirements it is illegal. Those opposing spam greeted the new law with dismay and disappointment, almost immediately dubbing it the "You Can Spam" Act.
In practice, it had a little positive impact. In 2004, less than one percent of spam complied with CAN-SPAM, although a 2005 review by the Federal Trade Commission claimed that the amount of sexually explicit spam had significantly decreased since 2003 and the total volume had begun to level off. Many other observers viewed it as having failed, although there have been several high-profile prosecutions.
Deception and fraud
Spammers may engage in deliberate fraud to send out their messages. Spammers often use false names, addresses, phone numbers, and other contact information to set up "disposable" accounts at various Internet service providers. They also often use falsified or stolen credit card numbers to pay for these accounts. This allows them to move quickly from one account to the next as the host ISPs discover and shut down each one.Senders may go to great lengths to conceal the origin of their messages. Large companies may hire another firm to send their messages so that complaints or blocking of email falls on a third party. Others engage in spoofing of email addresses. The email protocol has no authentication by default, so the spammer can pretend to originate a message apparently from any email address. To prevent this, some ISPs and domains require the use of SMTP-AUTH, allowing positive identification of the specific account from which an email originates.
Senders cannot completely spoof email delivery chains, since the receiving mailserver records the actual connection from the last mailserver's IP address. To counter this, some spammers forge additional delivery headers to make it appear as if the email had previously traversed many legitimate servers.
Spoofing can have serious consequences for legitimate email users. Not only can their email inboxes get clogged up with "undeliverable" emails in addition to volumes of spam, but they can mistakenly be identified as a spammer. Not only may they receive irate email from spam victims, but a naïve ISP may terminate their service for spamming.