Spam
Glossary
Here you will find spam terms and other related definitions.
Address harvester
A program that searches web pages and filters newsgroup postings looking
for valid email addresses to be used for spam purposes. (See also harvesting.)
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Bayesian filtering
A statistical approach to determining whether an email is spam. Based on
probability inference techniques pioneered by English mathematician
Thomas Bayes.
Blackhole list
A publicised list, usually commercial, of IP addresses known to be
sources of spam. which can be used to create a network blacklist to
filter out mail originating from these addresses. (See also real-time
blackhole list.)
Blacklist
A feature of anti-spam software that allows users to designate IP
addresses, domain names and individual email addresses from which no
mail will be accepted. (See also Domain
Name System blackhole list.)
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Complex dictionary checking
A feature of anti-spam software that screens text for rude words and
isn't fooled by various spam tricks, such as the replacement of letters
with lookalike numerals or characters (such as "1nterest r@te").
CSS spam
Exploits Cascading Style Sheets (CSS), which are used to control the
display of web pages, in order to conceal messages in spam. Spammers can
also use CSS to recycle old HTML-based tricks which fool spam filters
that do not understand CSS.
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Denial of Service (DoS) attack
Where a hacker sends attachments or other unusual or excessive traffic
in an attempt to bring down email systems.
Dictionary attack
A program that bombards a mail server with millions of alphabetically
generated email addresses in the hope that some addresses will be
guessed correctly. This technique is also used to crack passwords.
Directory Harvest Attack (DHA)
When a spammer bombards a domain with thousands of generated email
addresses in an attempt to collect valid email addresses from an
organisation. (See also harvesting.)
Domain Name System blackhole list (DNSBL)
Commercial lists of networks that either allow spammers to use their
systems to send spam, or have not taken action to prevent spammers from
abusing their systems.
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False negative
When anti-spam software fails to identify a spam message as spam.
False positive
When anti-spam software wrongly identifies a legitimate message as spam.
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Greylist
Senders who are not blacklisted (excluded) or whitelisted (accepted) can
be placed on a greylist. Some anti-spam software can send greylisted
addresses an automated response, challenging the sender to confirm their
legitimacy.
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Hacker
Someone who intentionally breaches computer security, usually to cause
disruption or gain confidential information such as financial details.
Ham
All email that a recipient does not consider to be spam. (See also spam.)
Harvesting
The process of scanning the internet to identify email addresses in
order to create lists for spamming.
Honeypot
A computer system on the internet set up to attract and trap spammers
and hackers. Usually this is a mailserver set up to appear to be an open
relay.
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Listwashing
The process of removing email addresses from a mailing list at the
request of the recipients.
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Mail drop
An email address set up to receive email resulting from spam sent from a
different ISP. The spammer will cancel the account from which the spam
originated in an attempt to avoid detection.
Munging
A technique to protect email addresses from harvesting by changing them
and rendering them invalid. Recipients of an email from a 'munged'
address are told how to decode it, so that they can then reply to a
valid address. (See also obfuscation.)
Morph
A method that a spammer uses to avoid detection by anti-spam software
which involves modifying an email header.
Mousetrapping
A technique that page-jackers use, so that
users tricked into visiting an illegitimate site encounter only
additional, unwanted pages when they click the Back button to try to
escape.
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NDR spam
Uses a faked standard email non-delivery report (NDR) that a recipient
will think is genuine, tricking them into opening an attachment that is
spam. Spammers can send such an NDR directly or make a legitimate server
send it for them, adding to its credibility.
Network check (also known as reverse DNS check)
When an anti-spam engine uses a Domain Name System database to check an
email's IP address to ensure that it originated from a valid domain name
or web address.
Newsgroup
An electronic forum where readers post articles and follow-up messages
on specified topics. Often targetted by spammers seeking to harvest
email addresses.
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Obfuscation
Spammers' attempts to hide data to prevent its detection. Also, when
email recipients use HTML or Javascript to obscure mailto links and
email addresses so that addresses remain readable and clickable, but
cannot be harvested. (See also munging.)
Open relay
An SMTP email server that allows the third-party relay of email
messages. The relay feature is a part of all SMTP-based servers and it
has legitimate uses, but spammers have learned how to locate unprotected
servers and hijack them to send spam.
Opt-in
The process of agreeing to receive email from a business source. Double
opt-in refers to a double-check procedure in which a decision to be
included on a mailing list is confirmed.
Opt-out
The process of declining to receive email from a business source or
unsubscribing if the recipient is already on a mailing list.
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Page-jacking
This involves stealing the contents of a website by copying some of its
pages, placing them on a site that appears to be legitimate, and having
the contents indexed by major search engines, so that unsuspecting users
can be tricked into linking to the illegitimate site. (See also mousetrapping.)
Phishing
(Pronounced 'fishing'.) This involves creating a replica of a legitimate
web page to hook users and trick them into submitting personal or
financial information or passwords.
Phreaking
This involves illegally breaking into the telephone network to make free
long-distance phone calls or to tap phone lines. This term is also used
to include the act of breaching the security of any network.
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Real-time blackhole list (RBL)
This differs from a blackhole list in that
it actively boycotts TCP/IP addresses known to send spam or host
spammers. Enabling such a list results in all mail from those addresses
being refused, including valid email. This can, however, result in
innocent users complaining to their ISPs and those ISPs enacting
stronger anti-spam measures in order to get the RBL ban lifted.
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Social engineering
Conning email recipients into opening messages, revealing passwords or
providing other confidential information by appealing to their
curiosity, gullibility or computing naivety.
Spam
All unsolicited commercial email (UCE) and unsolicited bulk email (UBE)
that a recipient does not want to receive. (See also CSS
spam, NDR spam, and ham.)
Spambot
A program that spammers use to harvest email addresses from the
internet.
Spam trap
An option on an online form that is pre-selected by default, so that
unwary users opt-in to receive spam. It can also be used to refer to a
software filter that blocks email addresses known to send spam.
Spoofing
When spammers forge an email address to hide the origin of a spam
message. Email scammers and virus writers also use this trick. Scammers
spoof address lines to fool people into thinking an email has arrived
from a legitimate source, such as an online bank. Similarly, virus
writers have passed off viruses as security patches by spoofing their
origin as being, for example, from Microsoft technical support.
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Tarpitting
The use of traffic monitoring to identify remote IP addresses sending a
suspiciously large volume of email. Access to the mail system from
suspected spam addresses can then be slowed or temporarily suspended.
(See teergrube or tarpit.)
Teergrube (or tarpit)
An intentionally slow server that aims to trap spammers using harvesting
programs.
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Web bug
A small graphic inserted in an email or web page that alerts a spammer
when a message is read or previewed.
Whitelist
A list of external email addresses, IP addresses and domains trusted by
the entire organisation or individual users. All mail from these
addresses is delivered, bypassing the spam filters.
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Zombie
An insecure web server or computer that is hijacked and used in an DoS
attack or to send spam.
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