Spambot
Encyclopedia
A spambot is an automated computer program
designed to assist in the sending of spam
. Spambots usually create fake accounts and send spam using them, although it would be obvious that a spambot is sending it. Some spambots, however, can crack passwords and send spam using other people's accounts.
addresses from material found on the Internet
in order to build mailing lists for sending unsolicited e-mail, also known as spam
. Such spambots are web crawler
s that can gather e-mail addresses from Web sites, newsgroups, special-interest group (SIG) postings, and chat-room conversations. Because e-mail addresses have a distinctive format, spambots are easy to write.
A number of programs and approaches have been devised to foil spambots. One such technique is address munging
, in which an e-mail address is deliberately modified so that a human reader (and/or human-controlled Web browser
) can interpret it but spambots cannot. This has led to the evolution of more sophisticated spambots that are able to recover e-mail addresses from character strings that appear to be munged, or instead can render the text into a web browser and then scrape it for e-mail addresses. Alternative transparent techniques include displaying all or part of the e-mail address on a webpage as an image, a text logo shrunken to normal size using inline CSS
, or as text with the order of characters jumbled, placed into readable order at display time using CSS.
s, blog
s, forums
and other types of web forms
which it can then use to submit bogus content. These often use OCR
technology to bypass CAPTCHA
s. Some spam messages are targeted towards readers and can involve techniques of target market
ing or even phishing
, making it hard to tell real posts from the bot generated ones. Other spam message are not meant to be read by humans, but are instead posted to increase the number of hyperlink
s to a particular web site, to boost its search engine ranking.
This category of spambot has gained considerable notoriety since November 2006, with the introduction of XRumer
, a forum and wiki
spambot which can often bypass many of the safeguards administrators use to reduce the amount of spam posted.
One way to prevent spambots from creating automated posts is to require the poster to confirm their intention to post via e-mail. Since most spambot scripts use a fake e-mail address when posting, any email confirmation request is unlikely to be successfully routed to them. Some spambots will pass this step by providing a valid email address and use it for validation, mostly via webmail services. Using methods such as security questions are also proven to be effective in curbing posts generated by spambots, as they are usually unable to answer it upon registering.
from reaching the subscribers of an Internet service provider
(ISP). Such programs are more often called e-mail blockers or filters.
Blocking software may inadvertently prevent a legitimate e-mail message from reaching a subscriber. This can be prevented by allowing each subscriber to generate a whitelist, a list of specific e-mail addresses the blocker should let pass.
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
designed to assist in the sending of spam
Spam (electronic)
Spam is the use of electronic messaging systems to send unsolicited bulk messages indiscriminately...
. Spambots usually create fake accounts and send spam using them, although it would be obvious that a spambot is sending it. Some spambots, however, can crack passwords and send spam using other people's accounts.
E-mail spambots
E-mail spambots harvest e-mailE-mail
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...
addresses from material found on the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
in order to build mailing lists for sending unsolicited e-mail, also known as spam
E-mail spam
Email spam, also known as junk email or unsolicited bulk email , is a subset of spam that involves nearly identical messages sent to numerous recipients by email. Definitions of spam usually include the aspects that email is unsolicited and sent in bulk. One subset of UBE is UCE...
. Such spambots are web crawler
Web crawler
A Web crawler is a computer program that browses the World Wide Web in a methodical, automated manner or in an orderly fashion. Other terms for Web crawlers are ants, automatic indexers, bots, Web spiders, Web robots, or—especially in the FOAF community—Web scutters.This process is called Web...
s that can gather e-mail addresses from Web sites, newsgroups, special-interest group (SIG) postings, and chat-room conversations. Because e-mail addresses have a distinctive format, spambots are easy to write.
A number of programs and approaches have been devised to foil spambots. One such technique is address munging
Address munging
Address munging is the practice of disguising, or munging, an e-mail address to prevent it being automatically collected and used as a target for people and organizations who send unsolicited bulk e-mail...
, in which an e-mail address is deliberately modified so that a human reader (and/or human-controlled Web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...
) can interpret it but spambots cannot. This has led to the evolution of more sophisticated spambots that are able to recover e-mail addresses from character strings that appear to be munged, or instead can render the text into a web browser and then scrape it for e-mail addresses. Alternative transparent techniques include displaying all or part of the e-mail address on a webpage as an image, a text logo shrunken to normal size using inline CSS
CSS
-Computing:*Cascading Style Sheets, a language used to describe the style of document presentations in web development*Central Structure Store in the PHIGS 3D API*Closed source software, software that is not distributed with source code...
, or as text with the order of characters jumbled, placed into readable order at display time using CSS.
Forum spambots
Forum spambots surf the web, looking for guestbooks, wikiWiki
A wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. Wikis are typically powered by wiki software and are often used collaboratively by multiple users. Examples include...
s, blog
Blog
A blog is a type of website or part of a website supposed to be updated with new content from time to time. Blogs are usually maintained by an individual with regular entries of commentary, descriptions of events, or other material such as graphics or video. Entries are commonly displayed in...
s, forums
Internet forum
An Internet forum, or message board, is an online discussion site where people can hold conversations in the form of posted messages. They differ from chat rooms in that messages are at least temporarily archived...
and other types of web forms
Form (web)
A webform on a web page allows a user to enter data that is sent to a server for processing. Webforms resemble paper or database forms because internet users fill out the forms using checkboxes, radio buttons, or text fields...
which it can then use to submit bogus content. These often use OCR
Optical character recognition
Optical character recognition, usually abbreviated to OCR, is the mechanical or electronic translation of scanned images of handwritten, typewritten or printed text into machine-encoded text. It is widely used to convert books and documents into electronic files, to computerize a record-keeping...
technology to bypass CAPTCHA
CAPTCHA
A CAPTCHA is a type of challenge-response test used in computing as an attempt to ensure that the response is generated by a person. The process usually involves one computer asking a user to complete a simple test which the computer is able to generate and grade...
s. Some spam messages are targeted towards readers and can involve techniques of target market
Target market
A target market is a group of customers that the business has decided to aim its marketing efforts and ultimately its merchandise. A well-defined target market is the first element to a marketing strategy...
ing or even phishing
Phishing
Phishing is a way of attempting to acquire information such as usernames, passwords, and credit card details by masquerading as a trustworthy entity in an electronic communication. Communications purporting to be from popular social web sites, auction sites, online payment processors or IT...
, making it hard to tell real posts from the bot generated ones. Other spam message are not meant to be read by humans, but are instead posted to increase the number of hyperlink
Hyperlink
In computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...
s to a particular web site, to boost its search engine ranking.
This category of spambot has gained considerable notoriety since November 2006, with the introduction of XRumer
XRumer
XRumer is a Windows blackhat SEO program that is able to successfully register and forum spam with the aim of boosting search engine rankings. The program is able to bypass security techniques commonly used by many forums and blogs to deter automated spam, such as account registration, client...
, a forum and wiki
Wiki
A wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. Wikis are typically powered by wiki software and are often used collaboratively by multiple users. Examples include...
spambot which can often bypass many of the safeguards administrators use to reduce the amount of spam posted.
One way to prevent spambots from creating automated posts is to require the poster to confirm their intention to post via e-mail. Since most spambot scripts use a fake e-mail address when posting, any email confirmation request is unlikely to be successfully routed to them. Some spambots will pass this step by providing a valid email address and use it for validation, mostly via webmail services. Using methods such as security questions are also proven to be effective in curbing posts generated by spambots, as they are usually unable to answer it upon registering.
E-mail blockers
The term spambot sometimes has an inverse meaning, referring to a program designed to prevent spamE-mail spam
Email spam, also known as junk email or unsolicited bulk email , is a subset of spam that involves nearly identical messages sent to numerous recipients by email. Definitions of spam usually include the aspects that email is unsolicited and sent in bulk. One subset of UBE is UCE...
from reaching the subscribers of an Internet service provider
Internet service provider
An Internet service provider is a company that provides access to the Internet. Access ISPs directly connect customers to the Internet using copper wires, wireless or fiber-optic connections. Hosting ISPs lease server space for smaller businesses and host other people servers...
(ISP). Such programs are more often called e-mail blockers or filters.
Blocking software may inadvertently prevent a legitimate e-mail message from reaching a subscriber. This can be prevented by allowing each subscriber to generate a whitelist, a list of specific e-mail addresses the blocker should let pass.
See also
- BotnetBotnetA botnet is a collection of compromised computers connected to the Internet. Termed "bots," they are generally used for malicious purposes. When a computer becomes compromised, it becomes a part of a botnet...
- List poisoning
- SpamtrapSpamtrapA spamtrap is a honeypot used to collect spam.Spamtraps are usually e-mail addresses that are created not for communication, but rather to lure spam...
- Spider trapSpider TrapA spider trap is a set of web pages that may intentionally or unintentionally be used to cause a web crawler or search bot to make an infinite number of requests or cause a poorly constructed crawler to crash. Web crawlers are also called web spiders, from which the name is derived...
- Stopping e-mail abuseStopping e-mail abuseTo prevent e-mail spam , both end users and administrators of e-mail systems use various anti-spam techniques. Some of these techniques have been embedded in products, services and software to ease the burden on users and administrators...
External links
- Stas Bekman's Article on Botnets and how they are used for spamming
- Botnet discussion mailing list
- Harvester Killer – Fight back at spambots
- Fight Spam - Join Byteplant's Spambot Honeypot Project
- Spambot Beware! - information on how to avoid, detect, and harass spambots
- Bot-trap - A Bad Web-Robot Blocker
- How to block spambots