Spam: Difference between revisions

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* [http://en.wikipedia.org/wiki/Captcha http://en.wikipedia.org/wiki/Captcha]
* [http://en.wikipedia.org/wiki/Captcha http://en.wikipedia.org/wiki/Captcha]


; Making user creation more difficult with recaptcha and contributes to a digitalization project.
; Making user creation even more difficult with recaptcha
: Also contributes to a digitalization project....
* [http://recaptcha.net/plugins/mediawiki/ Mediawiki extension] (repcaptcha)
* [http://recaptcha.net/plugins/mediawiki/ Mediawiki extension] (repcaptcha)
* [http://recaptcha.net/learnmore.html Learn more about the project]
* [http://recaptcha.net/learnmore.html Learn more about the project]

Revision as of 13:35, 16 July 2010

Draft

Lookup IP addresses and domain names

This may allow to block whole domains (e.g. in the httpd.conf file or at the system level). When you use a difficult user account procedure as in this wiki, then wikis can spammed manually (typically by third-world people underpaid by a first-world company) and this can help a bit.

If your Mediawiki is spammed: first you will have to go either through your web server logs, e.g. search for "submitlogin" or install an extension that shows the IP number of users.

The CheckUser extension
allows you to figure out where they come from (connect from) and may help you decide whether you should block a whole IP range or ranges (e.g. a whole country). You either can enter user names or IP numbers. Then you can both trace and block a user.
Installed on EduTechwiki and also some Wikipedia/media sites.

Alternatively dig through web server access logs and then consult one of these:

Mediawiki spamming

There exist several strategies:

Registered users

To fight spamming, only registered uses should be able to edit. Edit Localsettings.php

$wgGroupPermissions['*']['edit']            = false;
$wgGroupPermissions['*']['createaccount']   = true;
$wgGroupPermissions['*']['read']            = true;
Light-weight user creation that requires some math

This can defeat some scripts

Making user creation more difficult with captcha

This can defeat more scripts

Making user creation even more difficult with recaptcha
Also contributes to a digitalization project....

This extension is currently used in Edutechwiki with (roughly the following setup)

# Anti Spam ConfirmEdit
# Recaptcha relies on ConfirmEdit, but only ONE needs to be loaded
# require_once("extensions/ConfirmEdit/ConfirmEdit.php");

# ReCaptcha
# See the docs in extensions/recaptcha/ConfirmEdit.php
# http://wiki.recaptcha.net/index.php/Main_Page
require_once( "$IP/extensions/recaptcha/ReCaptcha.php" );
$recaptcha_public_key = '................';
$recaptcha_private_key = '................';

# Users must be registered, once they are in, they they still must fill in captchas (at least over the summer)
$wgCaptchaTriggers['edit']          = true;
$wgCaptchaTriggers['addurl']        = false;
$wgCaptchaTriggers['create']        = true;
$wgCaptchaTriggers['createaccount'] = true;

Filtering edits and page names

Prevent creation of pages with bad words in the title and/or the text.

The builtin WgSpamRegex variable

Mediawiki includes a $wgSpamRegex variable. The goals is prevent three things: (a) bad words, (b) links to bad web sites and (c) CSS tricks to hide contents.

Insert in LocalSettings.php something like:

$wgSpamRegex = "/badword1|barword2|abcdefghi-website\.com|display_remove_:none|overflow_remove_:\s*auto;\s*height:\s*[0-4]px;/i"

I will not show ours here since I can't include it in this page ;)

Read the manual page for detail. It includes a longer regular expression that you may adopt.

Don't forget to edit MediaWiki:Spamprotectiontext

Spam blacklists extensions (an alternative)

The SpamBlacklist extension prevents edits that contain URL hosts that match regular expression patterns defined in specified files or wiki pages.

rel = "nofollow"

Wiki spammers aim at two things:

  • Insert well placed links in articles dealing somewhat with the spam content's subject area so that people will actually see them and then follow (same principle as google ads). This requires understanding of an article content. Since most wiki spammers are poorly trained and paid people from poor non-English speaking countries, this strategy most often fails.
  • Get a better Google ranking. This second purpose will not work in this wiki, since “{{{1}}}” (Manual:Combating spam. Most wiki spammers abusing edutechwiki are too stupid to know about this (some labour really must come cheap ....)

To some companies wiki spamming may seem to be a good strategy, but most often it is not...

Links

General

Legal issues and official policy

Note:

  • Wiki spamming is worse than e-mail spamming, because it relates to vandalism and therefore additional laws can apply.
  • Official EU and OECD websites are often unstable (link decay, e.g. the www.oecd-antispam.org official website which is linked to from many places is dead ...)
USA (main direct or indirect source of spamming)
EU
UK

General wiki spamming

Examples from content guidelines - what is spam ?

Mediawiki

  • Spam Filter (This is development page of Mediawiki. I includes extra information, e.g. cleanup scripts.)
  • Help:Spam (Wikia) Wikia is a commercial version of Wikipedia with many user-managed subwikis that have their own aims and content policies.

Bibliography

  • West, Andrew G., Sampath Kannany and Insup Lee (2010). Detecting Wikipedia Vandalism via Spatio-Temporal Analysis of Revision Metadata, Department of Computer & Information Science, Technical Reports (CIS), University of Pennsylvania. PDF. See also: STiki (Spatio-Temporal analysis over Wikipedia)
  • M. Potthast, B. Stein, and R. Gerling (2008). Automatic vandalism detection in Wikipedia. In Advances in Information Retrieval, pages 663-668