MediaWiki

Extension:ConfirmEdit

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This extension comes with MediaWiki 1.18 and above. Thus you do not have to download it again. However, you still need to follow the other instructions provided.
MediaWiki extensions manual
ConfirmEdit
Release status: stable
Implementation Page action
Description Adds CAPTCHAs for page saves and other user actions
Author(s)
  • Brooke Vibber
  • Florian Schmidt
  • Sam Reed
Latest version 1.6.0 (Continuous updates)
Compatibility policy Snapshots releases along with MediaWiki. Master is not backward compatible.
MediaWiki >= 1.43
License GNU General Public License 2.0 or later
Download
Download extension
Git [?]:
Parameters
  • $wgAllowConfirmedEmail
  • $wgCaptchaBadLoginExpiration
  • $wgCaptchaTriggersOnNamespace
  • $wgCaptchaStorageClass
  • $wgConfirmEditEnabledAbuseFilterCustomActions
  • $wgCaptchaSessionExpiration
  • $wgCaptchaRegexes
  • $wgCaptchaWhitelistIP
  • $wgCaptchaWhitelist
  • $wgCaptchaTriggers
  • $wgCaptchaBadLoginPerUserAttempts
  • $wgCaptchaBadLoginPerUserExpiration
  • $wgCaptcha
  • $wgCaptchaBadLoginAttempts
Added rights
  • skipcaptcha
Hooks used
Quarterly downloads 152 (Ranked 37th)
Public wikis using 957 (Ranked 278th)
Translate the ConfirmEdit extension if it is available at translatewiki.net
Vagrant role confirmedit
Issues Open tasks · Report a bug

The ConfirmEdit extension lets you use various CAPTCHA techniques to try to prevent spambots and other automated tools from editing your wiki, as well as to foil automated login attempts that try to guess passwords.

ConfirmEdit ships with several techniques/modules to generate a captcha.

Module Description Effectiveness at stopping spam
SimpleCaptcha Users have to solve a simple math problem. Low
FancyCaptcha Users have to identify a series of characters displayed in a stylized way. Low
MathCaptcha Users have to solve a math problem that's displayed as an image. Low
QuestyCaptcha Users have to answer a question out of a series of questions defined by the administrator(s). Very high, until cracked
ReCaptcha NoCaptcha Users are presented with a JavaScript-based check of humanity. If the check is failed, a puzzle is presented. Medium to low
hCaptcha Similar to reCAPTCHA, but is arguably more effective than reCAPTCHA because of its different approach to accessibility-friendly captchas. Unknown
Turnstile Cloudflare Turnstile. Human actionless (or click the box) bot detector. Unknown

Some of these modules require additional setup work:

  • MathCaptcha requires both the presence of TeX and, for versions of MediaWiki after 1.17, the Math extension;
  • FancyCaptcha requires running a preliminary setup script in Python.

Drawbacks

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CAPTCHAs reduce accessibility and cause inconvenience to human users.

They also are not 100% effective against bots, and they will not protect your wiki from spammers who are willing and able to use human labor to get through the CAPTCHAs. You may wish to use ConfirmEdit in conjunction with other anti-spam features. Regardless of the solution you use, if you have a publicly-editable wiki, it's important to keep monitoring the "Recent changes" page.

Installation

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ConfirmEdit may not work if used with a MediaWiki version different from the one specified when downloading via the "Extension distributor".
  • Download and move the extracted ConfirmEdit folder to your extensions/ directory.
    Developers and code contributors should install the extension from Git instead, using:cd extensions/
    git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/ConfirmEdit
  • Add the following code at the bottom of your LocalSettings.php file: 
    wfLoadExtension( 'ConfirmEdit' );
  • Enable the CAPTCHA type which should be used
  • Configure as needed
  •   Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.


Vagrant installation:

  • If using Vagrant , install with vagrant roles enable confirmedit --provision

CAPTCHA types

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There are numerous different CAPTCHA types included with ConfirmEdit.

QuestyCaptcha

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This module presents a question, and the user supplies the answer. You provide the questions in the configuration. This module has proven to offer a strong mechanism against spambots; it should also have the advantage of better accessibility, as textual questions can be read by text-to-speech software allowing visually impaired users (but not bots) to answer correctly.

Add the following to LocalSettings.php to enable this CAPTCHA, editing the Q&A: 

wfLoadExtensions([ 'ConfirmEdit', 'ConfirmEdit/QuestyCaptcha' ]);

// Add your questions in LocalSettings.php using this format:
$wgCaptchaQuestions = [
	'What is the capital of France?' => 'Paris',
	'What is the capital of Spain' => 'MADRID', // Answers are case insensitive
	'What is the name of this wiki?' => $wgSitename, // You can use variables
	'How many fingers does a hand have?' => [ 5, 'five' ], // A question may have many answers
];

It will randomly choose a question from those supplied.

The minimum is one.

  • QuestyCaptcha is case-insensitive. If the answer is "Paris" and the user writes "paris", or if the answer is "paris" and the user writes "Paris", it will still work.
  • If the answer has a special character like "ó", you may write an answer with "ó" and another with "o" (where "o" replaces "ó"), just in case. For example, if the answer is "canción" you can use [ 'cancion', 'canción' ] in case the user writes "cancion".
  • The answer must be easy to guess for a human interested in your wiki, but not by an automatic program. Ideally, it should not be contained in the text of the question; you can try and edit the captcha help messages and provide the solution to the captcha response there.[1]
  • Change the questions when/if they start proving ineffective; this may never happen if your wiki is not specifically targeted.
  • Don't ever reuse questions already used by you or others in the past: spambots are known to remember a question and its answer forever once they break it.
  • You can even dynamically generate questy captchas in the configuration. DO NOT use an exact copy of the dynamic questions from the link. Spammers have cracked them. However, other dynamic questions are highly effective in the style of the questions presented.
  • There is a separate extension to ConfirmEdit called QuestyCaptchaEditor which provides an on-wiki special page for managing QuestyCaptcha question+answer(s) pairings. You may wish to consider installing it if it's desirable to reduce sysadmin intervention when it comes to managing the CAPTCHA questions and their answers.

ReCaptcha (NoCaptcha)

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  Warning: ReCaptcha has been cracked by most spambots targeting wikis, mainly due to its accessible captcha alternative.

The new generation of ReCaptcha, called NoCaptcha, was introduced by Google back in December 2014 and reduces the need for humans to solve a CAPTCHA.[2] Based on a user-side JavaScript (which can't be controlled by the user, the administrator), reCaptcha tries to identify the site user as a human by analyzing their browsing behavior on the page. The user then has to click an "I'm not a robot" checkbox and (in the best case) doesn't have to do anything further to prove they're a human. In some cases, the user still has to solve a CAPTCHA image.

ReCaptcha will not work with the Mobile Source Editor and some extensions.

This module implements the new ReCaptcha NoCaptcha solution in ConfirmEdit.

You still need a public and a secret key (which you can retrieve from the ReCaptcha admin panel – change v2, v3 not work) and install the plugin with: 

wfLoadExtensions([ 'ConfirmEdit', 'ConfirmEdit/ReCaptchaNoCaptcha' ]);
$wgReCaptchaSiteKey = 'your public/site key here';
$wgReCaptchaSecretKey = 'your private key here';

There is an additional configuration option for this module, $wgReCaptchaSendRemoteIP (default: false), which, if set to true, sends the IP address of the current user to a server from Google while verifying the CAPTCHA. You can improve the privacy for your users if you keep this set to false. However, remember that this module adds a client-side JavaScript code, directly loaded from a server from Google, which already can collect the IP address of the user (combined with other data, too) and can not be limited by a configuration option. This will only work on the standard MediaWiki editor.

reCAPTCHA v3

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Currently, there is no official way to implement version 3 of Google reCAPTCHA.

SimpleCaptcha (calculation)

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  Warning: This type is used by very few wikis, if any, probably because of scarce effectiveness.
 
A simple math question

This is the default CAPTCHA.

This module provides a simple addition or subtraction question for the user.

Add the following lines to LocalSettings.php in the root of your MediaWiki to enable this CAPTCHA: 

$wgCaptchaClass = 'SimpleCaptcha';

Note that the display of a trivial maths problem as plaintext yields a captcha which can be trivially solved by automated means; as of 2012, sites using SimpleCaptcha are receiving significant amounts of spam and many automated registrations of spurious new accounts. Wikis currently using this as the default should therefore migrate to one of the other CAPTCHAs.

FancyCaptcha

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  Warning: This type is used by very few wikis outside WMF, if any, probably because of scarce effectiveness.
 

This module displays a stylized image of a set of characters.

Pillow must be installed to create the set of images initially, but isn't needed after that (can be installed with pip install Pillow in most environments).

  1. Add the following lines to LocalSettings.php in the root of your MediaWiki installation:
    wfLoadExtensions([ 'ConfirmEdit', 'ConfirmEdit/FancyCaptcha' ]);
    $wgCaptchaClass = 'FancyCaptcha';
  2. In LocalSettings.php, set the variable $wgCaptchaDirectory to the directory where you will store Captcha images. Note: use the absolute directory path or relative to your wiki's installation directory Below it set $wgCaptchaSecret to your passphrase.
  3. Create the images by running the following:
    python /path/to/captcha.py --font=<font> --wordlist=<wordlist> --key=<key> --output=<output> --count=<count>
    • where font is a path to some font, for instance AriBlk.TTF.
    • wordlist is a path to some word list, for instance /usr/share/dict/words. (Note: on Debian/Ubuntu, the 'wbritish' and 'wamerican' packages provide such lists. On Fedora, use the 'words' package)
    • key is the exact passphrase you set $wgCaptchaSecret to. Use quotes if necessary.
    • output is the path to where the images should be stored (defined in $wgCaptchaDirectory).
    • count is how many images to generate.
    • An example, assuming you're in the extensions/ConfirmEdit directory (font location from Ubuntu 6.06, probably different on other operating systems):
    python captcha.py --font=/usr/share/fonts/truetype/freefont/FreeSans.ttf --wordlist=/usr/share/dict/words --key=FOO --output=../../../captcha --count=100
    • If you are not satisfied with the results of the words you've generated, you can remove the images and create a new set. Comic_Sans_MS_Bold.ttf seems to generate relatively legible words, and you could also edit the last line of captcha.py to increase the font size from the default of 40.
  4. Put the images you get into captcha directory in your installation.
  5. Edit your wiki's LocalSettings.php : specify the full path to your captcha directory in $wgCaptchaDirectory and secret key you've been using while generating captures in $wgCaptchaSecret.
$wgCaptchaDirectory = "/.php-data/my-wiki.org/wiki/captcha";
$wgCaptchaDirectoryLevels = 0; // Set this to a value greater than zero to break the images into subdirectories
$wgCaptchaSecret = "FOO"; // Same value you used in --key option in captcha.py

See also wikitech:Generating CAPTCHAs for how the Wikimedia Foundation does it.

How to avoid common problems running Python on Windows
  1. Install the most recent version of Pillow.
  2. Make the installation of Python on a short folder name, like C:\Python\
  3. Create a folder like C:\Ex and place files CAPTCHA.py / FONT.ttf / LIST.txt into the folder.
  4. To execute easily, run the following example as a batch file:
C:\python\python.exe C:\Ex\CAPTCHA.py --font C:\Ex\FONT.ttf --wordlist C:\Ex\LIST.txt --key=YOURPASSWORD --output C:\Ex\ --count=20

MathCaptcha

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MediaWiki version:
≤ 1.39
  Warning: This type is used by very few wikis, if any, probably because of scarce effectiveness.
This requires the Math extension to be installed. Also, since this requires the PNG mode of the Math extension, it no longer works since MediaWiki 1.40.

This module generates an image using TeX to ask a basic math question.

Set the following to enable this CAPTCHA: 

wfLoadExtensions([ 'ConfirmEdit', 'ConfirmEdit/MathCaptcha' ]);

See the README file in the math folder to install this captcha.

hCaptcha

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MediaWiki version:
≥ 1.35

See https://www.hcaptcha.com/

The configuration is similar to ReCaptcha: 

wfLoadExtensions([ 'ConfirmEdit', 'ConfirmEdit/hCaptcha' ]);
$wgHCaptchaSiteKey = 'your public/site key here';
$wgHCaptchaSecretKey = 'your private key here';

$wgHCaptchaSendRemoteIP is also available.

Turnstile

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MediaWiki version:
≥ 1.42

The configuration is similar to #ReCaptcha or #hCaptcha: 

wfLoadExtensions([ 'ConfirmEdit', 'ConfirmEdit/Turnstile' ]);
$wgTurnstileSiteKey= 'your public/site key here';
$wgTurnstileSecretKey= 'your private key here';

$wgTurnstileSendRemoteIP is also available.

Configuration

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Don't require CAPTCHA from some users

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ConfirmEdit introduces a 'skipcaptcha' permission type to wgGroupPermissions . This lets you set certain groups never to see CAPTCHAs. All of the following can be added to LocalSettings.php.

Defaults from ConfirmEdit.php: 

$wgGroupPermissions['*']['skipcaptcha'] = false;
$wgGroupPermissions['user']['skipcaptcha'] = false;
$wgGroupPermissions['autoconfirmed']['skipcaptcha'] = false;
$wgGroupPermissions['bot']['skipcaptcha'] = true; // registered bots
$wgGroupPermissions['sysop']['skipcaptcha'] = true;

To skip captchas for users who confirmed their email, you need to set both: 

$wgGroupPermissions['emailconfirmed']['skipcaptcha'] = true;
$wgAllowConfirmedEmail = true;

Set actions that require CAPTCHA

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The following conditions can trigger a CAPTCHA to be displayed:

  • 'edit' - triggered on every attempted page save
  • 'create' - triggered on page creation
  • 'sendemail' - triggered when using Special:Emailuser
  • 'addurl' - triggered on a page save that would add one or more URLs to the page
  • 'createaccount' - triggered on creation of a new account
  • 'badlogin' - triggered after several failed login attempts from the same IP address
  • 'badloginperuser' - triggered after several failed login attempts using the same username

The default values for these are: 

$wgCaptchaTriggers['edit'] = false;
$wgCaptchaTriggers['create'] = false;
$wgCaptchaTriggers['sendemail'] = false;
$wgCaptchaTriggers['addurl'] = true;
$wgCaptchaTriggers['createaccount'] = true;
$wgCaptchaTriggers['badlogin'] = true;
$wgCaptchaTriggers['badloginperuser'] = true;

The triggers edit, create and addurl can be configured per namespace using the $wgCaptchaTriggersOnNamespace setting. If there is no $wgCaptchaTriggersOnNamespace for the current namespace, the normal $wgCaptchaTriggers apply. So suppose that in addition to the above $wgCaptchaTriggers defaults we configure the following: 

$wgCaptchaTriggersOnNamespace[NS_TALK]['addurl'] = false;
$wgCaptchaTriggersOnNamespace[NS_PROJECT]['edit'] = true;

Then the CAPTCHA will not trigger when adding URLs to a talk page, but on the other hand user will need to solve a CAPTCHA any time they try to edit a page in the project namespace, even if they aren't adding a link.

URL and IP whitelists

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It is possible to define a whitelist of known good sites for which the CAPTCHA should not kick in when the 'addurl' action is triggered.

Sysop users can edit the system message page called MediaWiki:Captcha-addurl-whitelist.

The expected format is a set of regex's one per line.

Comments can be added with # prefix.

You can see an example of this usage on OpenStreetMap.

This set of whitelist regexes can also be defined using the $wgCaptchaWhitelist config variable in LocalSettings.php, to keep the value(s) a secret.

Some other variables you can add to LocalSettings.php:

  • $wgCaptchaWhitelistIP - List of IP ranges to allow to skip the CAPTCHA (you can also use MediaWiki:Captcha-ip-whitelist; see below for details).
  • $wgAllowConfirmedEmail - Allow users who have confirmed their e-mail addresses to post URL links.

These are described more thoroughly in the code comments

MediaWiki:Captcha-ip-whitelist can change the whitelisted IP addresses and IP ranges on the wiki.

They should be separated by newlines.

If any other character (apart from a valid IP address or range) is found on a line, it will be ignored, but leading and trailing whitespace characters are allowed.

For example, a line with only 127.0.0.1 is considered valid but #127.0.0.1 will be ignored.

Regular expressions

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The global variable wgCaptchaRegexes accepts an array of regexes to be tested against the page text and triggers the CAPTCHA if a match is found.

Failed login attempts

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When using the badlogin or badloginperuser triggers, the following configuration variables control how many failed login attempts per-IP and per-user are allowed before a CAPTCHA is required, and how long it takes until the CAPTCHA requirement expires: 

$wgCaptchaBadLoginAttempts = 3;
$wgCaptchaBadLoginExpiration = 300; // 300 seconds = 5 minutes
$wgCaptchaBadLoginPerUserAttempts = 20;
$wgCaptchaBadLoginPerUserExpiration = 600; // 600 seconds = 10 minutes

The triggers require $wgMainCacheType to be set to something other than CACHE_NONE in your LocalSettings.php, if in doubt the following will always work. 

$wgMainCacheType = CACHE_ANYTHING;

Note that these triggers do not trigger CAPTCHAs on API login but block them outright until the CAPTCHA requirement expires.

Wikimedia configuration

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For example, Wikimedia Foundation wikis use FancyCaptcha with a custom set of images and the default configuration, modified by what follows. 

$wgGroupPermissions['autoconfirmed']['skipcaptcha'] = true;

This means only unregistered and newly registered users have to pass the CAPTCHA.

EmergencyCaptcha mode

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Additionally, the shortcut named $wmgEmergencyCaptcha is designed for use in a limited number of emergencies, for instance, in case of massive vandalism or spam attacks: it changes the default trigger values (see above) into the following: 

$wgCaptchaTriggers['edit'] = true; 
$wgCaptchaTriggers['create'] = true;

So, in addition to the normal situation, all anonymous and new users have to solve a CAPTCHA before being able to save an edit or create a new page.

Rate-limiting

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ConfirmEdit supports rate limiting for false CAPTCHA.

For more information about $wgRateLimits and how to set it up, read Manual:$wgRateLimits , the action key is badcaptcha.

Authors

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The basic framework was primarily designed by Brion Vibber, who also wrote the SimpleCaptcha and FancyCaptcha modules.

The MathCaptcha module was written by Rob Church.

The QuestyCaptcha module was written by Benjamin Lees.

Additional maintenance work was done by Yaron Koren.

References

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  1. ↑ MediaWiki:Questycaptchahelp-text, MediaWiki:Questycaptcha-edit, MediaWiki:Questycaptcha-addurl, MediaWiki:Questycaptcha-create, MediaWiki:Questycaptcha-createaccount
  2. ↑ Google Blog Are you a robot? Introducing “No CAPTCHA reCAPTCHA” ()

See also

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