Difference between revisions of "Reducing spam in Moodle"

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Note: You are currently viewing documentation for Moodle 2.3. Up-to-date documentation for the latest stable version is available here: Reducing spam in Moodle.

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(Allowing self-registration: disabling self registration)
 
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Here are some suggestions for reducing the risk of spam in Moodle:
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{{Security}}
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==The best thing to do==
  
* Leave "Force users to login for profiles" enabled in ''Administration > Security > [[Site policies]]'' to keep anonymous visitors and search engines away from user profiles.
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Upgrade to the latest stable version of Moodle and use the [[Security_overview| Security report]] to analyse your configuration.  Then do all the things it tells you.
* Leave self registration disabled in ''Administration > Users > Authentication > [[Manage authentication]]'' common settings.
 
* Consider the [[Risks|spam risks]] involved in allowing certain capabilities, such as [[Capabilities/mod/forum:replypost| replying to forum posts]], for visitor accounts.
 
  
If [[Email-based self-registration]] is used for self registration:
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Note this is not strictly necessary to combat just profile spam (see the critical settings below) but it will protect you against dozens of other known security vulnerabilities.
* Add spam protection to the new account form by enabling reCAPTCHA (in Moodle 1.9.1 onwards). However, please realize that CAPTCHA will not foil manual attempts and there are CAPTCHA exploits now documented. In other words, CAPTCHA is NOT an ANSWER. It is only one more obstacle you might implement to discourage spammers.
 
* Limit self registration to particular email domains with the allowed email domains setting or deny email addresses from particular domains, such as mailinator.com and temporaryinbox.com, with the denied email domains setting. Both settings are in ''Administration > Users > Authentication > [[Manage authentication]]'' common settings.
 
* Consider only enabling self registration for a short period of time to allow users to create accounts, and then later disable it.
 
* Leave "Email change confirmation" enabled in ''Administration > Security > [[Site policies]]'' (in Moodle 1.8.6 or 1.9.2 onwards).
 
  
==Cleaning up profiles==
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==Critical settings==
If your site was open and you have a spam problem then here are some things you can do to clean up the profiles:
 
 
* Browse your user list looking for patterns to detect users who need to be deleted.  For example, spammers might have chosen a country that none of your real users has.
 
* Use the "Bulk user actions" tool under Admin > Users > Accounts to find all these users and delete them.  Note that versions prior to 1.6.7, 1.7.5, 1.8.6, 1.9.2 had a [http://moodle.org/mod/forum/discuss.php?d=101407 bug] that did not properly hide deleted user profiles, so make sure you have upgraded to a later version if you want to keep user profiles visible to the world.
 
* Some tools should shortly be available to make it easier to detect and delete profiles containing common spam content.  Check back here for details.
 
  
[[Category:Security]]
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# Make sure that 'register_globals' is switched '''off''' in your PHP settings (this is the default).  Otherwise your site may be at risk of being cracked, allowing spammers to modify your scripts and insert spam wherever they like.
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# Keep "Force users to login for profiles" '''enabled''' in ''Settings > Site administration > Security > [[Site policies]]'' to prevent anonymous visitors and search engines from seeing user profiles.
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# Keep "Profiles for enrolled users only" '''enabled''' in ''Settings > Site administration > Security > Site policies''.  This will prevent affected profiles from being visible even to other users on the site.
  
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==Strong recommendations==
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*Make sure you '''upgrade your site often'''.  Recent versions of Moodle have new fixes and warnings that will help you avoid security issues.
 +
*Consider the [[Risks|spam risks]] involved in allowing certain capabilities for visitor accounts, such as [[Capabilities/mod/forum:replypost| replying to forum posts]] or posting to blogs.
 +
 +
==Allowing self-registration==
 +
 +
If you don't need it, keep self-registration '''disabled''' (it's the default) in ''Settings > Site administration > Plugins > Authentication > Manage authentication'' common settings. 
 +
 +
If you '''must''' use [[Email-based self-registration]] to allow people to make their own accounts then:
 +
# Add spam protection to the new account form by enabling reCAPTCHA - see [[Security FAQ]] for details of how to do so. ReCAPTCHA is quite effective against '''most''' automated spambots, but will not foil human spammers at all.
 +
# Limit self registration to particular email domains with the allowed email domains setting or deny email addresses from particular domains, such as mailinator.com and temporaryinbox.com, with the denied email domains setting. Both settings are in ''Settings > Site administration > Users > Authentication > Manage authentication'' common settings.
 +
# Consider only enabling self registration for a short period of time to allow users to create accounts, and then later disable it by setting 'Self registration' to Disable in the common settings in ''Settings > Site administration > Plugins > Authentication > Manage authentication''.
 +
# Keep "Email change confirmation" enabled in ''Settings > Site administration > Security > [[Site policies]]''.
 +
 +
==Cleaning up spam==
 +
[[File:spam cleaner.png|thumb|Spam cleaner]]
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If your site was open in the past and you have a spam problem then here are some things you can do to clean up the profiles:
 +
 +
# Use our Spam cleaner report in ''Settings > Site administration > Reports > Spam cleaner'' to locate user accounts responsible for spam and other nasty stuff and help you delete them. In addition to user profile descriptions, comments, blog posts and messages are also searched for keywords.
 +
# Browse your user list looking for patterns to detect users who need to be deleted.  For example, spammers might have chosen a country that none of your real users has.
 +
# Use the delete buttons or the [[Bulk user actions]] tool in ''Settings > Site administration > Users > Accounts'' to find all these users and delete them.
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== See also ==
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* [[Security FAQ]]
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* [[Hacked site recovery]]
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[[Category:Report]]
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[[Category:Site administration]]
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[[es:Minimizar_el_spam_en_Moodle]]
 
[[eu:Spama_murriztu_Moodle-n]]
 
[[eu:Spama_murriztu_Moodle-n]]
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[[fr:Réduire le spam]]
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[[ja:Moodleでスパムを減らすには]]
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[[de:Spam reduzieren in Moodle]]

Latest revision as of 06:34, 13 February 2013

The best thing to do

Upgrade to the latest stable version of Moodle and use the Security report to analyse your configuration. Then do all the things it tells you.

Note this is not strictly necessary to combat just profile spam (see the critical settings below) but it will protect you against dozens of other known security vulnerabilities.

Critical settings

  1. Make sure that 'register_globals' is switched off in your PHP settings (this is the default). Otherwise your site may be at risk of being cracked, allowing spammers to modify your scripts and insert spam wherever they like.
  2. Keep "Force users to login for profiles" enabled in Settings > Site administration > Security > Site policies to prevent anonymous visitors and search engines from seeing user profiles.
  3. Keep "Profiles for enrolled users only" enabled in Settings > Site administration > Security > Site policies. This will prevent affected profiles from being visible even to other users on the site.

Strong recommendations

  • Make sure you upgrade your site often. Recent versions of Moodle have new fixes and warnings that will help you avoid security issues.
  • Consider the spam risks involved in allowing certain capabilities for visitor accounts, such as replying to forum posts or posting to blogs.

Allowing self-registration

If you don't need it, keep self-registration disabled (it's the default) in Settings > Site administration > Plugins > Authentication > Manage authentication common settings.

If you must use Email-based self-registration to allow people to make their own accounts then:

  1. Add spam protection to the new account form by enabling reCAPTCHA - see Security FAQ for details of how to do so. ReCAPTCHA is quite effective against most automated spambots, but will not foil human spammers at all.
  2. Limit self registration to particular email domains with the allowed email domains setting or deny email addresses from particular domains, such as mailinator.com and temporaryinbox.com, with the denied email domains setting. Both settings are in Settings > Site administration > Users > Authentication > Manage authentication common settings.
  3. Consider only enabling self registration for a short period of time to allow users to create accounts, and then later disable it by setting 'Self registration' to Disable in the common settings in Settings > Site administration > Plugins > Authentication > Manage authentication.
  4. Keep "Email change confirmation" enabled in Settings > Site administration > Security > Site policies.

Cleaning up spam

Spam cleaner

If your site was open in the past and you have a spam problem then here are some things you can do to clean up the profiles:

  1. Use our Spam cleaner report in Settings > Site administration > Reports > Spam cleaner to locate user accounts responsible for spam and other nasty stuff and help you delete them. In addition to user profile descriptions, comments, blog posts and messages are also searched for keywords.
  2. Browse your user list looking for patterns to detect users who need to be deleted. For example, spammers might have chosen a country that none of your real users has.
  3. Use the delete buttons or the Bulk user actions tool in Settings > Site administration > Users > Accounts to find all these users and delete them.

See also