Black List Plugin

Description

This is a simple utility to keep black sheep away from a public Foswiki site. The site can be protected against excessive page access (e.g. by bad robots), suspicious activities of users, such as multiple registrations or rapid topic updates indicating Wiki:WikiSpam, or saving text with wiki-spam.

The Plugin monitors activities by IP address and uses three IP address lists to protect the Foswiki site:

• WHITELIST: Manually maintained list of users who should never get on the BANLIST
• BLACKLIST: Manually maintained list of malicious users
• BANLIST: Automatically updated list of users with suspicious activities

On topic save, text is compared to a known list of spam patterns. If wiki-spam is identified, topic save is cancelled, an error message is shown, and the IP address is put on the BANLIST. Two wiki-spam lists are used:

• Local SPAMLIST: Manually maintained list of spam patterns
• Public wiki-spam list: Big list of wiki-spam patterns, retrieved from external web site

Users on the BLACKLIST and BANLIST will have every page access delayed by at least 5 seconds and will get an error message.

The ban can be set to expire after a number of minutes to minimize maintenance where spammers use dynamic IP addresses or someone accidently gets banned.

To fight wiki-spam, the plugin can also add a rel="nofollow" parameter to external URLs. Search engines will not follow links that have this parameter, taking away the incentive to add spam to Foswiki.

Plugin Settings

Plugin settings are stored as preferences variables. To reference a plugin setting write %<plugin>_<setting>%, i.e. %BLACKLISTPLUGIN_SETTING%

Note: Settings made in this plugin topic will be overwritten next time you upgrade the plugin. You are advised to define the settings in SitePreferences using the format %BLACKLISTPLUGIN_SETTING%. Remember to add the settings to the list of FINALPREFERENCES in SitePreferences.

General settings

• One line description, is shown in the TextFormattingRules topic:
  • Set SHORTDESCRIPTION = Utility to keep malicious users away from a public Foswiki site

• Debug plugin: (See output in data/debug.txt)
  • Set DEBUG = 0

• Log access of blacklist and spam list activities: (0 or 1)
  • Set LOGACCESS = 1

• Access restriction:
  • Set ALLOWTOPICCHANGE = AdminGroup
  • Set ALLOWTOPICRENAME = AdminGroup

WHITELIST, BLACKLIST and BANLIST settings

• WHITELIST: Comma delimited list of IP addresses; possible to use partial addresses ending in a dot
  • Set WHITELIST = 127.0.0.1

• BLACKLIST: Comma delimited list of IP addresses; possible to use partial addresses ending in a dot
  • Set BLACKLIST =

• BANLIST: Automatically updated list of IP addresses based on BANLIST configuration
  • Action: Add Remove IP address(es)
  • Current list (expires in mins):

• BANLIST configuration, comma delimited list of:
  1. Points for registration
  2. Points for each save and upload
  3. Points for view and other actions
  4. Points for view raw
  5. Threshold to add to BANLIST
  6. Measured over time (in seconds)
  • Set BANLISTCONFIG = 10, 5, 1, 5, 120, 300
  • Your current score: 1 for IP address 10.10.20.20

• Message for users on BLACKLIST and BANLIST:
  • Set BLACKLISTMESSAGE = Your IP address 10.10.20.20 is black listed at the Foswiki web site due to excessive access or suspicious activities. Please contact site administrator postmaster@digitalmethodsREMOVE_ME.net if you got on the list by mistake.

• Set the time in minutes until the ban for an IP address expires. Set it to 0 for infinite ban. It is a good idea to define a time since most IP addresses used by spammers are dynamic anyway. It also saves you manual process of users that accidently got banned because they know they can just wait an hour or so. Values like 60 (one hour) or 720 (one day) are good values. Default if the setting is not defined is 0 (disabled).
  • Set BANEXPIRE = 60

Wiki-spam filtering settings

• Filter wiki-spam on topic save and HTML file uploads based on SPAMLIST: (0 or 1)
  • Set FILTERWIKISPAM = 1

• Comma separated list of Web.Topics to exclude from wiki-spam filtering on topic save:
  • Set SPAMEXCLUDETOPICS = PapersPublications

• Local SPAMLIST: Manually maintained list of spam patterns (NOTE: Must be RegularExpression patterns)
  • Action: Add Remove wiki-spam regex pattern(s) http://.*?
  • Current list:

• EXCLUDELIST: Manually maintained list of exceptions to public wiki-spam patterns, useful to exclude patterns listed incorrectly as spam
  • NOTE: These are RegularExpression patterns which are applied to the public wiki-spam pattern list. The final regular expression that is used to detect wiki-spam is built roughly as follows:
    • The public wiki-spam list is downloaded
    • Joined with local SPAMLIST
    • Comment lines are removed
    • Lines containing spaces or '<' or '>' characters are removed
    • Each EXCLUDELIST pattern is applied to the (newline separated) expression that's been built so far
    • Matching regions of the expression are deleted
    • Empty lines are removed
    • Remaining newlines are removed and joined with '|'
  • Action: Add Remove exclude spam regex pattern(s) http://.*?
  • Current list:

• Public wiki-spam list: a big list of wiki-spam patterns, retrieved from external web site (thanks to MoinMoin's AntiSpamGlobalSolution wiki-spam list)
  • Set SPAMLISTURL = http://arch.thinkmo.de/cgi-bin/spam-merge

• Cache refresh time (in minutes) for public wiki-merge pattern list:
  • Set SPAMLISTREFRESH = 60

• Cache refresh time (in minutes) for internal wiki-spam regular expression cache:
  • Set SPAMREGEXREFRESH = 10

• Message for users trying to save text with wiki-spam:
  • Set WIKISPAMMESSAGE = Wiki-spam detected: "%WIKISPAMWORD%" is a banned word and cannot be saved. Your IP address 10.10.20.20 is banned at the Foswiki web site due to suspicious activities. Please contact site administrator postmaster@digitalmethodsREMOVE_ME.net if you got on the list by mistake. The ban will expire after a time set by the administrator.

Nofollow link setting

• Add a rel="nofollow" parameter to external URLs. Use this is to fight Wiki-spam. Search engines will not follow the link if a URL has a nofollow parameter, such as <a href="http://spammer.com/" rel="nofollow">. Specify topic age in hours for which the nofollow parameter should appear (set it to a value that gives you enough time to remove spam); set it to -1 to add the nofollow parameter unconditionally to external URLs; or 0 to disable: (-1, 0, 1...N)
  • Set NOFOLLOWAGE = -1

Plugin Installation Instructions

Note: You do not need to install anything on the browser to use this plugin. The following instructions are for the administrator who installs the plugin on the server where Foswiki is running.

• Download the ZIP file from the Plugin web (see below)
• Unzip BlackListPlugin.zip in your Foswiki installation directory. Content:

  File:	Description:
  data/System/BlackListPlugin.txt	Plugin topic
  lib/Foswiki/Plugins/BlackListPlugin.pm	Plugin Perl module

• Run the configure utility in your browser to enable the Plugin
• Make sure that non-administrators cannot edit this plugin topic. By default, this topic is write protected with an ALLOWTOPICCHANGE = AdminGroup setting.
• Test if the installation was successful:
  1. Using above form, add the IP address of one of your workstations to the BANLIST
  2. Access Foswiki from that workstation
     • if you look at a Foswiki topic (with the view script) you should see the BLACKLISTMESSAGE (defined above) after a small timeout
     • else, you should get an 500 Internal Server Error for other scripts
  3. On a different workstation, remove the IP address of the test workstation from the BANLIST

Known Issues and Limitations

• Scan for script eval() and escape() is currently hardcoded

Plugin Info

Plugin Author:	Foswiki:Main.KennethLavrsen (from 2009), TWiki:Main/PeterThoeny (until 2007)
Plugin Version:	08 Jan 2010
Change History:
08 Jan 2010:	Foswikitask:Item2576 Minor documentation changes Foswikitask:Item2577 Also support https spam links
04 Jan 2010:	Several bug fixes and enhancements Besides the tasks listed below much of the code has been re-written Foswikitask:Item2500 Magic key protection of registration removed as this has become core feature in Foswiki 1.0.9 Foswikitask:Item1740 Fixed problem with whitelist not preventing being blacklisted Foswikitask:Item5409 Fixed problem oopblacklist not showing anything. Now using generic message template instead of an oopsblacklist template Foswikitask:Item5697 Fixed problem when not setting any banned regexp causes all external links to be detected as spam Foswikitask:Item1257 Fixed problem where plugin dies on save if not connected to the internet Foswikitask:Item2570 Plugin no longer needs anything in pub. Removed the entire pub directory from distribution. Upgraders can delete it. Foswikitask:Item2571 Plugin now has a new feature so banned IP addresses can automatically expire Foswikitask:Item2572 Plugin now waits only 5 seconds with banned IP to avoid itself a DOS target. Message reduced to simple text screen that does not load Foswiki as much during a site sucking attack Foswikitask:Item2573 Plugin no longer ships with default blacklisted IP ranges. The admins should decide themselves at installation
20 Mar 2009:	Ported to Foswiki by Kenneth Lavrsen and given as Feel Free To Modify in Foswiki context
29 Mar 2007:	Doc fixes; change view=raw penalty from 20 to 5
18 Mar 2007:	Scan for evil script eval() and escape() in topic text and attachments; support for TWiki 4.2 (using new TWiki::Func::getExternalResource)
28 Dec 2006:	Fixed bug where EXCLUDELIST pattern was removing only part of a wiki-spam pattern
27 Dec 2006:	Support for TWiki 4.1
01 Jul 2006:	Added EXCLUDELIST; scan for evil script eval in attachments; scan also .js and .css attachments; fixed writeLog error on Cairo
02 Jun 2006:	Added wiki-spam filtering for HTML attachments to combat TWiki:Codev.HtmlAttachmentSpam
29 Apr 2006:	Added %BLACKLISTPLUGIN{ action="spam_show_n" }% that shows the local spam list in a shareable format with newline separator
07 Feb 2006:	TWiki Release 4.0 fix to allow registration with e-mail verification, reset password and approve
03 Jan 2006:	Filter lines with space from spam list; fixed bug that inproperly filtered HTML from spam list; Dakar Release fix (end/postRenderingHandler issue)
08 Nov 2005:	Doc fixes; code warning fixes; allow empty local SPAMLIST and public spam list
04 Nov 2005:	Added registration protection with magic number
30 Oct 2005:	Dakar Release compatibility: Work around Dakar preferencs bug
29 Oct 2005:	Added wiki-spam filtering to prevent topic save with wiki-spam
27 Oct 2005:	For BANLIST, add/remove multiple IP addresses at once, contributed by Foswiki:Main.MichaelDaum
22 Jan 2005:	Added NOFOLLOWAGE handling
19 Jan 2005:	Added score for "view raw" to address e-mail harvester issue
05 Apr 2004:	Fixed bug in event log (requiring update of earlier Plugin versions); doc updates
04 Apr 2004:	Added WHITELIST and BANLIST
21 Mar 2004:	Initial version
CPAN Dependencies:	none
Other Dependencies:	none
Perl Version:	5.005
License:	GPL (GNU General Public License)
Plugin Home:	http://foswiki.org/Extensions/BlackListPlugin
Support:	http://foswiki.org/Support/BlackListPlugin

Related Topics: DefaultPreferences, SitePreferences, Plugins, Google wiki spam directory