Edgewall Software

Version 66 (modified by Dirk Stöcker, 12 years ago) ( diff )

Some more notes

Trac Spam Filtering

  1. Supported Internal Filtering Strategies
    1. Regular Expressions
    2. Regular Expressions for IP
    3. IP Throttling
    4. Captcha
    5. Bayes
  2. Supported External Filtering Strategies
    1. IP Blacklisting
    2. Akismet
    3. TypePad
    4. Defensio
    5. StopForumSpam
    6. LinkSleeve
    7. BlogSpam
    8. HTTP:BL
    9. SpamBusted
    10. BotScout
    11. FSpamList
    12. SpamWipe
  3. Get the Plugin
  4. Enabling the Plugin
  5. Further Reading
  6. Known Issues
  7. Requirements

This plugin allows different ways to reject contributions that contain spam. This plugin requires Trac release 0.12. The plugin code for versions before 0.12 isn't updated any more.

The spamfilter plugin has many options, but most of them are optional. Basically installing is enough to have a basic spam protection. But there are some things which may be helpful (in order of importance):

  • Train bayes database (using the entries of the log) to activate that filter and reach good performance (bayes filter needs spambayes installed!)
  • Setup BadContent page containing regular expressions to filter
  • Get API keys for Akismet, TypePad, and/or HTTP:BL to use external services
  • Activate captcha rejection handler to improve user treatment (may need reCAPTCHA access when that method should be used)
  • Finetune the karma settings and parameters for your system (e.g. you may increase karma for good trained bayes filters or stop trusting registered users)
  • If necessary get API keys for other services and activate them

WebAdmin is used for configuration, monitoring, and training. For monitoring and training purposes, it optionally logs all activity to a table in the database. Upgrading the environment is necessary to install the database table required for this logging.

Supported Internal Filtering Strategies

The individual strategies assign scores (“karma”) to submitted content, and the total karma determines whether a submission is rejected or not.

Regular Expressions

The regex​ filter reads a list of regular expressions from a wiki page named “BadContent”, each regular expression being on a separate line inside the first code block on the page, using the ​Python syntax for regular expressions.

If any of those regular expressions matches the submitted content, the submission will be rejected.

Regular Expressions for IP

The ip_regex​ filter reads a list of regular expressions from a wiki page named “BadIP”, each regular expression being on a separate line inside the first code block on the page, using the ​Python syntax for regular expressions.

If any of those regular expressions matches the submitters IP, the submission will be rejected.

Regular expressions are much too powerful for the simple task of matching an IP or IP range, but to keep things simple for users the design is equal to the content based regular expressions. You simple can specify full IPV4 addresses even if the dot has special meaning, as the match will work correctly. Only when matching partial addresses more care is needed.

IP Throttling

The ip_throttle​ filter limits the number of posts per hour allowed from a single IP.

The maximum number of posts per hour is configured in trac.ini: 

[spam-filter]
max_posts_by_ip = 5

When this limit is exceeded, the filter starts giving submissions negative karma as specified by the ip_throttle_karma option.

Captcha

Support to have CAPTCHA-style "human" verification is integrated. Captcha usage is configured in the 'Captcha' administration page.

Currently three captcha types are supported:

Bayes

The Bayes filter is a very powerful tool when used properly. Following are a few guidelines how to use and train the filter to get good results:

  • When beginning, the filter needs a minimum amount of 25 entries for HAM (useful entries) and also for SPAM (advertising). Simply train every submission you get until these limits are reached.
  • The training is done in Administration Menu "Spam Filtering / Monitoring". You have following buttons
    • Mark selected as Spam - Mark the entries as SPAM and train them in Bayes database
    • Mark selected as Ham - Mark the entries as HAM and train them in Bayes database
    • Delete selected - remove entry without training
    • Delete selected as Spam - Mark the entries as SPAM and train them in Bayes database, remove them afterwards
    • Delete selected as Ham - Mark the entries as HAM and train them in Bayes database, remove them afterwards
    • When JavaScript is enabled a number of check boxes is available, which help selecting entries
  • Rules for a good trained database are:
    • Don't train the same stuff multiple times
    • HAM and SPAM count should be nearly equal (In reality you will have more SPAM, but a factor of 1 to 5 should be the maximum)
    • Restart from scratch when results are poor
    • It is hard to get rid of training errors, so be carefully
    • See ​SpamBayes pages for more details.
  • Strategy for Trac usage:
    • Use the Delete selected as Spam and Delete selected as Ham
    • Remove every strange entry (e.g. SandBox stuff) using Delete selected
    • Train every valid HAM entry (or database will get unbalanced)
    • Be sure to train every error: Rejected user submissions as well as undetected SPAM
    • Train every SPAM entry with a score below 90% (at the beginning you may train everything not 100%)
    • Delete SPAM entries with high score (100% in any case, after beginning phase everything above 90%)
    • When in doubt if SPAM or HAM, delete entry
  • NOTE: When Akismet, Defensio, BlogSpam or TypePad are activated, then training will send the entries also to these services.
  • If you append the parameter "num" with values between 5 and 150 at monitoring page url.../admin/spamfilter/monitor?num=100 you can show more entries, but don't train very large dataset at once.

Supported External Filtering Strategies

IP Blacklisting

The ip_blacklist​ filter uses the third-party Python library ​dnspython to make DNS requests to a configurable list of IP blacklist servers.

See e.g. ​SpamLinks DNS Lists for a list of DNS based blacklists. A blacklist usable for this filter must return an IP for listed entries and no IP (NXDOMAIN) for unlisted entries.

NOTE: Submitters IP is sent to configured servers.

Akismet

The Akismet​ filter uses the ​Akismet web service to check content for possible spam.

The use of this filter requires a ​Wordpress API key. The API key is configured in the 'External' administration page.

NOTE: Submitted content is sent to Akismet servers. Don't use this in private environments.

TypePad

The TypePad AntiSpam​ filter uses the ​Typepad web service to check content for possible spam.

The use of this filter requires a API key. The API key is configured in the 'External' administration page.

NOTE: Submitted content is sent to TypePad servers. Don't use this in private environments.

Defensio

The Defensio​ filter uses the ​Defensio web service to check content for possible spam.

The use of this filter requires an API key. The API key is configured in the 'External' administration page.

NOTE: Submitted content is sent to Defensio servers. Don't use this in private environments.

StopForumSpam

The StopForumSpam​ filter uses the ​StopForumSpam web service to check content for possible spam. This services tests IP, username and/or email address.

Training this filter requires an API key. The API key is configured in the 'External' administration page.

NOTE: Submitted username and IP is sent to StopForumSpam servers. Don't use this in private environments.

LinkSleeve

The LinkSleeve​ filter uses the ​LinkSleeve web service to check content for possible spam.

NOTE: Submitted content is sent to LinkSleeve servers. Don't use this in private environments.

BlogSpam

The BlogSpam​ filter uses the ​BlogSpam web service to check content for possible spam.

This service includes also DNS checks and services identical to the checks in this plugin. Be sure to set proper karma or these checks are counted twice. You also can disable individual checks in preferences.

NOTE: Submitted content is sent to BlogSpam servers. Don't use this in private environments.

HTTP:BL

The HTTP:BL​ filter uses the ​Project HoneyPot HTTP:BL web service to check content for possible spam.

The use of this filter requires a ​HTTP:BL API key. The API key is configured in the 'External' administration page.

NOTE: Submitters IP is sent to HTTP:BL servers.

SpamBusted

The SpamBusted​ filter uses the ​SpamBusted web service to check content for possible spam. This services tests IP, username and/or email address.

Training this filter requires an API key. The API key is configured in the 'External' administration page.

NOTE: Submitted username and IP is sent to SpamBusted servers. Don't use this in private environments.

BotScout

The BotScout​ filter uses the ​BotScout web service to check content for possible spam. This services tests IP, username and/or email address.

Using this filter requires an API key. The API key is configured in the 'External' administration page.

NOTE: Submitted username and IP is sent to BotScout servers. Don't use this in private environments.

FSpamList

The FSpamList​ filter uses the ​FSpamList web service to check content for possible spam. This services tests IP, username and/or email address.

Using this filter requires an API key. The API key is configured in the 'External' administration page.

NOTE: Submitted username and IP is sent to !FSpamList servers. Don't use this in private environments.

SpamWipe

The SpamWipe​ filter uses the ​SpamWipe web service to check content for possible spam.

The use of this filter requires a API key. The API key is configured in the 'External' administration page.

NOTE: Submitted content is sent to SpamWipe servers. Don't use this in private environments.

Get the Plugin

See the Trac plugin requirements for instructions on installing setuptools. Setuptools includes the easy_install application which you can use to install the SpamFilter: 

easy_install TracSpamFilter

You can also obtain the code from the Trac Subversion repository: 

svn co http://svn.edgewall.com/repos/trac/plugins/0.12/spam-filter-captcha

or download ​zipped source.

See TracPlugins for instructions on building and installing plugins.

You can browse the source in Trac​.

​This is a link for setuptools to find the SVN download

Enabling the Plugin

If you install the plugin globally (as described here), you'll also need to enable it in the web administration or in trac.ini as follows: 

[components]
tracspamfilter.* = enabled

You can disable individual strategies:

  • Disable the corresponding class in plugin handling
  • Set karma to 0
  • External services requiring API key are disabled without key
  • All external services can be disabled in 'External' section (completely and only for training)

Further Reading

Known Issues

  • Attention: The 1.7 series of dnspython causes a massive slowdown of whole Trac. Use 1.6.x or 1.8.x.

#10035
Possibility to apply rejected changes from log

Requirements

  • The modules for IP blacklistening und HTTP:BL need ​dnspython installed. Install "setuptools" based on the Trac plugin requirements, then you can run "easy_install dnspython" to automatically download and install the package.
  • Attention: The 1.7 series of dnspython causes a massive slowdown of whole Trac. Use 1.6.x or 1.8.x.
  • The ImageCaptcha requires python-imaging to work.
  • Bayes filtering needs spambayes software installed.

See also: TracPlugins, PluginList

Note: See TracWiki for help on using the wiki.