SpamAssassin 4.0 new features
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The document outlines the new features in SpamAssassin 4.0, which began development in 2015 to enhance the UTF-8 parser and includes improvements such as better handling of non-English emails and the addition of various plugins for attachment processing and URL decoding. It also discusses updates to sa-update with new options, the implementation of ARC signatures for email validation, and changes in DMARC policies to protect domains. Additionally, some keywords have been made more inclusive, with plans for deprecated terms to be removed in the future.
SpamAssassin 4.0 new features
- 1. New features in SpamAssassin 4.0 Giovanni Bechis <gbechis@apache.org> 2022.07.30
- 2. SpamAssassin 4.0 dev story • 4.0 branch started on 2015 as a copy of 3.4.1 version • 4.0 branch has started primarily to improve utf-8 parser • While developing on 4.0 branch 5 minor versions have been released • Most recent SpamAssassin released version is 3.4.6 released on 04/12/2021
- 3. UTF8 support • With UTF8 and UTF16 support SpamAssassin can easily block spam in different languages
- 4. UTF8 support # Match a “ ” on the email Subject 📆 header EMOJI_CAL Subject =~ /xf0x9fx93x86/i
- 5. Bayes improvements • It’s now possible to skip common words used in 15 different languages to improve Bayes algorithm on non- english emails
- 6. Bayes improvements # Danish stopwords bayes_stopword_dk (?^:(?:a(?:lle|nden)|bl(?:ev| iver?)|d(?:e(?:nne|res|tte)|isse)|e(?:fter|ller)| h(?:a(?:ns|v(?:de|e))|endes?|v(?:ad|is|or))|ikke| kunne|m(?:ange|eget|ine)|nog(?:et|le)|o(?:gsxc3 xa5|ver)|s(?:elv|ine|k(?:al|ulle)|xc3xa5dan)| under|v(?:ille|xc3xa6ret?)))
- 7. ExtractText plugin • ExtractText.pm is a plugin that extract text from attachments using external softwares
- 8. ExtractText plugin extracttext_external tesseract {OMP_THREAD_LIMIT=1} /usr/local/bin/tesseract -c page_separator= {} - extracttext_use tesseract .bmp .jpg .png .tif extracttext_external xls2txt /usr/local/scripts/xls2txt.pl -u -i {} extracttext_use xls2txt .xls application/(?:vnd.?)?ms-?excel.*
- 9. OLEVBMacro plugin • OLEVBMacro plugin can now extract uris from Office documents metadata
- 10. Short urls • DecodeshortURLs is a plugin that checks the url shorteners target
- 11. Short urls Ifplugin Mail::SpamAssassin::Plugin::DecodeShortURLs url_shortener .short.gy url_shortener bit.ly body HAS_SHORT_URL eval:short_url() score HAS_SHORT_URL 0.01 endif
- 12. Captured tags • Captured tags can be used in other rules as a matching string
- 13. Captured tags if can(Mail::SpamAssassin::Conf::feature_capture_rules) header __FROM_NAME From:name =~ /(?<FROM_NAME>w+)/ header FROM_NAME_SUBJ Subject =~ /b%{FROM_NAME}b/i endif
- 14. sa-update(1) improvements • sa-update(1) has been improved with new options: --forcemirror --score-multiplier --score-limit
- 15. sa-update(1) improvements • --forcemirror forces sa-update to use a specific mirror server • --score-multiplier adjust all scores from update channel, multiply with given value • --score-limit adjust all scores from update channel, limit to given value
- 16. ARC Signatures • ARC signatures are used to validate an email when the email's SPF and DKIM records are rendered invalid by an intermediate server
- 17. DMARC policies • DMARC policies give email domain owners the ability to protect their domain from unauthorized use
- 18. DMARC policies ifplugin Mail::SpamAssassin::Plugin::Dmarc # dmarc_save_reports 1 header DMARC_PASS eval:check_dmarc_pass() describe DMARC_PASS DMARC pass policy priority DMARC_PASS 500 tflags DMARC_PASS net nice reuse DMARC_PASS endif
- 19. Inclusion changes Some keywords have been changed by using more inclusive words. • whitelist -> welcomelist • blacklist -> blocklist Old keywords will continue to work until SpamAssassin 4.1 will be released