email headers

notes.md

base64 abuse

• https://www.opswat.com/blog/how-base64-encoding-opens-the-door-for-malware

html evasion techniques

• https://cybersecuritynews.com/html-functions-exploited-to-bypass-email-security-filters/

html smuggling

• https://blog.talosintelligence.com/hidden-between-the-tags-insights-into-evasion-techniques-in-html-smuggling/

quoted-printable

• https://en.wikipedia.org/wiki/Quoted-printable
• https://www.gnu.org/software/emacs/manual/html_node/emacs-mime/qp.html

bimi

• https://powerdmarc.com/what-is-a-bimi-selector-header/
• https://en.wikipedia.org/wiki/Brand_Indicators_for_Message_Identification

feedback-id

• https://mailtrap.io/blog/email-feedback-loop/

x-antiabuse

• https://security.stackexchange.com/questions/67036/how-to-report-abuse-spam-with-x-antiabuse-header-which-was-added-to-track-abuse

antispam message headers

• https://learn.microsoft.com/en-us/defender-office-365/message-headers-eop-mdo

x-spam-*

• https://www.physicsforums.com/threads/problem-with-pfs-email-configuration.1015637/
• https://www.lamphost.com/Knowledge_Base/What_headers_are_added_to_emails_that_are_scanned_by_SpamAssassintm

sender authenticaion

• https://www.fastmail.help/hc/en-us/articles/1500000280461-Sender-authentication
• https://datatracker.ietf.org/doc/html/rfc7001

authentication-results

• https://inventivehq.com/blog/email-authentication-results-header-explained
• https://dmarceye.com/glossary/authentication-results

dkim

• https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail
• https://powerdmarc.com/what-is-dkim-signature/
• https://ediscoverychannel.com/2021/02/28/nothings-dkimpossible-manually-verifying-dkim-a-ctf-solution-and-implications/
• https://github.com/kmille/dkim-verify
• https://debugging.works/blog/verify-dkim-signature/

misc

• https://www.fastmail.com/blog/spf-dkim-dmarc/
• https://github.com/fastmail/authentication_milter
• https://dev.to/sweego/email-authentication-understanding-headers-1pn1
• https://www.sweego.io/channel/email/email-authentication-analyze-your-email-header
• https://www.ranum.com/security/computer_security/editorials/dumb/