SpamAssassin rule
MIME_BASE64_TEXT
Text hidden in base64
+0.001 points
Raw body test
What MIME_BASE64_TEXT means
Plain text is base64-encoded, which can hide content from simple filters.
The rule's description in SpamAssassin: “Message text disguised using base64 encoding”
How to fix it
Use quoted-printable or 8bit encoding for text parts.
This rule adds almost nothing to the score by itself. It matters only together with other rules.
Does your email trigger MIME_BASE64_TEXT?
Send it to a free test address: we run SpamAssassin, check SPF, DKIM and DMARC and show every rule with a fix.
Open the email spam checkerRelated rules
HTML_FONT_LOW_CONTRASTText color almost matches the background
HTML_IMAGE_ONLY_04Mostly images, almost no text
HTML_IMAGE_ONLY_08Mostly images, little text
HTML_IMAGE_ONLY_12Mostly images, little text
HTML_IMAGE_ONLY_16Many images for the amount of text
HTML_IMAGE_RATIO_02Low text-to-image ratio
HTML_MIME_NO_HTML_TAGHTML part without an <html> tag
HTML_SHORT_LINK_IMG_1Very short HTML with a linked image
MIME_HTML_ONLYHTML only, no plain-text version
Frequently asked questions
What does MIME_BASE64_TEXT mean?
Plain text is base64-encoded, which can hide content from simple filters.
How do I fix MIME_BASE64_TEXT?
Use quoted-printable or 8bit encoding for text parts.
How many points does MIME_BASE64_TEXT add?
0.001 points in the default SpamAssassin ruleset (network tests on, Bayes off). A message is treated as spam from 5.0 points. Mail servers can change scores locally.