I receive a lot of spam email (probably from recent breaches). A lot of them contain text that looks a lot like the below text:

enter image description here

Why do they contain such weird characters? Is this part of an exploit? Is this to mislead spam filters? Or is it for a different reason?

  • That's probably an encoding error, using the wrong character set to display e.g. Windows-1252. If you paste the actual text rather than using an image, I could try transcoding it to Unicode equivalents. If you paste the actual raw .eml content (with headers) in a code block, we might be better equipped to speculate on the email.
    – Adam Katz
    Commented Jul 29, 2019 at 21:04
  • @AdamKatz Once I get home I'll see what I can do. I use Outlook so I'll have to first figure out how to export these mails as EML
    – Nzall
    Commented Jul 30, 2019 at 7:15
  • 2
    I see localized spam from some regions where they basically assume that everyone is using the same character set and so it doesn't have to be explicitly stated, in violation of pertinent email RFCs. Maybe a client which is popular in the region displays it like they expected, and they don't care, or simply didn't notice that it's broken for other recipients.
    – tripleee
    Commented Oct 31, 2019 at 7:29

1 Answer 1


Usually those are UTF8 sequences that resemble other characters, without being them.

For example 𝒕𝒉𝒊𝒔 𝒔𝒕𝒓𝒊𝒏𝒈 is not the text "this string", and therefore does not trigger UCE detectors as spam, while you probably read it as "this string", as the sender intended.

On the other hand, it is weirdly encoded, so it can happen that it is decoded incorrectly. And "𝒕𝒉𝒊𝒔 𝒔𝒕𝒓𝒊𝒏𝒈" becomes ����������� or other mojibake.

  • If you are curious: These are "Maths Alphanumeric Symbols" starting at U1D400. Four byte UTF-8. 𝖙𝖍𝖎𝖘 𝖘𝖙𝖗𝖎𝖓𝖌 is nearby.
    – gnasher729
    Commented Oct 2, 2023 at 10:01

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