Avatar for Username

Sök i support

Akta dig för supportbedrägerier: Vi kommer aldrig att be dig att ringa eller skicka ett sms till ett telefonnummer eller dela personlig information. Rapportera misstänkt aktivitet med alternativet "Rapportera missbruk".

Läs mer

Denna tråd har arkiverats. Ställ en ny fråga om du behöver hjälp.

Certain emails appear with non-standard fonts in headers

  • 1 svar
  • 1 har detta problem
  • 1 visning
  • Senaste svar av Zenos

Aimhere
Aimhere
more options

Lately, I've been receiving a few "spam" emails where the text of the message headers ("From" and "Subject", in particular) appears in a non-standard font (e.g. different from all other plaintext in Thunderbird). I didn't think such a thing was even possible within email headers.

Looking at the message source (Ctrl-U), it appears the "From" and "Subject" headers are being encoded in UTF-8.

Is this some kind of attempt by the sender to bypass or trick anti-spam filters?

Note: attached pic has the text highlighted in yellow.

Lately, I've been receiving a few "spam" emails where the text of the message headers ("From" and "Subject", in particular) appears in a non-standard font (e.g. different from all other plaintext in Thunderbird). I didn't think such a thing was even possible within email headers. Looking at the message source (Ctrl-U), it appears the "From" and "Subject" headers are being encoded in UTF-8. Is this some kind of attempt by the sender to bypass or trick anti-spam filters? Note: attached pic has the text highlighted in yellow.
Bifogade skärmdumpar

Alla svar (1)

Zenos
Zenos
more options

Yes, UTF-8 can be used in subject lines, and yes, it can make some spam filtering harder work.

The legitimate intention is to allow non-Latin character sets to be used in subject lines and addresses. One minor form of abuse (IMHO) is using it to insert icons into subject lines. This is a typical example, from a travel company who use it to insert a calendar icon into the subject line.

Subject: =?UTF-8?B?8J+ThSBDaHJpcywgaXMgaXQgdGltZSBmb3IgeW91ciBuZXh0IHRyaXA/?=

As a side effect, it's now non-trivial to tell what the message is about, at least when looking at the source.

Ändrad av Zenos