Blessed Kobold Letters, Who Rewrote the Letter

Patron of HTML emails, content that changes after sending, and mischievous goblins.

Life

On 31 March 2024 Konstantin Weddige of Lutra Security described Kobold Letters. Using CSS stylesheets in HTML emails, a message could show one text when received and a different text after being forwarded: the content changed with the context, like a goblin rewriting the letter when you look away. More a presentation trick than a single product's bug, handy for deception and phishing.

Prayer

O Blessed Kobold Letters, who changes the words when I turn away, let our emails always say the same thing. Amen.

How to celebrate

Celebrated by limiting CSS in mail clients and not blindly trusting the text of a forwarded email.

A letter that changes face means a goblin at work.