Windows 10 has a mode to disable font-loading from external sources, such as emails when the font has to be fetched outside of the installed fonts. This feature is meant to prevent from attacks coming from untrusted fonts.
The icons in our UI are made with a font file. We used icomoon, but if Windows 10 is set up with the same set similar to projects like fontawesome. We use custom fonts with icomoon.
However, this brings problems with displaying our UI in Firefox and IE11.
How can we solve this problem? The Microsoft recommended way it is to either install the font in the system or whitelist the application that needs that font.
We thought of three ways, at least initially:
- Install the font
- Use an SVG file
- Propose the customer to whitelist the browser to let them use our app. This is the last option as it would make the setting less secure.