Starting from Multiloginapp 1.4.3, when you enable the ‘Mask Fonts’ feature in Stealthfox, the following things will happen:
- Multiloginapp will take the list of all of the fonts installed on your PC,
- generate a random list out of them, and
- inject this list into the browser profile you are launching.
This will make the browser profile more unique and help avoid being fingerprinted by fonts enumeration.
Due to the nature of this font randomization, sometimes the websites may try to display text in fonts, which were not generated in that specific browser profile. In this case, a pre-defined fallback font will be used.
You can define the fallback font in the setting of the browser profile:
Some fingerprinting tests may revolve around specific fonts. In case one of these fingerprinting fonts is missing, the specified fallback font will be used. This is why it’s highly recommended to have the same fonts installed on all PC’s, from which the browser profile will be accessed.
In order to avoid having varying fingerprinting results due to the different fallback font installed on multiple PCs, you have the option to forbid the start of the browser profile, if the fallback font is missing. This option can be configured in the settings of the browser profile:
After enabling this feature, the browser profile won’t open, if the launching PC does not have the specified fall back font installed and the following error will be displayed: