Firefox Add Ons disabled – Certificate to blame

The Super-GAU for technology providers. A process does not run perfectly and then nothing works anymore. This happened to Mozilla with a certificate. A certificate was not renewed and there were problems with all Firefox add-ons. The certificate crash caused a lot of excitement. We explain what happened, what certificates are and if the problem is fixed.

Certificate deactivates Add Ons

A lot of add-ons didn’t work anymore after 04.05.2019. They were no longer correctly signed and were marked as “malicious” and could not be downloaded. The first person in years to surf the Internet without an activated ad blocker probably noticed the certificate crash the fastest. What are certificates and why are they so important for the modern Internet?

Certificate course

Digital certificates are an integral part of the modern Internet. They provide cryptographic keys that are used for signing and encrypting. The green lock, which also indicates on this page that the page is encrypted, would be much rarer to find without digital certificates. The issuing of such a certificate is the responsibility of the certification authority (CA). The CA issues a global “root” certificate which certifies the identity and trustworthiness of the CA. With the help of this trust anchor, intermediate certificates are issued that are necessary for the operation of a trustworthy certificate infrastructure. Any number of intermediate certificates can be issued up to the trust anchor, and each certificate contains the trust in the CA. If this intermediate certificate expires, as with Mozilla, the trustworthiness cannot be guaranteed up to the trust anchor and a certificate crash occurs. Due to this error, the add-ons could no longer be used with Mozilla.




And now?

The good news is: Mozilla has now released a current browser version that solves the problem. In the meantime, there have been different workarounds, for example changes in configurations. If add-ons have been completely uninstalled in the meantime, users will have to reinstall the add-ons themselves. This is not done by the update.
Firefox Add Ons disabled – certificate guilty
If you want to know more about which Add Ons you can use for increased privacy and security, please ask us for a Live-Hacking without obligation.


Sevencast – der IT-Security Podcast

Von unterwegs, im Büro oder zu Hause hören und auf dem aktuellen Stand bleiben!

Sevencast bei Spotify
Sevencast bei Apple Podcast
Sevencast bei Overcast


Leave a Comment