Let Firefox automatically accept "authentication required" dialogue

When accessing sites at my work I get various "authentication required" dialogues, i.e. from the intranet proxy server. Firefox does remember the username/password but I have to click the dialogue all the time; sometimes multiple times per site. Is there a way to make Firefox do this all automatically?

Afaik there's no NTLM or other advanced protocols in place.

Answer

Do note that, accepting all HTTP authentication dialogs automatically can be risky, because then you don't know when you have sent your credentials and when you didn't.

Good news is that there is a plugin for that: AutoAuth.

AutoAuth automatically submits HTTP authentication dialogs when you’ve chosen to have the browser save your login information. (If you’ve already told the browser what your username and password are, and you’ve told it to remember that username and password, why not just have it automatically submit it instead of asking you each time?)