Note: while the use-case described is about using submodules within a project, the same applies to a normal git clone of a repository over HTTP.
I have
On Windows, if you don't want to put your password in .gitconfig in the plain text, you can use
It authenticates you against normal or even Windows NTLM proxy and starts localhost-proxy without authentication.
In order to get it run:
Point git to your new localhost proxy:
[http]
proxy = http://localhost:3128 # change port as necessary