OpenVPN SOCKS5 username and password authentication

[g4lvanix]

Hello!

I am trying to set up OpenVPN in conjunction with obfs4proxy to obfuscate the traffic between the OpenVPN clients and the server.

obfs4proxy exposes a SOCKS5 proxy and requires username and password authentication, i.e. the OpenVPN client connects through the obfs4proxy SOCKS proxy to the OpenVPN server.
In order to do this I need to use a single ASCII NUL character as the password.

I have already tried to use the URL escaped NUL character %00 on the second line of the auth file --> did not work

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$ hexdump -C socks_auth
00000000  75 73 65 72 6e 61 6d 65  0a 25 30 30 0a           |username.%00.|
0000000d

After that I tried manually appending a 0 byte to the text file instead --> again this did not work

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$ hexdump -C socks_auth
00000000  75 73 65 72 6e 61 6d 65  0a 00                    |username..|
0000000a

Is there a way to tell OpenVPN to use a single NUL character as the password to authenticate to a SOCKS5 proxy?

Thank you!

[g4lvanix]

For future reference:

I have found that using a simple ASCII 0 character works just as well, i.e. a file like this

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username
0