I can't connect to openvpn

I’m using the Parrot HTB version, when I try to sudo openvpn filename.ovpn I get this error:

2023-11-19 18:07:25 --cipher is not set. Previous OpenVPN version defaulted to BF-CBC as fallback when cipher negotiation failed in this case. If you need this fallback please add ‘–data-ciphers-fallback BF-CBC’ to your configuration and/or add BF-CBC to --data-ciphers.

2023-11-19 18:07:25 OpenVPN 2.5.1 x86_64-pc-linux-gnu [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [PKCS11] [MH/PKTINFO] [AEAD] built on May 14 2021

If I add --cipher AES-256-CBC in the config file then I get this error:

2023-11-19 18:08:12 OpenVPN 2.5.1 x86_64-pc-linux-gnu [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [PKCS11] [MH/PKTINFO] [AEAD] built on May 14 2021

2023-11-19 18:08:12 library versions: OpenSSL 1.1.1w 11 Sep 2023, LZO 2.10

2023-11-19 18:08:12 Outgoing Control Channel Authentication: Using 512 bit message hash ‘SHA512’ for HMAC authentication

2023-11-19 18:08:12 Incoming Control Channel Authentication: Using 512 bit message hash

‘SHA512’ for HMAC authentication

023-11-19 19:17:02 TLS_ERROR: BIO read tls_read_plaintext error

2023-11-19 19:17:02 TLS Error: TLS object → incoming plaintext read error

2023-11-19 19:17:02 TLS Error: TLS handshake failed

2023-11-19 19:17:02 SIGUSR1[soft,tls-error] received, process restarting

2023-11-19 19:17:02 Restart pause, 5 second(s)

It’s seems that the error messages suggest that the OpenVPN client is not finding a compatible encryption cipher based on your current configuration.

Try…

sudo openvpn <path to .ovpn file> --cipher BFC-CBC

My next steps would be:

sudo apt remove openvpn Sudo apt install openvpn

Download new .ovpn file from HTB