While working on a project i came across an error while trying to join an IRC server who had SASL Authentication with a custom-self-made client.
Note: With the official mIRC client it works just fine.
IMPORTANT NOTE: I DIDNT STUDY ANYTHING ABOUT SASL TLS AUTHENTICATION/ENCRYPTION AND THE DESCRIPTION I PROVIDE BELOW ARE WHAT I THOUGHT AT THE TIME IT WAS. aka PURE GUESSING WORK
And here it started...
The mIRC debug:
Description:
The client SENDS BEFORE ANYTHING the CAP LS command (In my head the CAP LS command was more like a header where it was indicatubg the SASL Authentication Request.)
SERVER: Command: CAP *TOKEN* LS :multi-prefix sasl tls
Description:
The server assigns to the client a random generated token *which is never used* and awaits for a response
CLIENT:
Command: CAP REQ :multi-prefixDescription:
We respond back to the server with the CAP REQ :multi-prefix command
SERVER: Command: PRIVMSG *NICKNAME* :VERSION
Description:
The server send a Private Message and asks for the client version
CLIENT:
Command: NOTICE *SERVER ADDRESS* :VERSION mIRC v7.43 <--- Here im just using the original mIRC version signatureDescription:
We respond back to the server via PM using the NOTICE command and giving a fake client version "signature"
SERVER: Command: CAP *NICKNAME* ACK :multi-prefix
Description:
Last Authentication step , server asks for the client to confirm the end of auth. by sending the CAP END command.
CLIENT:
Command: CAP ENDDescription:
We respond back to the server CAP END to end the authentication session
C# (Command Line Code):
String token = buf.Split(' ')[2];
if (buf.Split(' ')[1] == "CAP")
{
Console.Write("Token=" + token + "\n");
//Stage 1 AUTHENTICATION
if (buf.Split(' ')[1] == "CAP" && buf.Split(' ')[2] == token && buf.Split(' ')[3] == "LS")
{
output.Write("CAP REQ :multi-prefix " + "\r\n");
Console.Write("Client: CAP REQ :multi-prefix SENT" + "\n");
}
else if (buf.Split(' ')[1] == "CAP" && buf.Split(' ')[2] == nick)
{
output.Write("CAP END " + "\r\n");
Console.Write("Client: CAP END SENT" + "\n");
}
output.Flush();
}
if (buf.Split(' ')[1] == "PRIVMSG")
{
output.Write("NOTICE x01.mirc.com.gr : VERSION mIRC v7.43 ");
Console.Write("Client: PRIVMSG VERSION SENT" + "\n");
output.Flush();
}
