Dear jo , this is my first attempt.
From the client side it seems to work,
I can telnet , insert my user , then it request my password and it seems similar to original shell.
But when trying from legitimate telnet client it does not.
Im also thinking the idea of creating a real linux server with telnet login and then redirect telnet daemon to a custom script (like a pseudo shell). I need to find out all pieces and make them work togheter.
This is my perl telnet server:
#!/usr/bin/perl -w
use IO::Socket;
use Net::hostent; # for OO version of gethostbyaddr
$PORT = 9000; # pick something not in use
$prompt="MA5680T>";
$server = IO::Socket::INET->new( Proto => 'tcp',
LocalPort => $PORT,
Listen => SOMAXCONN,
Reuse => 1);
die "can't setup server" unless $server;
print "[Server $0 accepting clients]\n";
while ($client = $server->accept()) {
$client->autoflush(1);
#print $client "Welcome to $0; type help for command list.\n";
#$hostinfo = gethostbyaddr($client->peeraddr);
#printf "[Connect from %s]\n", $hostinfo->name || $client->peerhost
+;
print $client "\n";
print $client "Warning: Telnet is not a secure protocol, and it is
+recommended to use Stelnet.";
print $client "\n";
print $client "\n";
print $client ">>User name:";
while ( <$client>) {
next unless /\S/; # blank line
print "\nlinea :$_";
if (/quit|exit/i) { last;
+ }
elsif (/leo/i) { printf $client "\n>>User password:"; }
elsif (/password/i) { printf $client "\n$prompt"; }
else {
print $client "\n$prompt";
}
} continue {
#print $client $prompt;
}
close $client;
}
Regards,
Leandro | [reply]
[d/l] |
Though this is a rudimentary server, it is not a telnet server.
It depends on the client if it is willing to communicate with such a non-telnet endpoint.
I think it would be easier to replace the login shell of the user with some interceptor.
That way the application would talk to a real telnetd, which - after authenticating the client - will connect it to your login shell replacement, where you may perform anything you like.
Greetings,
-jo
$gryYup$d0ylprbpriprrYpkJl2xyl~rzg??P~5lp2hyl0p$
| [reply] |
Thanks for your idea.
I will work on that.
Regards.
Leandro.
| [reply] |
