I've tried to search through stackoverflow for a similar question but most people are asking about the client-side of the NTLMv2 protocol. I'm implementing a proxy that is performing the server-side of the protocol to authenticate users connecting to the proxy. I've coded a lot of the protocol but I'm now stuck because the documentation that should take me further is difficult to understand.
This is the best documentation I've found so far: http://www.innovation.ch/personal/ronald/ntlm.html, but how to deal with the LM and NT responses is oblivious to me.
The proxy is located on an application server. The domain server is a different machine.
Example code for the node proxy:
var http = require('http')
, request = require('request')
, ProxyAuth = require('./proxyAuth');
function handlerProxy(req, res) {
ProxyAuth.authorize(req, res);
var options = {
url: req.url,
method: req.method,
headers: req.headers
}
req.pipe(request(options)).pipe(res)
}
var server = http.createServer(handlerProxy);
server.listen(3000, function(){
console.log('Express server listening on port ' + 3000);
});
ProxyAuth.js code:
ProxyAuth = {
parseType3Msg: function(buf) {
var lmlen = buf.readUInt16LE(12);
var lmoff = buf.readUInt16LE(16);
var ntlen = buf.readUInt16LE(20);
var ntoff = buf.readUInt16LE(24);
var dlen = buf.readUInt16LE(28);
var doff = buf.readUInt16LE(32);
var ulen = buf.readUInt16LE(36);
var uoff = buf.readUInt16LE(40);
var hlen = buf.readUInt16LE(44);
var hoff = buf.readUInt16LE(48);
var domain = buf.slice(doff, doff+dlen).toString('utf8');
var user = buf.slice(uoff, uoff+ulen).toString('utf8');
var host = buf.slice(hoff, hoff+hlen).toString('utf8');
var lmresp = buf.slice(lmoff, lmoff+lmlen).toString('utf8');
var ntresp = buf.slice(ntoff, ntoff+ntlen).toString('utf8');
console.log(user, lmresp, ntresp);
/* NOW WHAT DO I DO? */
},
authorize: function(req, res) {
var auth = req.headers['authorization'];
if (!auth) {
res.writeHead(401, {
'WWW-Authenticate': 'NTLM',
});
res.end('<html><body>Proxy Authentication Required</body></html>');
}
else if(auth) {
var header = auth.split(' ');
var buf = new Buffer(header[1], 'base64');
var msg = buf.toString('utf8');
console.log("Decoded", msg);
if (header[0] == "NTLM") {
if (msg.substring(0,8) != "NTLMSSP\x00") {
res.writeHead(401, {
'WWW-Authenticate': 'NTLM',
});
res.end('<html><body>Header not recognized</body></html>');
}
// Type 1 message
if (msg[8] == "\x01") {
console.log(buf.toString('hex'));
var challenge = require('crypto').randomBytes(8);
var type2msg = "NTLMSSP\x00"+
"\x02\x00\x00\x00"+ // 8 message type
"\x00\x00\x00\x00"+ // 12 target name len/alloc
"\x00\x00\x00\x00"+ // 16 target name offset
"\x01\x82\x00\x00"+ // 20 flags
challenge.toString('utf8')+ // 24 challenge
"\x00\x00\x00\x00\x00\x00\x00\x00"+ // 32 context
"\x00\x00\x00\x00\x00\x00\x00\x00"; // 40 target info len/alloc/offset
type2msg = new Buffer(type2msg).toString('base64');
res.writeHead(401, {
'WWW-Authenticate': 'NTLM '+type2msg.trim(),
});
res.end();
}
else if (msg[8] == "\x03") {
console.log(buf.toString('hex'));
ProxyAuth.parseType3Msg(buf);
/* NOW WHAT DO I DO? */
}
}
else if (header[0] == "Basic") {
}
}
}
};
module.exports = ProxyAuth;
The /* NOW WHAT DO I DO? */ comment specifies where I am stuck.
I hope I put enough information there, but let me know if anything else is needed.
