express-ntlm

An express middleware to have basic NTLM-authentication in node.js.

> Upgrading from 1.0: The fields for username, domain and workstation have different names now: UserName, DomainName, Workstation.

Active Directory support is heavily inspired by PyAuthenNTLM2.

important notes on (reverse) proxies and NTLM

NTLM is designed for corporate networks without a proxy between the client and the application. It does authorise the TCP connection instead of the HTTP session and with a proxy between, it'll authorise the connection between the proxy and the application and therefore mixing up users if the proxy shares the same connection or "forgetting" users if the proxy suddenly uses a different connection for the same user.

In an early state of this module express-ntlm tried to create a session during the negotiation, which failed (see 50d9ac4) even though RFC6265 makes it clear it MUST be possible: "User agents [...] MUST process Set-Cookie headers contained in other responses (including responses with 400- and 500-level status codes)."

A possible solution to this problem might be to set the keep-alive property in nginx as mentioned in an answer from StackOverflow regarding this issue but it could end in the "multiple-users same-connection"-problem mentioned from another user.

Another option would be to abandon the proxy completely and connect directly to the application on port 80 or build a custom reverse proxy that authenticates the user, creates a session and keeps the session data on a shared store, that is accessible by all applications behind the proxy (e.g. expressjs/session in combination with visionmedia/connect-redis).

install

$ npm install express-ntlm

example usage

var express = require('express'),
    ntlm = require('express-ntlm');

var app = express();

app.use(ntlm({
    debug: function() {
        var args = Array.prototype.slice.apply(arguments);
        console.log.apply(null, args);
    },
    domain: 'MYDOMAIN',
    domaincontroller: 'ldap://myad.example',

    // use different port (default: 389)
    // domaincontroller: 'ldap://myad.example:3899',
}));

app.all('*', function(request, response) {
    response.end(JSON.stringify(request.ntlm)); // {"DomainName":"MYDOMAIN","UserName":"MYUSER","Workstation":"MYWORKSTATION"}
});

app.listen(80);

example with ldaps

var express = require('express'),
    ntlm = require('express-ntlm'),
    fs = require('fs');

var app = express();

app.use(ntlm({
    debug: function() {
        var args = Array.prototype.slice.apply(arguments);
        console.log.apply(null, args);
    },
    domain: 'MYDOMAIN',
    domaincontroller: 'ldaps://myad.example',
    tlsOptions: {
        //trusted certificate authorities (can be extracted from the server with openssh)
        ca: fs.readFileSync('./ca.pem'),
        //tells the tls module not to check the server's certificate (do not use in production)
        //rejectUnauthorized: false,
    }
}));

//same as above
app.all('*', function(request, response) {
    response.end(JSON.stringify(request.ntlm)); // {"DomainName":"MYDOMAIN","UserName":"MYUSER","Workstation":"MYWORKSTATION"}
});

app.listen(80);

without validation

It's not recommended, but it's possible to add NTLM-Authentication without validation. This means you can authenticate without providing valid credentials.

app.use(ntlm());

options

logging (examples)

function() {
    var args = Array.prototype.slice.apply(arguments);
    console.log.apply(null, args);
}

logging to debug (or similiar logging-utilities)

function() {
    var args = Array.prototype.slice.apply(arguments);
    debug.apply(null, args.slice(1)); // slice the prefix away, since debug is already prefixed
}

notes

All NTLM-fields (UserName, DomainName, Workstation) are also available within response.locals.ntlm, which means you can access it through your template engine (e.g. jade or ejs) while rendering (e.g. <%= ntlm.UserName %>).