Express CSRF token validation

Question

I'm having issues with CSRF tokens. When I submit a form, a new XSRF-TOKEN is being generated but I think I'm generating two different tokens, I'm kinda confused. There's also a token called _csrf, so I see two different cookies in developer tools (XSRF-TOKEN and _csrf), _csrf doesn't change after a post.

What I want to do is to generate a new token for each post request and check whether it's valid or not. One thing I know that I should do it for security, but I stuck.

It has been a long day and I'm new into Express and NodeJS.

Here's my current setup.

var express = require('express')
  , passport = require('passport')
  , flash = require('connect-flash')
  , utils = require('./utils')
  , csrf = require('csurf')
  // setup route middlewares
  ,csrfProtection = csrf({ cookie: true })
  , methodOverride = require('method-override')
  , bodyParser = require("body-parser")
  , parseForm = bodyParser.urlencoded({ extended: false })
  , cookieParser = require('cookie-parser')
  , cookieSession = require('cookie-session')
  , LocalStrategy = require('passport-local').Strategy
  , RememberMeStrategy = require('../..').Strategy;


var app = express();

app.set('views', __dirname + '/views');
app.set('view engine', 'ejs');
app.engine('ejs', require('ejs-locals'));
app.use(express.logger());
app.use(express.static(__dirname + '/../../public'));
app.use(cookieParser());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
app.use(methodOverride());
app.use(express.session({ secret: 'keyboard cat' }));
app.use(flash());
// Initialize Passport!  Also use passport.session() middleware, to support
// persistent login sessions (recommended).
app.use(passport.initialize());
app.use(passport.session());
app.use(passport.authenticate('remember-me'));
app.use(app.router);
app.use(csrf());

app.use(function (req, res, next) {
  res.cookie('XSRF-TOKEN', req.csrfToken());
  res.locals.csrftoken = req.csrfToken();
  next();
});

Routes

app.get('/form', csrfProtection, function(req, res) {
  // pass the csrfToken to the view
  res.render('send', { csrfToken: req.csrfToken()});
});

app.post('/process', parseForm, csrfProtection, function(req, res) {
  res.send('data is being processed');
});

send.ejs (/form GET)

<form action="/process" method="POST">
  <input type="hidden" name="_csrf" value="<%= csrfToken %>">

  Favorite color: <input type="text" name="favoriteColor">
  <button type="submit">Submit</button>
</form>

Answer 1

Based on the amount of code you shared, I will mention a few things that don't look quite right to me:

1 . You may need to swap the lines below so that csrf runs before the routes.

app.use(csrf());
app.use(app.router);

2 . The csrftoken setup needs to also be placed before the routes.

app.use(csrf());
app.use(function (req, res, next) {
  res.cookie('XSRF-TOKEN', req.csrfToken());
  res.locals.csrftoken = req.csrfToken();
  next();
});
app.use(app.router);

3 . You'll need to use locals.csrftoken in your form:

<form action="/process" method="POST">
  <input type="hidden" name="_csrf" value="<%= csrftoken %>">

  Favorite color: <input type="text" name="favoriteColor">
  <button type="submit">Submit</button>
</form>