express-ntlm

library2.7.0jsnpmunverified

Express middleware for NTLM authentication in Node.js. Current stable version 2.7.0. Maintained as of 2023. It provides NTLM authentication for Express apps, supporting both NTLMv1 and NTLMv2, with optional LDAP validation. Compared to alternatives like passport-ntlm, express-ntlm is simpler and does not require Passport.js. It handles NTLM negotiation, extracts user info (username, domain, workstation), and can validate against Active Directory via LDAP. Known issues with proxies and multiple users on same connection.

auth-security web-framework

npm install express-ntlm

github ↗package ↗

INSTALL

IMPORT

SIG · EXPRESS-NTLM

express-ntlm

auth-securityjavascriptv2.7.0

Install

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Import

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Disk

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Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

default

✓ const ntlm = require('express-ntlm');

The module exports a single function. Use with Express middleware.

default

✓ import ntlm from 'express-ntlm';

✗ import ntlm from 'express-ntlm'; // use with ES module imports (if your project uses type: module)

ESM import works if package.json has 'type': 'module' or using .mjs.

ntlm (as middleware)

✓ app.use(ntlm({ domain: 'DOMAIN', domaincontroller: 'ldap://dc.example.com' }));

✗ app.use(ntlm); // missing options

The middleware requires an options object. At minimum, domain and domaincontroller are required for validation.

Sets up an Express server with NTLM authentication middleware, requiring LDAP domain controller.

const express = require('express'); const ntlm = require('express-ntlm'); const app = express(); // NTLM authentication middleware app.use(ntlm({ debug: (...args) => console.log(...args), domain: 'MYDOMAIN', domaincontroller: 'ldap://myad.example', })); app.all('*', (req, res) => { res.end(JSON.stringify(req.ntlm)); }); app.listen(3000, () => console.log('Server running on port 3000'));

Debug

Known issues

breakingUpgrading from v1.0: The fields for username, domain and workstation have different names: `UserName`, `DomainName`, `Workstation`.

fix

Update property names in your code from req.ntlm.username to req.ntlm.UserName, etc.

affects: >=1.0.0 <2.0.0

gotchaNTLM authenticates the TCP connection, not HTTP session. Behind a reverse proxy, multiple users may share the same connection, causing user mixup.

fix

Use connection-pinning (e.g., nginx ip_hash) or custom reverse proxy with session sharing.

affects: >=1.0.0

gotchaWithout validation (no domaincontroller), the middleware will accept any NTLM response, including fake ones. Security risk.

fix

Always provide a domaincontroller for LDAP validation in production.

affects: >=1.0.0

deprecatedOld method for NTLM without proxy (NTLM_No_Proxy) is deprecated; use the standard options.

fix

Use the standard middleware options; NTLM_No_Proxy is removed.

affects: >=2.5.0

Errors

Common errors & fixes

TypeError: Cannot read property 'authenticate' of null

The module could not extract NTLM type 2 or type 3 messages; often due to malformed NTLM headers.

fix

Ensure the client sends proper NTLM authentication; verify network setup and proxy configuration.

Error: connect ECONNREFUSED <ldap-server>:389

LDAP connection refused; domaincontroller host/port unreachable.

fix

Check LDAP server availability, firewall rules, and domaincontroller URL.

Error: NTLM type 2 message generation failed

The module failed to create an NTLM type 2 challenge.

fix

Update to latest version (2.6.1+); if persists, check client NTLM version support.

Upgrade

Version history

2.7.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

20 hits · last 30 days

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Resources

githubhttps://github.com/einfallstoll/express-ntlm ↗

packagehttps://www.npmjs.com/package/express-ntlm ↗