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Created August 30, 2017 19:15
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Basic HTTP Authentication for CloudFront with Lambda@Edge
'use strict';
exports.handler = (event, context, callback) => {
// Get request and request headers
const request = event.Records[0].cf.request;
const headers = request.headers;
// Configure authentication
const authUser = 'user';
const authPass = 'pass';
// Construct the Basic Auth string
const authString = 'Basic ' + new Buffer(authUser + ':' + authPass).toString('base64');
// Require Basic authentication
if (typeof headers.authorization == 'undefined' || headers.authorization[0].value != authString) {
const body = 'Unauthorized';
const response = {
status: '401',
statusDescription: 'Unauthorized',
body: body,
headers: {
'www-authenticate': [{key: 'WWW-Authenticate', value:'Basic'}]
callback(null, response);
// Continue request processing if authentication passed
callback(null, request);
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Habbie commented Dec 15, 2020

Line 23 is broken - the realm parameter is mandatory! This is documented in RFC7617 section 2 and I found out because Python's urllib's AuthHandler classes do not recognise the header without realm=.

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This is now also possible, cheaper and faster with the newly launched CloudFront Functions (

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@rkz - make sure that your trigger CloudFront Event is Viewer Request and not Origin Request. The auth headers are stripped out of Origin.

I added the 'Authorization' header to the cache key and it now comes through to the 'Origin Request'. My issue is that I need both this header as well as the origin domain for my lambda, and I can't determine the domain from the 'Viewer Request' . Wish this stuff was documented better.

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maheshglm commented Aug 22, 2022

Can we pick the credentials from secret manager? can anyone help with the code?

Tried adding aws-cdk to lamda@edge function that is attached to viewer request but size limitation of 1MB for Viewer Request is blocking me. Because with the inclusion of aws-cdk package, the zip file size is increasing more than 4 MB (even with ssm package). Any other workaround for this problem ??

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AlexBorsody commented Nov 25, 2022

It looks like Amazon has no official documentation on how to do this, Authorizers are only documented to use token auth with APIs, not basic auth.

What is a better alternative to securing a dev or staging site from prying eyes such as Firewall with IP restrictions can be unreliable with changing IPs and hinder developer productivity?

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