From 07ec8062e605ba4e9bd153e1d264b02ac4ab8a0f Mon Sep 17 00:00:00 2001 From: Genadi Samokovarov Date: Thu, 14 Jun 2018 11:09:00 +0300 Subject: Introduce a guard against DNS rebinding attacks The ActionDispatch::HostAuthorization is a new middleware that prevent against DNS rebinding and other Host header attacks. By default it is included only in the development environment with the following configuration: Rails.application.config.hosts = [ IPAddr.new("0.0.0.0/0"), # All IPv4 addresses. IPAddr.new("::/0"), # All IPv6 addresses. "localhost" # The localhost reserved domain. ] In other environments, `Rails.application.config.hosts` is empty and no Host header checks will be done. If you want to guard against header attacks on production, you have to manually permit the allowed hosts with: Rails.application.config.hosts << "product.com" The host of a request is checked against the hosts entries with the case operator (#===), which lets hosts support entries of type RegExp, Proc and IPAddr to name a few. Here is an example with a regexp. # Allow requests from subdomains like `www.product.com` and # `beta1.product.com`. Rails.application.config.hosts << /.*\.product\.com/ A special case is supported that allows you to permit all sub-domains: # Allow requests from subdomains like `www.product.com` and # `beta1.product.com`. Rails.application.config.hosts << ".product.com" --- railties/CHANGELOG.md | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'railties/CHANGELOG.md') diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md index ff6a00f82b..59024b13ef 100644 --- a/railties/CHANGELOG.md +++ b/railties/CHANGELOG.md @@ -1,3 +1,38 @@ +* Introduce guard against DNS rebinding attacks + + The `ActionDispatch::HostAuthorization` is a new middleware that prevent + against DNS rebinding and other `Host` header attacks. It is included in + the development environment by default with the following configuration: + + Rails.application.config.hosts = [ + IPAddr.new("0.0.0.0/0"), # All IPv4 addresses. + IPAddr.new("::/0"), # All IPv6 addresses. + "localhost" # The localhost reserved domain. + ] + + In other environments `Rails.application.config.hosts` is empty and no + `Host` header checks will be done. If you want to guard against header + attacks on production, you have to manually whitelist the allowed hosts + with: + + Rails.application.config.hosts << "product.com" + + The host of a request is checked against the `hosts` entries with the case + operator (`#===`), which lets `hosts` support entries of type `RegExp`, + `Proc` and `IPAddr` to name a few. Here is an example with a regexp. + + # Allow requests from subdomains like `www.product.com` and + # `beta1.product.com`. + Rails.application.config.hosts << /.*\.product\.com/ + + A special case is supported that allows you to whitelist all sub-domains: + + # Allow requests from subdomains like `www.product.com` and + # `beta1.product.com`. + Rails.application.config.hosts << ".product.com" + + *Genadi Samokovarov* + * Remove redundant suffixes on generated helpers. *Gannon McGibbon* -- cgit v1.2.3