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Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTJycXctdjI2NS1qZjhj

Open Redirect in ActionPack

Overview

There is a possible open redirect vulnerability in the Host Authorization middleware in Action Pack. This vulnerability has been assigned the CVE identifier CVE-2021-22942.

Versions Affected: >= 6.0.0.
Not affected: < 6.0.0
Fixed Versions: 6.1.4.1, 6.0.4.1

Impact

Specially crafted “X-Forwarded-Host” headers in combination with certain “allowed host” formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website.

Impacted applications will have allowed hosts with a leading dot. For example, configuration files that look like this:

config.hosts <<  '.EXAMPLE.com'

When an allowed host contains a leading dot, a specially crafted Host header can be used to redirect to a malicious website.

This vulnerability is similar to CVE-2021-22881, but CVE-2021-22881 did not take in to account domain name case sensitivity.

Releases

The fixed releases are available at the normal locations.

Workarounds

In the case a patch can’t be applied, the following monkey patch can be used in an initializer:

module ActionDispatch
  class HostAuthorization
    HOSTNAME = /[a-z0-9.-]+|\[[a-f0-9]*:[a-f0-9.:]+\]/i
    VALID_ORIGIN_HOST = /\A(#{HOSTNAME})(?::\d+)?\z/
    VALID_FORWARDED_HOST = /(?:\A|,[ ]?)(#{HOSTNAME})(?::\d+)?\z/

    private
      def authorized?(request)
        origin_host =
          request.get_header("HTTP_HOST")&.slice(VALID_ORIGIN_HOST, 1) || ""
        forwarded_host =
          request.x_forwarded_host&.slice(VALID_FORWARDED_HOST, 1) || ""
        @permissions.allows?(origin_host) &&
          (forwarded_host.blank? || @permissions.allows?(forwarded_host))
      end
  end
end
Permalink: https://github.com/advisories/GHSA-2rqw-v265-jf8c
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTJycXctdjI2NS1qZjhj
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: over 2 years ago
Updated: about 2 months ago


CVSS Score: 6.1
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Identifiers: GHSA-2rqw-v265-jf8c, CVE-2021-22942
References:

Affected Packages

rubygems:actionpack
Dependent packages: 1,669
Dependent repositories: 876,080
Downloads: 523,283,713 total
Affected Version Ranges: >= 6.1.0, <= 6.1.4, >= 6.0.0, <= 6.0.4
Fixed in: 6.1.4.1, 6.0.4.1
All affected versions: 6.0.0, 6.0.1, 6.0.2, 6.0.3, 6.0.4, 6.1.0, 6.1.1, 6.1.2, 6.1.3, 6.1.4
All unaffected versions: 0.9.0, 0.9.5, 1.0.0, 1.0.1, 1.1.0, 1.2.0, 1.3.0, 1.3.1, 1.4.0, 1.5.0, 1.5.1, 1.6.0, 1.7.0, 1.8.0, 1.8.1, 1.9.0, 1.9.1, 1.10.1, 1.10.2, 1.11.0, 1.11.1, 1.11.2, 1.12.0, 1.12.1, 1.12.2, 1.12.3, 1.12.4, 1.12.5, 1.13.0, 1.13.1, 1.13.2, 1.13.3, 1.13.4, 1.13.5, 1.13.6, 2.0.0, 2.0.1, 2.0.2, 2.0.4, 2.0.5, 2.1.0, 2.1.1, 2.1.2, 2.2.2, 2.2.3, 2.3.2, 2.3.3, 2.3.4, 2.3.5, 2.3.6, 2.3.7, 2.3.8, 2.3.9, 2.3.10, 2.3.11, 2.3.12, 2.3.14, 2.3.15, 2.3.16, 2.3.17, 2.3.18, 3.0.0, 3.0.1, 3.0.2, 3.0.3, 3.0.4, 3.0.5, 3.0.6, 3.0.7, 3.0.8, 3.0.9, 3.0.10, 3.0.11, 3.0.12, 3.0.13, 3.0.14, 3.0.15, 3.0.16, 3.0.17, 3.0.18, 3.0.19, 3.0.20, 3.1.0, 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.1.6, 3.1.7, 3.1.8, 3.1.9, 3.1.10, 3.1.11, 3.1.12, 3.2.0, 3.2.1, 3.2.2, 3.2.3, 3.2.4, 3.2.5, 3.2.6, 3.2.7, 3.2.8, 3.2.9, 3.2.10, 3.2.11, 3.2.12, 3.2.13, 3.2.14, 3.2.15, 3.2.16, 3.2.17, 3.2.18, 3.2.19, 3.2.20, 3.2.21, 3.2.22, 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.0.4, 4.0.5, 4.0.6, 4.0.7, 4.0.8, 4.0.9, 4.0.10, 4.0.11, 4.0.12, 4.0.13, 4.1.0, 4.1.1, 4.1.2, 4.1.3, 4.1.4, 4.1.5, 4.1.6, 4.1.7, 4.1.8, 4.1.9, 4.1.10, 4.1.11, 4.1.12, 4.1.13, 4.1.14, 4.1.15, 4.1.16, 4.2.0, 4.2.1, 4.2.2, 4.2.3, 4.2.4, 4.2.5, 4.2.6, 4.2.7, 4.2.8, 4.2.9, 4.2.10, 4.2.11, 5.0.0, 5.0.1, 5.0.2, 5.0.3, 5.0.4, 5.0.5, 5.0.6, 5.0.7, 5.1.0, 5.1.1, 5.1.2, 5.1.3, 5.1.4, 5.1.5, 5.1.6, 5.1.7, 5.2.0, 5.2.1, 5.2.2, 5.2.3, 5.2.4, 5.2.5, 5.2.6, 5.2.7, 5.2.8, 6.0.5, 6.0.6, 6.1.5, 6.1.6, 6.1.7, 7.0.0, 7.0.1, 7.0.2, 7.0.3, 7.0.4, 7.0.5, 7.0.6, 7.0.7, 7.0.8, 7.1.0, 7.1.1, 7.1.2, 7.1.3