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ReDos vulnerability on guest checkout email validation

High severity GitHub Reviewed Published Dec 7, 2021 in solidusio/solidus • Updated May 4, 2023

Package

bundler solidus_core (RubyGems)

Affected versions

< 2.11.13
>= 3.0.0, < 3.0.4
>= 3.1.0, < 3.1.4

Patched versions

2.11.13
3.0.4
3.1.4

Description

Impact

Denial of service vulnerability that could be exploited during a guest checkout. The regular expression used to validate a guest order's email was subject to exponential backtracking through a fragment like a.a..

Before the patch, it can be reproduced in the console like this:

irb(main)> Spree::EmailValidator::EMAIL_REGEXP.match "[email protected].@"
processing time: 54.293660s
=> nil

To reproduce in the browser, fill in the "Customer Email" field with that fake email address during a guest checkout. Before that, you should open the browser dev tools and change the type attribute for that field from email to text. After entering a fake address and pressing the "Save & Continue" button, the browser will take a long term to perform the request before showing an error message for the invalid address. Eventually, making the email string even longer could lead to the exhaustion of server resources.

Patches

Versions 3.1.4, 3.0.4, and 2.11.13 have been patched to use a different regular expression.

There's an improbable chance that some orders in your system end up having associated an email address that is no longer valid. We've added a task to check precisely that:

bin/rails solidus:check_orders_with_invalid_email

The above will print information for every affected order if any.

Workarounds

If a prompt upgrade is not an option, please, add the following to config/application.rb:

config.after_initialize do
  Spree::EmailValidator.send(:remove_const, :EMAIL_REGEXP)
  Spree::EmailValidator::EMAIL_REGEXP = URI::MailTo::EMAIL_REGEXP
end

References

For more information

If you have any questions or comments about this advisory:

References

@waiting-for-dev waiting-for-dev published to solidusio/solidus Dec 7, 2021
Published by the National Vulnerability Database Dec 7, 2021
Reviewed Dec 7, 2021
Published to the GitHub Advisory Database Dec 7, 2021
Last updated May 4, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.104%
(44th percentile)

Weaknesses

CVE ID

CVE-2021-43805

GHSA ID

GHSA-qxmr-qxh6-2cc9

Source code

Credits

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