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DOS and Open Redirect with user input

High severity GitHub Reviewed Published Oct 11, 2021 in fastify/fastify-static • Updated Feb 1, 2023

Package

npm fastify-static (npm)

Affected versions

>= 4.2.4, < 4.4.1

Patched versions

4.4.1

Description

Impact

A redirect vulnerability in the fastify-static module allows remote attackers to redirect Mozilla Firefox users to arbitrary websites via a double slash // followed by a domain: http://localhost:3000//a//youtube.com/%2e%2e%2f%2e%2e.

A DOS vulnerability is possible if the URL contains invalid characters curl --path-as-is "http://localhost:3000//^/.."

The issue shows up on all the fastify-static applications that set redirect: true option. By default, it is false.

Patches

The issue has been patched in [email protected]

Workarounds

If updating is not an option, you can sanitize the input URLs using the rewriteUrl server option.

References

For more information

If you have any questions or comments about this advisory:

References

@mcollina mcollina published to fastify/fastify-static Oct 11, 2021
Reviewed Oct 11, 2021
Published to the GitHub Advisory Database Oct 12, 2021
Published by the National Vulnerability Database Oct 14, 2021
Last updated Feb 1, 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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
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:R/S:C/C:L/I:L/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(58th percentile)

Weaknesses

Uncaught Exception

An exception is thrown from a function, but it is not caught. Learn more on MITRE.

URL Redirection to Untrusted Site ('Open Redirect')

A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. Learn more on MITRE.

CVE ID

CVE-2021-22964

GHSA ID

GHSA-pgh6-m65r-2rhq

Source code

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