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StaticFile.fromUrl can leak presence of a directory

Moderate severity GitHub Reviewed Published May 27, 2021 in http4s/http4s • Updated Feb 1, 2023

Package

maven org.http4s:http4s-core (Maven)

Affected versions

>= 0.21.7, < 0.21.24
>= 0.22.0-M1, <= 0.22.0-M8
= 0.23.0-M1
>= 1.0.0-M1, <= 1.0.0-M22

Patched versions

0.21.24
0.22.0-RC1
0.23.0-RC1
1.0.0-M23

Description

Impact

StaticFile.fromUrl can leak the presence of a directory on a server when the URL scheme is not file://, and the URL points to a fetchable resource under its scheme and authority. The function returns F[None], indicating no resource, if url.getFile is a directory, without first checking the scheme or authority of the URL. If a URL connection to the scheme and URL would return a stream, and the path in the URL exists as a directory on the server, the presence of the directory on the server could be inferred from the 404 response. The contents and other metadata about the directory are not exposed.

This affects http4s versions:

  • 0.21.7 through 0.21.23
  • 0.22.0-M1 through 0.22.0-M8
  • 0.23.0-M1
  • 1.0.0-M1 through 1.0.0-M22

Patches

The patch is available in the following versions:

  • v0.21.24
  • v0.22.0-RC1
  • v0.23.0-RC1
  • v1.0.0-M23

Note: a previous version of this advisory incorrectly referred to 0.22.0-M9 and 0.23.0-M2.

Workarounds

Don't call StaticFile.fromUrl with non-file URLs.

For more information

If you have any questions or comments about this advisory:

References

@rossabaker rossabaker published to http4s/http4s May 27, 2021
Published by the National Vulnerability Database May 27, 2021
Reviewed May 27, 2021
Published to the GitHub Advisory Database May 28, 2021
Last updated Feb 1, 2023

Severity

Moderate

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
Changed
Confidentiality
Low
Integrity
None
Availability
None

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:C/C:L/I:N/A:N

EPSS score

0.095%
(42nd percentile)

Weaknesses

CVE ID

CVE-2021-32643

GHSA ID

GHSA-6h7w-fc84-x7p6

Source code

No known source code
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