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Path Traversal in @backstage/plugin-scaffolder-backend

High severity GitHub Reviewed Published Nov 28, 2021 in backstage/backstage • Updated Feb 1, 2023

Package

npm @backstage/plugin-scaffolder-backend (npm)

Affected versions

< 0.15.14

Patched versions

0.15.14

Description

Impact

A malicious actor with write access to a registered scaffolder template is able to manipulate the template in a way that writes files to arbitrary paths on the scaffolder-backend host instance.

This vulnerability can in some situation also be exploited through user input when executing a template, meaning you do not need write access to the templates. This method will not allow the attacker to control the contents of the injected file however, unless the template is also crafted in a specific way that gives control of the file contents.

Patches

This vulnerability is fixed in version 0.15.14 of the @backstage/plugin-scaffolder-backend.

Workarounds

This attack is mitigated by restricting access and requiring reviews when registering or modifying scaffolder templates.

For more information

If you have any questions or comments about this advisory:

References

@Rugvip Rugvip published to backstage/backstage Nov 28, 2021
Published by the National Vulnerability Database Nov 29, 2021
Reviewed Nov 29, 2021
Published to the GitHub Advisory Database Dec 1, 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
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
High
Availability
Low

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:L/UI:N/S:C/C:N/I:H/A:L

EPSS score

0.075%
(35th percentile)

Weaknesses

CVE ID

CVE-2021-43783

GHSA ID

GHSA-mg3m-f475-28hv

Source code

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