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Creation of Temporary File in Directory with Insecure Permissions in auto-generated Java, Scala code

Moderate severity GitHub Reviewed Published May 10, 2021 in OpenAPITools/openapi-generator • Updated Jan 29, 2023

Package

maven org.openapitools:openapi-generator (Maven)

Affected versions

< 5.1.0

Patched versions

5.1.0

Description

Impact

This vulnerability impacts generated code. If this code was generated as a one-off occasion, not as a part of an automated CI/CD process, this code will remain vulnerable until fixed manually!

On Unix-Like systems, the system temporary directory is shared between all local users. When files/directories are created, the default umask settings for the process are respected. As a result, by default, most processes/apis will create files/directories with the permissions -rw-r--r-- and drwxr-xr-x respectively, unless an API that explicitly sets safe file permissions is used.

This vulnerability exists due to the use of the JDK method File.createTempFile. This method creates an insecure temporary files that can leave application and system data vulnerable to exposure.

Auto-generated code (Java, Scala) that deals with uploading or downloading binary data through API endpoints will create insecure temporary files during the process. For example, if the API endpoint returns a PDF file, the auto-generated clients will first download the PDF into a insecure temporary file that can be read by anyone on the system.

Affected generators:

Patches

The issue has been patched by changing the generated code to use the JDK method Files.createTempFile and released in the v5.1.0 stable version.

This vulnerability has the same root cause as CVE-2021-21364 from the swagger-api/swagger-codegen project as this project and that one both share the same original source tree.
GHSA-hpv8-9rq5-hq7w

For more information

If you have any questions or comments about this advisory:

References

@wing328 wing328 published to OpenAPITools/openapi-generator May 10, 2021
Reviewed May 10, 2021
Published by the National Vulnerability Database May 10, 2021
Published to the GitHub Advisory Database May 11, 2021
Last updated Jan 29, 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
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
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:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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.
(21st percentile)

Weaknesses

Improper Privilege Management

The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Learn more on MITRE.

Insecure Temporary File

Creating and using insecure temporary files can leave application and system data vulnerable to attack. Learn more on MITRE.

Creation of Temporary File With Insecure Permissions

Opening temporary files without appropriate measures or controls can leave the file, its contents and any function that it impacts vulnerable to attack. Learn more on MITRE.

Creation of Temporary File in Directory with Insecure Permissions

The product creates a temporary file in a directory whose permissions allow unintended actors to determine the file's existence or otherwise access that file. Learn more on MITRE.

Exposure of Resource to Wrong Sphere

The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource. Learn more on MITRE.

CVE ID

CVE-2021-21430

GHSA ID

GHSA-cqxr-xf2w-943w

Source code

Credits

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