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githubGitHub Advisory DatabaseGHSA-23X4-M842-FMWF
HistoryMay 11, 2021 - 12:04 a.m.

Creation of Temporary File in Directory with Insecure Permissions in the OpenAPI-Generator online generator

2021-05-1100:04:40
CWE-269
CWE-377
CWE-378
CWE-379
CWE-668
GitHub Advisory Database
github.com
49

CVSS2

4.4

Attack Vector

LOCAL

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:L/AC:M/Au:N/C:P/I:P/A:P

CVSS3

9.3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS

0.001

Percentile

17.8%

Impact

On Unix like systems, the system’s temporary directory is shared between all users on that system. A collocated user can observe the process of creating a temporary sub directory in the shared temporary directory and race to complete the creation of the temporary subdirectory.

This vulnerability is local privilege escalation because the contents of the outputFolder can be appended to by an attacker. As such, code written to this directory, when executed can be attacker controlled.

openapi-generator-online creates insecure temporary folders with File.createTempFile during the code generation process. The insecure temporary folders store the auto-generated files which can be read and appended to by any users on the system.

Vulnerable Code

https://github.com/OpenAPITools/openapi-generator/blob/c6530519975341d7784a252132b2f0854f488901/modules/openapi-generator-online/src/main/java/org/openapitools/codegen/online/service/Generator.java#L184-L187

This vulnerability exists due to a race condition between the deletion of the randomly generated temporary file and the creation of the temporary directory.

File outputFolder = File.createTempFile("codegen-", "-tmp"); // Attacker knows the full path of the file that will be generated
// delete the file that was created
outputFolder.delete(); // Attacker sees file is deleted and begins a race to create their own directory before the code generator
// and make a directory of the same name
// SECURITY VULNERABILITY: Race Condition! - Attacker beats the code generator and now owns this directory
outputFolder.mkdir();

Patches

The issue has been patched by changing the underlying logic to use Files.createTempFile and has been released in the v5.1.0 stable version.

This vulnerability has the same root cause as CVE-2021-21363 from the swagger-api/swagger-codegen project as this project and that one both share the same original source tree.
See: https://github.com/swagger-api/swagger-codegen/security/advisories/GHSA-pc22-3g76-gm6j

For more information

If you have any questions or comments about this advisory:

Affected configurations

Vulners
Node
org.openapitools\openapiMatchgenerator

CVSS2

4.4

Attack Vector

LOCAL

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:L/AC:M/Au:N/C:P/I:P/A:P

CVSS3

9.3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS

0.001

Percentile

17.8%

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