PsiTransfer is an open source, self-hosted file sharing solution. Prior to version 2.2.0, the absence of restrictions on the endpoint, which allows users to create a path for uploading a file in a file distribution, allows an attacker to add arbitrary files to the distribution. The vulnerability allows an attacker to influence those users who come to the file distribution after them and slip the victim files with a malicious or phishing signature. Version 2.2.0 contains a patch for the issue.

CVE-2024-31453 allows users to violate the integrity of a file bucket and upload new files there, while the vulnerability with the number CVE-2024-31454 allows users to violate the integrity of a single file that is uploaded by another user by writing data there and not allows you to upload new files to the bucket. Thus, vulnerabilities are reproduced differently, require different security recommendations and affect different objects of the application’s business logic.

Affected: npm: psitransfer

**Summary** The absence of restrictions on the endpoint, which allows you to create a path for uploading a file in a file distribution, allows an attacker to add arbitrary files to the distribution.

**Details** Vulnerable endpoint: POST /files

**PoC** 1. Create a file distribution. <img width="1434" alt="Снимок экрана 2024-03-17 в 21 27 30" src="https://github.com/psi-4ward/psitransfer/assets/163760990/4634a6f7-6e7d-486e-9929-76156aaa1340">

2. Go to the link address (id of the file distribution is needed by an attacker to upload files there). <img width="1426" alt="Снимок экрана 2024-03-17 в 21 27 35" src="https://github.com/psi-4ward/psitransfer/assets/163760990/a57c910c-69e2-4b07-985d-b0a46c69891a">

3. Send a POST /files. As the value of the Upload-Metadata header we specify the sid parameter with the id of the file distribution obtained in the second step. In the response from the server in the Location header we get the path for uploading a new file to the file distribution. <img width="1403" alt="Снимок экрана 2024-03-17 в 21 28 09" src="https://github.com/psi-4ward/psitransfer/assets/163760990/8b839fb8-2c0b-432f-8503-e4c42a840056">

5. Send a PATCH /files/{{id}} request with arbitrary content in the request body. Id is taken from the previous step. <img width="1067" alt="Снимок экрана 2024-03-17 в 21 28 51" src="https://github.com/psi-4ward/psitransfer/assets/163760990/c5b2acf3-fdf1-4780-8c63-61a7f19338df">

Result: <img width="1432" alt="Снимок экрана 2024-03-17 в…