CVE-2021-41868 : Security Advisory and Response

OnionShare 2.3 before 2.4 allows remote unauthenticated attackers to upload files on a non-public node when using the --receive functionality.

Understanding CVE-2021-41868

OnionShare 2.3 before 2.4 is vulnerable to remote unauthenticated file upload attacks.

What is CVE-2021-41868?

CVE-2021-41868 is a vulnerability in OnionShare version 2.3 before 2.4 that enables remote unauthenticated attackers to upload files on a non-public node through the --receive feature.

The Impact of CVE-2021-41868

This vulnerability can lead to unauthorized file uploads on a non-public node, potentially compromising sensitive data and system integrity.

Technical Details of CVE-2021-41868

OnionShare 2.3 before 2.4 has the following technical details:

Vulnerability Description

The vulnerability allows remote unauthenticated attackers to upload files through the --receive functionality in OnionShare 2.3 before 2.4.

Affected Systems and Versions

Affected Versions: OnionShare 2.3 before 2.4
Affected Systems: Any system running OnionShare 2.3 before 2.4

Exploitation Mechanism

The exploit occurs when remote unauthenticated attackers utilize the --receive functionality to upload files on a non-public node in OnionShare 2.3 before 2.4.

Mitigation and Prevention

To address CVE-2021-41868, consider the following steps:

Immediate Steps to Take

Update OnionShare to version 2.4 or later.
Disable the --receive functionality if not required.
Monitor file uploads closely for any suspicious activity.

Long-Term Security Practices

Conduct regular security assessments and audits of the application.
Educate users on secure file sharing practices and potential risks.

Patching and Updates

Apply patches and updates timely to ensure the security of OnionShare.