CVE-2021-41194 : Exploit Details and Defense Strategies

FirstUseAuthenticator is a JupyterHub authenticator that helps new users set their password. A vulnerability in versions prior to 1.0.0 allows unauthorized access to any user's account.

Understanding CVE-2021-41194

FirstUseAuthenticator in JupyterHub has an improper access control vulnerability that can be exploited.

What is CVE-2021-41194?

The CVE-2021-41194 vulnerability in JupyterHub's FirstUseAuthenticator allows unauthorized access to user accounts in versions prior to 1.0.0, if

create_users=True

and the username is known or guessed.

The Impact of CVE-2021-41194

Base Score: 9.1 (Critical)
Attack Vector: Network
Confidentiality Impact: High
Integrity Impact: High
No privileges required for exploitation
No user interaction required
No availability impact
Scope: Unchanged

Technical Details of CVE-2021-41194

This section provides in-depth technical details regarding the vulnerability.

Vulnerability Description

The vulnerability allows unauthorized access to user accounts in JupyterHub versions below 1.0.0.

Affected Systems and Versions

Product: FirstUseAuthenticator
Vendor: JupyterHub
Versions Affected: < 1.0.0

Exploitation Mechanism

Unauthorized access can occur when

create_users=True

and the username is known or guessed.

Mitigation and Prevention

Steps to mitigate the vulnerability in CVE-2021-41194.

Immediate Steps to Take

Upgrade to version 1.0.0 or newer
Apply the available patch manually
Disable user creation with

c.FirstUseAuthenticator.create_users = False

Long-Term Security Practices

Regularly monitor for security advisories and updates
Educate users on secure password practices

Patching and Updates

Upgrade to version 1.0.0 or above to address the vulnerability