CVE-2021-32798 : Security Advisory and Response

The CVE-2021-32798, also known as Failure to Sanitize Special Elements into a Different Plane (Special Element Injection) in notebook, affects Jupyter notebook versions 5.7.11 and below, as well as versions from 6.0.0 to 6.4.1. This vulnerability allows untrusted notebooks to execute code when opened in Jupyter Notebook, leading to a critical impact.

Understanding CVE-2021-32798

This section will provide insights into the nature of CVE-2021-32798 and its implications.

What is CVE-2021-32798?

The Jupyter notebook, a web-based environment for interactive computing, contains a vulnerability that enables the execution of arbitrary code due to the deprecated Google Caja version used for user input sanitization. Opening a malicious ipynb document in Jupyter Notebook can trigger a Cross-Site Scripting (XSS) attack, allowing attackers to run code on victim computers through Jupyter APIs.

The Impact of CVE-2021-32798

With a CVSSv3.1 base score of 10, CVE-2021-32798 poses a critical threat with high confidentiality and integrity impacts. The attack complexity is low, and the vector is network-based, requiring no user interaction. The scope changes due to the injection of special elements into a different plane.

Technical Details of CVE-2021-32798

In this section, we will delve into the specific technical aspects of CVE-2021-32798.

Vulnerability Description

The vulnerability arises from the improper handling of input data, leading to the execution of code when loading untrusted notebooks in Jupyter Notebook.

Affected Systems and Versions

Jupyter notebook versions >= 6.0.0 and < 6.4.1, as well as versions < 5.7.11, are impacted by this vulnerability.

Exploitation Mechanism

By exploiting a public Caja bypass, attackers can inject malicious code through XSS in ipynb documents, enabling them to execute arbitrary commands on victim machines.

Mitigation and Prevention

To safeguard against CVE-2021-32798, immediate actions and long-term security practices are crucial.

Immediate Steps to Take

Users are advised to update their Jupyter notebook to a secure version that addresses the vulnerability. Additionally, exercise caution when opening untrusted ipynb files to prevent code execution.

Long-Term Security Practices

It is recommended to regularly update software, utilize security tools like content security policies, and educate users about the risks of opening files from unknown or untrusted sources.

Patching and Updates

Stay informed about security advisories and patches released by Jupyter to mitigate the risk of special element injection vulnerabilities.