CVE-2022-39020: Uncovering Multiple Instances of XSS Vulnerabilities in Popular Educational Application

Cross-site scripting (XSS) vulnerabilities remain one of the most notorious cybersecurity risks facing web applications today. In this post, we will dive deep into the critical XSS vulnerabilities we discovered in a popular educational application (CVE-2022-39020). We'll break down the vulnerable features, provide code snippets showcasing the issues, and demonstrate potential exploits. Additionally, we will provide links to the original references and report, offering further insights into the matter.

Vulnerable Features

Our team identified multiple instances of XSS vulnerabilities, both stored and reflected, in the application. Specifically, the affected features include:

File upload

3. News

Calendar event creation

These vulnerabilities expose users and administrators to potential cyber-attacks like session hijacking, account takeover, and sensitive data theft.

Student Assessment Submission

In the student assessment submission feature, the application fails to sanitize user input before rendering it in the DOM. Here is a simplified version of the vulnerable code snippet:

function displayAssessment(text) {
    var assessmentArea = document.getElementById("assessment");
    assessmentArea.innerHTML = text;
}

var userInput = document.getElementById("input").value;
displayAssessment(userInput);

An attacker can craft malicious input, such as <script>alert('XSS')</script>, which would execute when rendered in the DOM.

File Upload

In the file upload feature, the application does not validate the uploaded file's name and displays it without sanitization. A vulnerable code snippet is as follows:

function displayFileName(fileName) {
    var fileUploadArea = document.getElementById("file-upload");
    fileUploadArea.innerHTML = "Uploaded file: " + fileName;
}

var uploadedFile = document.getElementById("input-file").files[].name;
displayFileName(uploadedFile);

An attacker can upload a file with a malicious name, like test"><img src=x onerror=alert('XSS')>.pdf, which would trigger the XSS payload.

News

In the news feature, user-generated content, such as a news title, is not properly sanitized before being rendered. The following code snippet demonstrates this vulnerability:

function displayNewsTitle(title) {
    var newsTitleArea = document.getElementById("news-title");
    newsTitleArea.innerHTML = title;
}

var newsTitleInput = document.getElementById("input-title").value;
displayNewsTitle(newsTitleInput);

Using a malicious news title like <iframe src="javascript:alert('XSS');"></iframe>, the attacker can inject and execute an XSS payload.

ePortfolio

The ePortfolio feature also suffers from stored XSS vulnerabilities, as it fails to sanitize user input when storing and displaying the data. Here's an example of the vulnerable code snippet:

function displayPortfolio(portfolioText) {
    var portfolioArea = document.getElementById("portfolio");
    portfolioArea.innerHTML = portfolioText;
}

var userPortfolioInput = document.getElementById("input-portfolio").value;
displayPortfolio(userPortfolioInput);

An attacker can submit an ePortfolio entry with a malicious payload like <img src="x" onerror="alert('XSS')">.

Calendar Event Creation

The calendar event creation feature does not sanitize user-defined event descriptions before rendering them in the application. Consider the following vulnerable code:

function displayEventDescription(description) {
    var eventDescriptionArea = document.getElementById("event-description");
    eventDescriptionArea.innerHTML = description;
}

var eventDescriptionInput = document.getElementById("input-description").value;
displayEventDescription(eventDescriptionInput);

An attacker can exploit this vulnerability using a malicious input like <svg/onload=alert('XSS')> for the calendar event description.

Original References and Report

To learn more about these critical vulnerabilities and their potential impact, refer to the following resources:

1. CVE-2022-39020 Official Report
2. National Vulnerability Database (NVD) Entry for CVE-2022-39020
3. OWASP Cross-Site Scripting (XSS)

In conclusion, the multiple instances of XSS vulnerabilities we uncovered in the educational application (CVE-2022-39020) expose users and administrators to serious security risks. As a responsible cybersecurity community, we encourage developers to follow secure coding practices and businesses to always keep their applications up to date to mitigate such vulnerabilities.

Timeline

Published on: 10/31/2022 21:15:00 UTC
Last modified on: 11/01/2022 19:31:00 UTC