How java framework prevents cross-site scripting attacks

The Java framework prevents cross-site scripting inclusion attacks (XSSI) through the following strategies: Input validation: Use regular expressions or whitelists to validate user input and block malicious scripts. Output escaping: Escape user input using HTML entities or escape characters before outputting it, preventing the browser from interpreting it as code. HTTP header settings: Set HTTP headers such as X-XSS-Protection and Content-Security-Policy to enhance security.

How Java framework prevents cross-site scripting inclusion attacks (XSSi)

Preface

Cross-site scripting inclusion attacks (XSSI) are a serious cybersecurity threat that allow attackers to execute arbitrary JavaScript code in the victim's web browser. Java frameworks can prevent XSSi attacks through the following strategies:

Input Validation

By using regular expressions or whitelists to validate user input, malicious scripts can be effectively blocked . For example:

String input = request.getParameter("input");
if (!input.matches("[a-zA-Z0-9]+")) {
    throw new IllegalArgumentException("Invalid input");
}

Output Escape

User input can be escaped using HTML entities or escape characters before it is output to the web page. This will prevent the browser from interpreting the input as code:

String escapedInput = HtmlUtils.htmlEscape(input);

HTTP Header Settings

The framework can set the following HTTP headers to enhance security:

• X-XSS-Protection: This header notifies the browser to perform additional checks on cross-site requests.
• Content-Security-Policy: This header specifies the resource sources that are allowed to be loaded.

Practical case

The following is an example of using the Spring MVC framework to prevent XSSi attacks:

Code:

@PostMapping("/submit")
public String submit(@RequestParam String input) {
    // 输入验证
    if (!input.matches("[a-zA-Z0-9]+")) {
        throw new IllegalArgumentException("Invalid input");
    }

    // 输出转义
    String escapedInput = HtmlUtils.htmlEscape(input);

    // 设置 HTTP 头
    HttpServletResponse response = request.getResponse();
    response.addHeader("X-XSS-Protection", "1; mode=block");
    response.addHeader("Content-Security-Policy", "default-src 'self'");

    // 将转义后的输入显示在页面上
    return "result.jsp?input=" + escapedInput;
}

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