Java Development: How to Code Security and Vulnerability Protection-javaTutorial-php.cn

Java Development: How to Code Security and Vulnerability Protection

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Release： 2023-09-20 11:51:30

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Java Development: How to Code Security and Vulnerability Protection

Java Development: Code Security and Vulnerability Protection

Abstract:
In the current Internet era, code security and vulnerability protection are crucial to Java development. This article will introduce some common code security risks and vulnerabilities and provide corresponding solutions. At the same time, concrete code examples demonstrate how to prevent these security issues.

Password security
Passwords are common security risks and are vulnerable to attacks such as brute force cracking and credential stuffing. In order to ensure the security of passwords, here are a few suggestions:
(1) Use complex password algorithms: such as SHA-256, BCrypt, etc., and avoid using the one-way encryption algorithm MD5.
(2) Add salt to store passwords: Improve the security of password storage by adding a random string (salt) to the password and then encrypting it.
(3) Use verification code: When users log in and register, use verification code to protect user accounts from malicious attacks.

Sample code:

import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.RandomStringUtils;

public class PasswordUtils {
    private static final int SALT_LENGTH = 16;
    
    public static String encryptPassword(String password) {
        String salt = RandomStringUtils.randomAlphanumeric(SALT_LENGTH);
        String encryptedPassword = DigestUtils.sha256Hex(password + salt);
        return salt + encryptedPassword;
    }
    
    public static boolean checkPassword(String inputPassword, String storedPassword) {
        String salt = storedPassword.substring(0, SALT_LENGTH);
        String encryptedInputPassword = DigestUtils.sha256Hex(inputPassword + salt);
        return storedPassword.equals(salt + encryptedInputPassword);
    }
}

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SQL injection attack
SQL injection attack refers to destroying the security of the database by users entering malicious SQL code. Here are several ways to avoid SQL injection attacks:
(1) Never splice SQL statements directly, but use parameterized queries or prepared statements.
(2) Input verification and filtering: Verify, filter and escape user input to ensure that there is no malicious code in user input.

Sample code:

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DatabaseUtils {
    public static void main(String[] args) {
        String username = "admin'; DROP TABLE users; --";
        String password = "pass123";

        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try {
            conn = getConnection();
            String sql = "SELECT * FROM users WHERE username = ? AND password = ?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, username);
            pstmt.setString(2, password);
            
            rs = pstmt.executeQuery();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeResources(conn, pstmt, rs);
        }
    }

    private static Connection getConnection() throws SQLException {
        // 获取数据库连接
        return null;
    }

    private static void closeResources(Connection conn, PreparedStatement pstmt, ResultSet rs) {
        // 关闭数据库连接和其他资源
    }
}

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Cross-site scripting attack (XSS)
XSS attack means that the attacker obtains users by injecting malicious script code on the website of sensitive information. The following are several methods to prevent XSS attacks:
(1) Validate and filter user input, especially escaping special characters.
(2) When outputting data to the page, use appropriate encoding methods for processing.

Sample code:

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>XSS Prevention</title>
</head>
<body>
    <h1>Welcome <%= StringEscapeUtils.escapeHtml4(request.getParameter("name")) %></h1>
</body>
</html>

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File upload vulnerability
The file upload vulnerability means that an attacker can execute remote commands by uploading a file containing malicious code. The following are several methods to prevent file upload vulnerabilities:
(1) Strictly limit the type and size of uploaded files.
(2) Use random file names and secure storage paths.

Sample code:

import java.io.File;
import java.io.IOException;
import java.util.UUID;

public class FileUploadUtils {
    public static void main(String[] args) {
        String fileName = "evil_script.jsp";
        File file = new File("/uploads/" + UUID.randomUUID().toString() + ".jpg");

        try {
            file.createNewFile();
            // 处理上传文件的逻辑
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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Conclusion:
Code security and vulnerability protection are crucial to Java development. This article introduces solutions to password security, SQL injection attacks, cross-site scripting attacks, and file upload vulnerabilities, and provides corresponding code examples. Developers should always be vigilant and take appropriate security measures to prevent code security issues and vulnerabilities.

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