How to use Lua to protect against web security vulnerabilities in Nginx-Nginx-php.cn

How to use Lua to protect against web security vulnerabilities in Nginx

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Release： 2023-06-10 16:33:11

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In today's network environment, web security vulnerabilities have become a threat to all websites and applications. They can lead to data breaches, user information exposure, malware installation, and other catastrophic consequences. Therefore, it is very important to prevent and guard against web security vulnerabilities in Internet applications. Nginx is an open source, high-performance web server that is widely used in various websites on the Internet. This article will introduce how to use Lua in Nginx to protect against web security vulnerabilities.

1. What is Lua

Lua is a lightweight, compact, efficient and scalable scripting language that is widely used in game development, embedded systems, Web development and other applications . It is a language developed based on C language, so it can be seamlessly integrated with C language.

2. Application of Lua in Nginx

Nginx supports Lua module. Using Lua, you can easily extend Nginx to implement your own functions. Through the Lua module, you can use Lua code directly in the Nginx configuration file. The whole process is very simple and efficient.

3. Use Lua to protect against Web security vulnerabilities

Using Lua can easily prevent Web security vulnerabilities. Here is an introduction to using Lua to prevent two common Web security vulnerabilities, SQL injection vulnerabilities and XSS vulnerabilities.

SQL injection

The conventional anti-injection operation is to use SQL pre-compiled parameters to ensure that the input parameters are processed. The mysql module in Lua supports precompiled queries, and it processes the input of bind variables in a more intelligent way than conventional precompiled query operations, avoiding SQL injection vulnerabilities in conventional methods, and it is also very simple to use.

The following is a simple Lua application for secure access to the MySQL database:

-- 引入MySQL模块
local mysql = require "resty.mysql"

-- 初始化MySQL数据库连接池
local db = mysql:new()

-- 设定最大连接时间
db:set_timeout(1000)

-- 定义MySQL数据库的连接信息
local ip = "127.0.0.1"
local port = 3306
local database = "web_security"
local user = "root"
local password = "123456"

-- 连接MySQL数据库
local ok, err, errcode, sqlstate = db:connect({
    host = ip,
    port = port,
    database = database,
    user = user,
    password = password,
    charset = "utf8",
    max_packet_size = 1024 * 1024,
    ssl_verify = false,
})

-- 阻止SQL注入风险：' or '1'='1
local sql = "SELECT * FROM users WHERE username ='" .. ngx.quote_sql_str(username) .. "'"

-- 执行MySQL查询语句
local result, err, errcode, sqlstate = db:query(sql)

-- 关闭MySQL数据库连接池
db:set_keepalive(10000, 100)

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Use the ngx.quote_sql_str() function to escape the value in the username variable to ensure SQL query Not vulnerable to injection attacks.

XSS vulnerability

It is easy to prevent XSS attacks in Lua. You only need to introduce Lua code in the Nginx configuration file. For example, the following code can block JavaScript code in the HTML page:

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>防范XSS漏洞</title>
</head>
<body>

<div>
    <p>被阻止的XSS攻击</p>
    <script>alert("被阻止的XSS攻击");</script>
</div>

<div>
    <p>成功的XSS攻击</p>
    <script>alert("成功的XSS攻击");</script>
</div>

<% if ngx.var.block_xss then %>
<script>
    (function(){
        var nodes = document.querySelectorAll("script")
        for(var x = 0, length = nodes.length; x < length; x++ )
            nodes[x].parentNode.removeChild(nodes[x])
    })();
</script>
<% end %>

</body>
</html>

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In this example, when the block_xss variable in the configuration file is true, the HTML page will block all JavaScript in the browser through Lua script Script removal to avoid XSS attacks.

4. Summary

In this article, we introduced how to use Lua in Nginx to prevent web security vulnerabilities. In practical applications, we can use Lua modules to deal with various types of web security vulnerabilities, thereby ensuring the security and stability of our applications. The combination of Nginx and Lua has great potential in web application security. I hope this article can help you solve the problem of web security vulnerabilities.

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