利用HttpApplicaton请求管道防止SQL注入

Posted 2020-11-09 LoveTomato

HttpApplication通过事件管道的方式处理请求，注意对请求的数据过滤filter和根据请求的类型交由相应的处理程序Handler处理。
管道注入由两种一种实现接口IHttpModule,另一种直接Global类中添加方法。
SQL注入网站安全的威胁，关防止的方法：一种不允许敏感数据请求，一种将敏感数据重字符串中过滤。要求针对所有的用户请求，所有在BeginRequest事件中处理（也可以说是一种AOP编程）。

CODE

SQL注入处理类

public class SQLInjectionHelper
    {
        public static bool ValidUrlData(string request)
        {
            bool result = false;
            //获取pos数据
            if(request == "POST")
            {
                for(int i = 0; i < HttpContext.Current.Request.Form.Count; i++)
                {
                    result = ValidData(HttpContext.Current.Request.Form[i].ToString());
                    if (result)
                    {
                        break;
                    }
                }
            }
            //获取QueryString中的数据
            else
            {
                for(int i = 0; i < HttpContext.Current.Request.QueryString.Count; i++)
                {
                    result = ValidData(HttpContext.Current.Request.QueryString[i].ToString());
                    if (result)
                    {
                        break;
                    }
                }
            }

            return result;
        }

        /// <summary>
        /// 判断是否存在注入代码
        /// </summary>
        /// <param name="inputData"></param>
        /// <returns></returns>
        private static bool ValidData(string inputData)
        {
            if (Regex.IsMatch(inputData, GetRegexString())){
                return true;
            }
            else
            {
                return false;
            }
        }
        
        /// <summary>
        /// 获取正则表达式
        /// </summary>
        /// <returns></returns>
        private static string GetRegexString()
        {
            string[] strBadChar = { "and" ,"exec","insert","select","delete","update" ,"count",
                "from"," drop","asc"," char","or" ,"%",";",":","\‘","\"","-"," chr" ,"mid","master","truncate",
                "char","declare" ,"SiteName","net user","xp_ cmdshell","/add" ,"exec master. dbo. xp_ cmdshell",
                "net localgroup administrators" };
            string str_Regex = ".*(";
            for(int i = 0; i < strBadChar.Length-1; i++)
            {
                str_Regex += strBadChar[i] + "|";
            }
            str_Regex += strBadChar[strBadChar.Length - 1] + ").*";
            return str_Regex;
        }
    }

添加到Global类

        void Application_BeginRequest(object sender,EventArgs e)
        {
            bool result = false;
            result = SQLInjectionHelper.ValidUrlData(Request.RequestType.ToUpper());
            if (result)
            {
                Response.Write("您提交的数据有恶意字符");
                Response.End();
            }
        }