通过HttpModule、httpHandlers防止SQL注入式攻击

1、通过HttpModule防止SQL注入式攻击，适用于.net1.1程序
（1）新建类文件SqlHttpModule.cs，具体代码类似如下：

SqlHttpModule.cs

using  System;
using  System.Data;
using  System.Configuration;
using  System.Web;
using  System.Web.Security;
using  System.Web.UI;
using  System.Web.UI.WebControls;
using  System.Web.UI.HtmlControls;
using  System.Text.RegularExpressions;

namespace  HttpModule.Class
{
     ///   <summary>
     ///  SqlInPost 的摘要说明
     ///   </summary>
     public   class  SqlHttpModule : System.Web.IHttpModule
    {
         public  SqlHttpModule()
        {
        }

         public   void  Dispose()
        {
        }

         public   void  Init(HttpApplication context)
        {
            context.AcquireRequestState  +=   new  EventHandler(context_AcquireRequestState);
        }

         private   void  context_AcquireRequestState( object  sender, EventArgs e)
        {
            HttpContext context  =  ((HttpApplication)sender).Context;            
             try
            {
                 string  getkeys  =   string .Empty;  
                 string  keyvalue  =   string .Empty;
                 string  strErrorAlertScript  =   " <script type=\"text/javascript\">alert('字符串格式非法，请重新输入！');history.go(-1);</script> " ;
                 string  requestUrl  =  context.Request.Path.ToString();
                 #region  URL提交数据
                 if  (context.Request.QueryString  !=   null )
                {
                     for  ( int  i  =   0 ; i  <  context.Request.QueryString.Count; i ++ )
                    {
                        getkeys  =  context.Request.QueryString.Keys[i];
                        keyvalue  =  context.Server.UrlDecode(context.Request.QueryString[getkeys]).Replace( " ' " ,  "" );

                         if  ( ! IsSafeString(keyvalue))
                        {
                            context.Response.Write(strErrorAlertScript);
                            context.Response.End();
                             break ;
                        }
                    }
                }
                 #endregion

                 #region  表单提交数据
                 if  (context.Request.Form  !=   null )
                {
                     for  ( int  i  =   0 ; i  <  context.Request.Form.Count; i ++ )
                    {
                        getkeys  =  context.Request.Form.Keys[i].ToUpper();
                         if  (getkeys  ==   " __VIEWSTATE "   ||  getkeys  ==   " __EVENTARGUMENT "   ||  getkeys  ==   " __EVENTTARGET "   ||  getkeys  ==   " __CLIENTPOSTDATA__ " )  continue ;

                        keyvalue  =  context.Server.HtmlDecode(context.Request.Form[i]).Replace( " ' " ,  "" );
                         if  ( ! IsSafeString(keyvalue))
                        {
                            context.Response.Write(strErrorAlertScript);
                            context.Response.End();
                             break ;
                        }
                    }
                }
                 #endregion
            }
             catch  (Exception ex)
            {
            }
        }

         // 判断是否为安全字符串
         public   bool  IsSafeString( string  strText)
        {
             bool  bResult  =   true ;
             // strText = Regex.Replace(strText, "[\\s]{1,}", "");     // two or more spaces
            strText  =  Regex.Replace(strText,  " (<[b|B][r|R]/*>)+|(<[p|P](.|\\n)*?>) " ,  " \n " );     // <br>


             string  FilterSql  =  System.Configuration.ConfigurationSettings.AppSettings[ " SqlHttpModule_KeyWord " ]; // 将关键词组配置在webconfig中
             if (FilterSql == null   ||  FilterSql == "" )
            {
                 string [] UnSafeArray  =   new   string [ 23 ];
                UnSafeArray[ 0 ]  =   " ' " ;
                UnSafeArray[ 1 ]  =   " xp_cmdshell  " ;
                UnSafeArray[ 2 ]  =   " declare " ;
                UnSafeArray[ 3 ]  =   " netlocalgroupadministrators  " ;
                UnSafeArray[ 4 ]  =   " delete  " ;
                UnSafeArray[ 5 ]  =   " truncate  " ;
                UnSafeArray[ 6 ]  =   " netuser  " ;
                UnSafeArray[ 7 ]  =   " /add  " ;
                UnSafeArray[ 8 ]  =   " drop  " ;
                UnSafeArray[ 9 ]  =   " update  " ;
                UnSafeArray[ 10 ]  =   " select  " ;
                UnSafeArray[ 11 ]  =   " union  " ;  
                UnSafeArray[ 12 ]  =   " exec  " ;
                UnSafeArray[ 13 ]  =   " create  " ;
                UnSafeArray[ 14 ]  =   " insertinto  " ;
                UnSafeArray[ 15 ]  =   " sp_  " ;
                UnSafeArray[ 16 ]  =   " exec  " ;
                UnSafeArray[ 17 ]  =   " create  " ;
                UnSafeArray[ 18 ]  =   " insert  " ;
                UnSafeArray[ 19 ]  =   " masterdbo  " ;
                UnSafeArray[ 20 ]  =   " sp_  " ;
                UnSafeArray[ 21 ]  =   " ;--  " ;
                UnSafeArray[ 22 ]  =   " 1=  " ;
                 foreach  ( string  strValue  in  UnSafeArray)
                {
                 
                     if  (strText.ToLower().IndexOf(strValue)  >   - 1 )
                    {
                        bResult  =   false ;
                         break ;
                    }
                }
            }
             else
            {
                 string  sqlStr  =  FilterSql;
                 string [] sqlStrs  =  sqlStr.Split( ' | ' );
                 foreach  ( string  ss  in  sqlStrs)
                {
                     if  (strText.ToLower().IndexOf(ss)  >=   0 )
                    {                        
                        bResult  =   false ;
                         break ;
                    }
                }            
            }
             return  bResult;
        }

    }
}

 
（2）在web.config文件中做以下配置
   </system.web>
     <httpModules>
           <add name="SqlHttpModule" type="HttpModule.Class.SqlHttpModule, HttpModule" />
     </httpModules>
   </system.web> 

 

2、通过httpHandlers防止SQL注入式攻击，适用于.net2.0及以上程序
（1）新建类文件SqlhttpHandlers.cs，具体代码类似如下：

SqlhttpHandlers.cs

using  System;
using  System.Data;
using  System.Configuration;
using  System.Web;
using  System.Web.Security;
using  System.Web.UI;
using  System.Web.UI.WebControls;
using  System.Web.UI.WebControls.WebParts;
using  System.Web.UI.HtmlControls;
using  System.Text.RegularExpressions;
using  System.Collections.Specialized;
namespace  httpHandlers
{
     ///   <summary>
     ///  SqlInPost 的摘要说明
     ///   </summary>
     public   class  SqlhttpHandlers : IHttpHandlerFactory
    {
         public  SqlhttpHandlers()
        {
             //
             //  TODO: 在此处添加构造函数逻辑
             //
        }


         public   virtual  IHttpHandler GetHandler(HttpContext context,  string  requestType,  string  url,  string  pathTranslated)
        {
             // 得到编译实例(通过反射)
            PageHandlerFactory factory  =  (PageHandlerFactory)Activator.CreateInstance( typeof (PageHandlerFactory),  true );
            IHttpHandler handler  =  factory.GetHandler(context, requestType, url, pathTranslated);
             // 过滤字符串
             if  (requestType  ==   " POST " )
            {
                Page page  =  handler  as  Page;
                 if  (page  !=   null )
                    page.PreLoad  +=   new  EventHandler(FormFilterStrFactoryHandler_PreLoad);
            }
             if  (requestType  ==   " GET " )
            {
                Page page  =  handler  as  Page;
                 if  (page  !=   null )
                    page.PreLoad  +=   new  EventHandler(RequestFilterStrFactoryRHandler_PreLoad);
            }
             // 返回
             return  handler;
        }



        public   virtual   void  ReleaseHandler(IHttpHandler handler)
        {

        }
         ///   <summary>
         ///  过滤TextBox、Input和Textarea中非法字符
         ///   </summary>
         ///   <param name="sender"></param>
         ///   <param name="e"></param>
        void  FormFilterStrFactoryHandler_PreLoad( object  sender, EventArgs e)
        {
             try
            {
                   bool  isSafe  =   true ;
                Page page  =  sender  as  Page;
                NameValueCollection postData  =  page.Request.Form;
                 foreach  ( string  postKey  in  postData)
                {
                    Control ctl  =  page.FindControl(postKey);
                     if  (ctl  as  TextBox  !=   null )
                    {
                       ((TextBox)ctl).Text  =  ((TextBox)ctl).Text.Replace( " ' " ,  " ＇ " );
                        string  strValue  =  ((TextBox)ctl).Text.Trim();
                        if  ( ! IsSafeString(strValue))
                       {
                          isSafe  =   false ;
                           break ;
                       }
                      
                         continue ;
                    }
                     if  (ctl  as  HtmlInputControl  !=   null )
                    {
       
                        ((HtmlInputControl)ctl).Value  =  ((HtmlInputControl)ctl).Value.Replace( " ' " ,  " ＇ " );
                          string  strValue  =  ((HtmlInputControl)ctl).Value.Trim();
                         if  ( ! IsSafeString(strValue))
                        {
                            isSafe  =   false ;
                             break ;
                        }
                         continue ;
                    }
                     if  (ctl  as  HtmlTextArea  !=   null )
                    {
                        ((HtmlTextArea)ctl).Value  =  ((HtmlTextArea)ctl).Value.Replace( " ' " ,  " ＇ " );
                         string  strValue  =  ((HtmlTextArea)ctl).Value.Trim();
                         if  ( ! IsSafeString(strValue))
                        {
                            isSafe  =   false ;
                             break ;
                        }        
                         continue ;
                   }                
                }
                 if  ( ! isSafe)
                {
                    page.Response.Write( " <b><font color='red' font-size=12pt>字符串格式非法!</font></b> " );
                    page.Response.End();
                }
            }
             catch (Exception ex)
            {
                 string  a  =  ex.Message;
            }
        }


         


         ///   <summary>
         ///  过滤QueryString 中的非法字符串
         ///   </summary>
         ///   <param name="sender"></param>
         ///   <param name="e"></param>
         protected   void  RequestFilterStrFactoryRHandler_PreLoad( object  sender, EventArgs e)
        {
             try
            {
                Page page  =  sender  as  Page;
                NameValueCollection QueryNV  =  page.Request.QueryString;
                 bool  isSafe  =   true ;
                 for  ( int  i  =   0 ; i  <  QueryNV.Count; i ++ )
                {
                     if  ( ! IsSafeString(QueryNV.Get(i)))
                    {
                        isSafe  =   false ;
                         break ;
                    }
                }
                 if  ( ! isSafe)
                {
                    page.Response.Write( " <b><font color='red' font-size=12pt>字符串格式非法!</font></b> " );
                    page.Response.End();
                }
            }
             catch  { }
        }





         // 判断是否为安全字符串
         public   bool  IsSafeString( string  strText)
        {
             bool  bResult  =   true ;
            strText  =  Regex.Replace(strText,  " [\\s]{1,} " ,  "" );     // two or more spaces
            strText  =  Regex.Replace(strText,  " (<[b|B][r|R]/*>)+|(<[p|P](.|\\n)*?>) " ,  " \n " );     // <br>

             string [] UnSafeArray  =   new   string [ 23 ];
            UnSafeArray[ 0 ]  =   " ' " ;
            UnSafeArray[ 1 ]  =   " xp_cmdshell " ;
            UnSafeArray[ 2 ]  =   " declare " ;
            UnSafeArray[ 3 ]  =   " netlocalgroupadministrators " ;
            UnSafeArray[ 4 ]  =   " delete " ;
            UnSafeArray[ 5 ]  =   " truncate " ;
            UnSafeArray[ 6 ]  =   " netuser " ;
            UnSafeArray[ 7 ]  =   " /add " ;
            UnSafeArray[ 8 ]  =   " drop " ;
            UnSafeArray[ 9 ]  =   " update " ;
            UnSafeArray[ 10 ]  =   " select " ;
            UnSafeArray[ 11 ]  =   " union " ;
            UnSafeArray[ 12 ]  =   " exec " ;
            UnSafeArray[ 13 ]  =   " create " ;
            UnSafeArray[ 14 ]  =   " insertinto " ;
            UnSafeArray[ 15 ]  =   " sp_ " ;
            UnSafeArray[ 16 ]  =   " exec " ;
            UnSafeArray[ 17 ]  =   " create " ;
            UnSafeArray[ 18 ]  =   " insertinto " ;
            UnSafeArray[ 19 ]  =   " masterdbo " ;
            UnSafeArray[ 20 ]  =   " sp_ " ;
            UnSafeArray[ 21 ]  =   " ;-- " ;
            UnSafeArray[ 22 ]  =   " 1= " ;
             foreach  ( string  strValue  in  UnSafeArray)
            {
                 
                 if  (strText.ToLower().IndexOf(strValue)  >   - 1 )
                {
                    bResult  =   false ;
                     break ;
                }
            }
             return  bResult;
        }

    }
}

 
 （2）在web.config文件中做以下配置
   </system.web>
     <httpHandlers>
        <add verb="*" path="*.aspx" type="httpHandlers.SqlhttpHandlers, httpHandlers"/>
     </httpHandlers>
   </system.web>