在Global.asax文件里实现通用防SQL注入漏洞程序(适应于post/get请求)

首先，创建一个SQLInjectionHelper类完成恶意代码的检查
代码如下：

复制代码 代码如下:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Text.RegularExpressions;
///

///SQLInjectionHelper 的摘要说明
///

public class SQLInjectionHelper
{
///

/// 获取Post的数据
///

///
///
public static bool ValidUrlData(string request)
{
bool result = false;
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;
}
}
}
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;
}
///

/// 验证是否存在注入代码
///

///
///
private static bool ValidData(string inputData)
{
//验证inputData是否包含恶意集合
if (Regex.IsMatch(inputData, GetRegexString()))
{
return true;
}
else
{
return false;
}
}
///

/// 获取正则表达式
///

///
private static string GetRegexString()
{
//构造SQL的注入关键字符
string[] strChar = { "and", "exec", "insert", "select", "update", "delete", "count", "from", "drop", "asc", "or", "char", "%", ";", ":", "\'", "\"", "-", "chr", "master", "mid", "truncate", "declare", "char", "SiteName", "/add", "xp_cmdshell", "net user", "net localgroup administrators", "exec master.dbo.xp_cmdshell" };
string str_Regex = ".*(";
for (int i = 0; i < strChar.Length - 1; i++)
{
str_Regex += strChar[i] + "|";
}
str_Regex += strChar[strChar.Length - 1] + ").*";
return str_Regex;
}
}

有此类后即可使用Global.asax中的Application_BeginRequest(object sender, EventArgs e)事件来实现表单或者URL提交数据的获取，获取后传给SQLInjectionHelper类ValidUrlData方法来完成检查
代码如下

复制代码 代码如下:

protected 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();
}
}

下面以一个小程序测试：
创建一个页面，如下

复制代码 代码如下:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

onclick="btnPost_Click" />

分别添加单击事件，如下

复制代码 代码如下:

protected void btnPost_Click(object sender, EventArgs e)
{
}
protected void btnGet_Click(object sender, EventArgs e)
{
Response.Redirect("Default.aspx?a=1&b=2&c=3");
}

在文本框中输入非法字符串，无论post请求还是get请求，都会被防SQL注入程序所截获

                      图1 测试防SQL注入程序的页面

                               图2 错误信息