JS/C#/ASP 防止sql注入

SQL注入式攻击是利用是指利用设计上的漏洞，在目标服务器上运行Sql命令以及进行其他方式的攻击
动态生成Sql命令时没有对用户输入的数据进行验证是Sql注入攻击得逞的主要原因。
比如：
如果你的查询语句是select * from admin where username='"&user&"' and password='"&pwd&"'"

那么，如果我的用户名是：1' or '1'='1
那么，你的查询语句将会变成：
select * from admin where username='1 or '1'='1' and password='"&pwd&"'"
这样你的查询语句就通过了，从而就可以进入你的管理界面。

所以防范的时候需要对用户的输入进行检查。特别式一些特殊字符，比如单引号，双引号，分号，逗号，冒号，连接号等进行转换或者过滤。

需要过滤的特殊字符及字符串有：
net user
xp_cmdshell
/add
exec master.dbo.xp_cmdshell
net localgroup administrators
select
count
Asc
char
mid
'
:
"
insert
delete from
drop table
update
truncate
from
%

下面是我写的两种关于解决注入式攻击的防范代码，供大家学习参考！
js版的防范SQL注入式攻击代码～：

[CODE START]
<script language="javascript">
<!--
var url = location.search;
var re=/^\?(.*)(select%20|insert%20|delete%20from%20|count\(|drop%20table|update%20truncate%20|asc\(|mid\(|char\(|xp_cmdshell|exec%20master|net%20localgroup%20administrators|\"|:|net%20user|\'|%20or%20)(.*)$/gi;
var e = re.test(url);
if(e) {
alert("地址中含有非法字符～");
location.href="error.asp";
}
//-->
<script>
[CODE END]

asp版的防范SQL注入式攻击代码～：
[CODE START]
<%
On Error Resume Next
Dim strTemp

If LCase(Request.ServerVariables("HTTPS")) = "off" Then
strTemp = "http://"
Else
strTemp = "https://"
End If

strTemp = strTemp & Request.ServerVariables("SERVER_NAME")
If Request.ServerVariables("SERVER_PORT") <> 80 Then strTemp = strTemp & ":" & Request.ServerVariables("SERVER_PORT")

strTemp = strTemp & Request.ServerVariables("URL")

If Trim(Request.QueryString) <> "" Then strTemp = strTemp & "?" & Trim(Request.QueryString)

strTemp = LCase(strTemp)

If Instr(strTemp,"select%20") or Instr(strTemp,"insert%20") or Instr(strTemp,"delete%20from") or Instr(strTemp,"count(") or Instr(strTemp,"drop%20table") or Instr(strTemp,"update%20") or Instr(strTemp,"truncate%20") or Instr(strTemp,"asc(") or Instr(strTemp,"mid(") or Instr(strTemp,"char(") or Instr(strTemp,"xp_cmdshell") or Instr(strTemp,"exec%20master") or Instr(strTemp,"net%20localgroup%20administrators") or Instr(strTemp,":") or Instr(strTemp,"net%20user") or Instr(strTemp,"'") or Instr(strTemp,"%20or%20") then
Response.Write "<script language='javascript'>"
Response.Write "alert('非法地址！！');"
Response.Write "location.href='error.asp';"
Response.Write "<script>"
End If
%>
[CODE END]

C# 检查字符串,防SQL注入攻击
这个例子里暂定为=号和'号
bool CheckParams(params object[] args)
{
    string[] Lawlesses={"=","'"};
    if(Lawlesses==null||Lawlesses.Length<=0)return true;
    //构造正则表达式,例:Lawlesses是=号和'号,则正则表达式为 .*[=}'].* (正则表达式相关内容请见MSDN)
    //另外,由于我是想做通用而且容易修改的函数,所以多了一步由字符数组到正则表达式,实际使用中,直接写正则表达式亦可;
    string str_Regex=".*[";
    for(int i=0;i< Lawlesses.Length-1;i++)
        str_Regex+=Lawlesses[i]+"|";
    str_Regex+=Lawlesses[Lawlesses.Length-1]+"].*";
    //
    foreach(object arg in args)
    {
        if(arg is string)//如果是字符串,直接检查
        {
            if(Regex.Matches(arg.ToString(),str_Regex).Count>0)
            return false;
        }
        else if(arg is ICollection)//如果是一个集合,则检查集合内元素是否字符串,是字符串,就进行检查
        {
            foreach(object obj in (ICollection)arg)
            {
                if(obj is string)
                {
                    if(Regex.Matches(obj.ToString(),str_Regex).Count>0)
                    return false;
                }
            }
        }
    }
    return true;

/// <summary>
/// 当有数据时交时，触发事件
/// </summary>
/// <param name="sender"> </param>
/// <param name="e"> </param>
protected void Application_BeginRequest(Object sender, EventArgs e)
{
//遍历Post参数，隐藏域除外
foreach (string i in this.Request.Form)
{
if (i == "__VIEWSTATE") continue;
this.goErr(this.Request.Form[i].ToString());
}
//遍历Get参数。
foreach (string i in this.Request.QueryString)
{
this.goErr(this.Request.QueryString[i].ToString());

}

}

/// <summary>
///SQL注入过滤
/// </summary>
/// <param name="InText">要过滤的字符串 </param>
/// <returns>如果参数存在不安全字符，则返回true </returns>
public bool SqlFilter(string InText)
{
string word = "and |exec |insert |select |delete |update |chr |mid |master |or |truncate |char |declare |join |cmd | |' |--";//这里加要过滤的SQL字符
if (InText == null)
return false;
foreach (string i in word.Split(' |'))
{
if ((InText.ToLower().IndexOf(i + " ") > -1) | | (InText.ToLower().IndexOf(" " + i) > -1))
{
return true;
}
}
return false;
}

/// <summary>
/// 校验参数是否存在SQL字符
/// </summary>
/// <param name="tm"> </param>
private void goErr(string tm)
{
if (SqlFilter(tm))
{
Response.Write(" <script>window.alert('参数存在不安全字符');"+" </"+"script>");
}
}

protected void Application_BeginRequest(Object sender, EventArgs e)
{
//SQL防注入
string Sql_1 = "exec |insert+ |select+ |delete |update |count |chr |mid |master+ |truncate |char |declare |drop+ |drop+table |creat+ |creat+table";
string Sql_2 = "exec+ |insert+ |delete+ |update+ |count( |count+ |chr+ |+mid( |+mid+ |+master+ |truncate+ |char+ |+char( |declare+ |drop+ |creat+ |drop+table |creat+table";
string[] sql_c = Sql_1.Split(' |');
string[] sql_c1 = Sql_2.Split(' |');

if (Request.QueryString != null)
{
foreach (string sl in sql_c)
{
if (Request.QueryString.ToString().ToLower().IndexOf(sl.Trim()) >= 0)
{
Response.Write("警告！你的IP已经被记录!");//
Response.Write(sl);
Response.Write(Request.QueryString.ToString());
Response.End();
break;
}
}
}

if (Request.Form.Count > 0)
{
string s1 = Request.ServerVariables["SERVER_NAME"].Trim();//服务器名称
if (Request.ServerVariables["HTTP_REFERER"] != null)
{
string s2 = Request.ServerVariables["HTTP_REFERER"].Trim();//http接收的名称
string s3 = "";
if (s1.Length > (s2.Length - 7))
{
s3 = s2.Substring(7);
}
else
{
s3 = s2.Substring(7, s1.Length);
}
if (s3 != s1)
{
Response.Write("你的IP已被记录！警告！");//
Response.End();
}
}
}
}

#region SQL注入式攻击代码分析
/// <summary>
/// 处理用户提交的请求
/// </summary>
private void StartProcessRequest()
{
try
{
string getkeys = "";
string sqlErrorPage = "../default.aspx";//转向的错误提示页面
if (System.Web.HttpContext.Current.Request.QueryString != null)
{

for (int i = 0; i < System.Web.HttpContext.Current.Request.QueryString.Count; i++)
{
getkeys = System.Web.HttpContext.Current.Request.QueryString.Keys[i];
if (!ProcessSqlStr(System.Web.HttpContext.Current.Request.QueryString[getkeys]))
{
System.Web.HttpContext.Current.Response.Redirect(sqlErrorPage);
System.Web.HttpContext.Current.Response.End();
}
}
}
if (System.Web.HttpContext.Current.Request.Form != null)
{
for (int i = 0; i < System.Web.HttpContext.Current.Request.Form.Count; i++)
{
getkeys = System.Web.HttpContext.Current.Request.Form.Keys[i];
if (getkeys == "__VIEWSTATE") continue;
if (!ProcessSqlStr(System.Web.HttpContext.Current.Request.Form[getkeys]))
{
System.Web.HttpContext.Current.Response.Redirect(sqlErrorPage);
System.Web.HttpContext.Current.Response.End();
}
}
}
}
catch
{
// 错误处理: 处理用户提交信息!
}
}
/// <summary>
/// 分析用户请求是否正常
/// </summary>
/// <param name="Str">传入用户提交数据 </param>
/// <returns>返回是否含有SQL注入式攻击代码 </returns>
private bool ProcessSqlStr(string Str)
{
bool ReturnValue = true;
try
{
if (Str.Trim() != "")
{
string SqlStr = "and |exec |insert |select |delete |update |count |* |chr |mid |master |truncate |char |declare";

string[] anySqlStr = SqlStr.Split('|');
foreach (string ss in anySqlStr)
{
if (Str.ToLower().IndexOf(ss.Trim()) >= 0)
{
ReturnValue = false;
break;
}
}
}
}
catch
{
ReturnValue = false;
}
return ReturnValue;
}
#endregion