ASP防SQL注入攻击技巧实例详解

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asp项目,在sql查询使用字符串拼接情况下，会受到sql注入攻击，可以使用敏感词过滤和参数化语句进行修改。

敏感词过滤

Dim Fy_Post,Fy_Get,Fy_In,Fy_Inf,Fy_Xh,Fy_db,Fy_dbstr,Kill_IP,WriteSql
'自定义需要过滤的字串,用 "|" 分隔
Fy_In = "'|;|and|(|)|exec|insert|select|delete|update|count|*|%|chr|mid|master|truncate|char|declare|exist|drop"
Kill_IP=True
WriteSql=True           
'----------------------------------
Fy_Inf = split(Fy_In,"|")
'--------POST部份------------------
If Request.Form<>"" Then
    For Each Fy_Post In Request.Form
        For Fy_Xh=0 To Ubound(Fy_Inf)
            If Instr(LCase(Request.Form(Fy_Post)),Fy_Inf(Fy_Xh))<>0 Then
            Response.Redirect "/index.asp"
            Response.End
            End If
        Next
    Next
End If
If Request.QueryString<>"" Then
    For Each Fy_Get In Request.QueryString
        For Fy_Xh=0 To Ubound(Fy_Inf)
            If Instr(LCase(Request.QueryString(Fy_Get)),Fy_Inf(Fy_Xh))<>0 Then
            Response.Redirect "/index.asp"
            Response.End
            End If
        Next
    Next
End If

对敏感词URL进行过滤,重定位或进行其他处理

参数化

Public Function execSqlOpen(connect,cursorType,lockType,args())
      set cmdTemp = server.CreateObject("ADODB.Command")
          cmdTemp.ActiveConnection = connect
          cmdTemp.Prepared = true
          cmdTemp.CommandText = args(0)
    Dim i  
        For i = 1 To UBound(args)  
           set paramTemp = cmdTemp.CreateParameter("",201,1,Len(args(i))+10,args(i))
        cmdTemp.Parameters.Append paramTemp
        Next   
          set rsTemp=server.CreateObject("adodb.recordset")
          rsTemp.open cmdTemp,,cursorType,lockType
          set execSqlOpen = rsTemp
end function
 
Public Function execSqlExecute(connect,args())
      set cmdTemp = server.CreateObject("ADODB.Command")
          cmdTemp.ActiveConnection = connect
          cmdTemp.Prepared = true
          cmdTemp.CommandText = args(0)
    Dim i
        For i = 1 To UBound(args)  
           set paramTemp = cmdTemp.CreateParameter("",201,1,Len(args(i))+10,args(i))
        cmdTemp.Parameters.Append paramTemp
        Next   
          set execSqlExecute = cmdTemp.execute
end function

封装这两个函数,然后进行修改

• 1.使用open的调用execSqlOpen(需要调用close,视原代码是否close决定),使用execute的调用execSqlExecute(不调用close)
• 2.需要返回值的用set 一个变量接收,不需要的用call调用
• 3.表名动态拼接的,无法使用占位符,使用原始拼接方式
• 4.使用like的,内部使用?占位,外部使用字符串拼接前后%("%"&keyword&"%")

例子如下:

open普通查询

sql="select * from table where column='"&column&"'"
set rs=server.CreateObject("ADODB.recordset")
rs.Open sql,conn,1,1
=>
dim args
args = Array("select * from table where column = ?",column)
set rs = execSqlOpen(conn,1,1,args)

动态参数查询

sql="select * from table where 1=1 and column1='"&request("column1")&"'"
if column2<>"" then
sql=sql&" and column2 like '%"&column2&"%'"
end if
if column3<>"" then
sql=sql&" and column3 ="&column3&""
end if
sql=sql&" order by column4 desc;"
Set rs= Server.CreateObject("ADODB.Recordset")
rs.open sql,conn,1,1
=>
dim args
args = Array("select * from table where 1=1 and column1=?",request("column1"))
if column2<>"" then
args(0)=args(0)&" and column2 like ?"
ReDim Preserve args(UBound(args)+1)
args(UBound(args)) = "%"&column2&"%"
end if
if column3<>"" then
args(0)=args(0)&" and column3 =?"
ReDim Preserve args(UBound(args)+1)
args(UBound(args)) = column3
end if
args(0)=args(0)&" order by column4 desc;"
set rs = execSqlOpen(conn,1,1,args)

table动态

Set Rs_t=Conn.Execute("Select column From "&table&" where column1="&column1)
=>
dim args
args = Array("Select column From "&table&" where column1=?",column1)
set Rs_t = execSqlExecute(conn,args)

执行查询

set rs=conn.execute("select * from table where column="&request("column"))
=>
dim args
args = Array("select * from table where column = ?",request("column"))
set rs = execSqlExecute(conn,args)

执行更新

conn.execute("update table set column = '"&column&"'")
=>
dim args
args = Array("update table set column = ?",column)
call execSqlExecute(conn,args)

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