Permalink
Branch: master
Find file Copy path
6300758 Jul 24, 2017
2 contributors

Users who have contributed to this file

@tabassassin @ringt
213 lines (188 sloc) 6.58 KB
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Auxiliary
include Msf::Exploit::Remote::Smtp
include Msf::Auxiliary::Report
include Msf::Auxiliary::Scanner
def initialize
super(
'Name' => 'SMTP User Enumeration Utility',
'Description' => %q{
The SMTP service has two internal commands that allow the enumeration
of users: VRFY (confirming the names of valid users) and EXPN (which
reveals the actual address of users aliases and lists of e-mail
(mailing lists)). Through the implementation of these SMTP commands can
reveal a list of valid users.
},
'References' =>
[
['URL', 'http://www.ietf.org/rfc/rfc2821.txt'],
['OSVDB', '12551'],
['CVE', '1999-0531']
],
'Author' =>
[
'Heyder Andrade <heyder[at]alligatorteam.org>',
'nebulus'
],
'License' => MSF_LICENSE
)
register_options(
[
Opt::RPORT(25),
OptString.new('USER_FILE',
[
true, 'The file that contains a list of probable users accounts.',
File.join(Msf::Config.install_root, 'data', 'wordlists', 'unix_users.txt')
]),
OptBool.new('UNIXONLY', [ true, 'Skip Microsoft bannered servers when testing unix users', true])
])
deregister_options('MAILTO','MAILFROM')
end
def smtp_send(data=nil)
begin
result=''
code=0
sock.put("#{data}")
result=sock.get_once
result.chomp! if(result)
code = result[0..2].to_i if result
return result, code
rescue Rex::ConnectionError, Errno::ECONNRESET, ::EOFError
return result, code
rescue ::Exception => e
print_error("#{rhost}:#{rport} Error smtp_send: '#{e.class}' '#{e}'")
return nil, 0
end
end
def run_host(ip)
users_found = {}
result = nil # temp for storing result of SMTP request
code = 0 # status code parsed from result
vrfy = true # if vrfy allowed
expn = true # if expn allowed
rcpt = true # if rcpt allowed and useful
usernames = extract_words(datastore['USER_FILE'])
cmd = 'HELO' + " " + "localhost" + "\r\n"
connect
result, code = smtp_send(cmd)
if(not result)
print_error("#{rhost}:#{rport} Connection but no data...skipping")
return
end
banner.chomp! if (banner)
if(banner =~ /microsoft/i and datastore['UNIXONLY'])
print_status("#{rhost}:#{rport} Skipping microsoft (#{banner})")
return
elsif(banner)
print_status("#{rhost}:#{rport} Banner: #{banner}")
end
domain = result.split()[1]
domain = 'localhost' if(domain == '' or not domain or domain.downcase == 'hello')
vprint_status("#{ip}:#{rport} Domain Name: #{domain}")
result, code = smtp_send("VRFY root\r\n")
vrfy = (code == 250)
users_found = do_enum('VRFY', usernames) if (vrfy)
if(users_found.empty?)
# VRFY failed, lets try EXPN
result, code = smtp_send("EXPN root\r\n")
expn = (code == 250)
users_found = do_enum('EXPN', usernames) if(expn)
end
if(users_found.empty?)
# EXPN/VRFY failed, drop back to RCPT TO
result, code = smtp_send("MAIL FROM: root\@#{domain}\r\n")
if(code == 250)
user = Rex::Text.rand_text_alpha(8)
result, code = smtp_send("RCPT TO: #{user}\@#{domain}\r\n")
if(code >= 250 and code <= 259)
vprint_status("#{rhost}:#{rport} RCPT TO: Allowed for random user (#{user})...not reliable? #{code} '#{result}'")
rcpt = false
else
smtp_send("RSET\r\n")
users_found = do_rcpt_enum(domain, usernames)
end
else
rcpt = false
end
end
if(not vrfy and not expn and not rcpt)
print_status("#{rhost}:#{rport} could not be enumerated (no EXPN, no VRFY, invalid RCPT)")
return
end
finish_host(users_found)
disconnect
rescue Rex::ConnectionError, Errno::ECONNRESET, Rex::ConnectionTimeout, EOFError, Errno::ENOPROTOOPT
rescue ::Exception => e
print_error("Error: #{rhost}:#{rport} '#{e.class}' '#{e}'")
end
def finish_host(users_found)
if users_found and not users_found.empty?
print_good("#{rhost}:#{rport} Users found: #{users_found.sort.join(", ")}")
report_note(
:host => rhost,
:port => rport,
:type => 'smtp.users',
:data => {:users => users_found.join(", ")}
)
end
end
def kiss_and_make_up(cmd)
vprint_status("#{rhost}:#{rport} SMTP server annoyed...reconnecting and saying HELO again...")
disconnect
connect
smtp_send("HELO localhost\r\n")
result, code = smtp_send("#{cmd}")
result.chomp!
cmd.chomp!
vprint_status("#{rhost}:#{rport} - SMTP - Re-trying #{cmd} received #{code} '#{result}'")
return result,code
end
def do_enum(cmd, usernames)
users = []
usernames.each {|user|
next if user.downcase == 'root'
result, code = smtp_send("#{cmd} #{user}\r\n")
vprint_status("#{rhost}:#{rport} - SMTP - Trying #{cmd} #{user} received #{code} '#{result}'")
result, code = kiss_and_make_up("#{cmd} #{user}\r\n") if(code == 0 and result.to_s == '')
if(code == 250)
vprint_status("#{rhost}:#{rport} - Found user: #{user}")
users.push(user)
end
}
return users
end
def do_rcpt_enum(domain, usernames)
users = []
usernames.each {|user|
next if user.downcase == 'root'
vprint_status("#{rhost}:#{rport} - SMTP - Trying MAIL FROM: root\@#{domain} / RCPT TO: #{user}...")
result, code = smtp_send("MAIL FROM: root\@#{domain}\r\n")
result, code = kiss_and_make_up("MAIL FROM: root\@#{domain}\r\n") if(code == 0 and result.to_s == '')
if(code == 250)
result, code = smtp_send("RCPT TO: #{user}\@#{domain}\r\n")
if(code == 0 and result.to_s == '')
kiss_and_make_up("MAIL FROM: root\@#{domain}\r\n")
result, code = smtp_send("RCPT TO: #{user}\@#{domain}\r\n")
end
if(code == 250)
vprint_status("#{rhost}:#{rport} - Found user: #{user}")
users.push(user)
end
else
vprint_status("#{rhost}:#{rport} MAIL FROM: #{user} NOT allowed during brute...aborting ( '#{code}' '#{result}')")
break
end
smtp_send("RSET\r\n")
}
return users
end
def extract_words(wordfile)
return [] unless wordfile && File.readable?(wordfile)
words = File.open(wordfile, "rb") {|f| f.read}
save_array = words.split(/\r?\n/)
return save_array
end
end