Ace Your PT0-003 PenTest+ Exam

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.”

The Nmap command nmap -sv -sT -p- 192.168.1.0/24 is designed to discover services on a network. Here is a breakdown of the command and its purpose:

Command Breakdown:

nmap: The network scanning tool.

-sV: Enables service version detection. This option tells Nmap to determine the version of the services running on open ports.

-sT: Performs a TCP connect scan. This is a more reliable method of scanning as it completes the TCP handshake but can be easily detected by firewalls and intrusion detection systems.

-p-: Scans all 65535 ports. This ensures a comprehensive scan of all possible TCP ports.

192.168.1.0/24: Specifies the target network range (subnet) to be scanned.

Purpose of the Scan:

Service Discovery (Answer: C): The primary purpose of this scan is to discover which services are running on the network's hosts and determine their versions. This information is crucial for identifying potential vulnerabilities and understanding the network's exposure.

A screenshot of a computer Description automatically generated

A screenshot of a computer screen Description automatically generated

Most likely vulnerability: Perform a SSRF attack against App01.example.com from CDN.example.com.

The scenario suggests that the CDN network (with a WAF) can be used to perform a Server-Side Request Forgery (SSRF) attack. Since the penetration tester has the pentester workstation interacting through the CDN/WAF and the production network is behind it, the most plausible attack vector is to exploit SSRF to interact with the internal services like App01.example.com.

Two best remediation options:

Restrict direct communications to App01.example.com to only approved components.

Require an additional authentication header value between CDN.example.com and App01.example.com.

Restrict direct communications to App01.example.com to only approved components: This limits the exposure of the application server by ensuring that only specified, trusted entities can communicate with it.

Require an additional authentication header value between CDN.example.com and App01.example.com: Adding an authentication layer between the CDN and the app server helps ensure that requests are legitimate and originate from trusted sources, mitigating SSRF and other indirect attack vectors.

Nmap Scan Observations:

CDN/WAF shows open ports for HTTP and HTTPS but filtered for MySQL, indicating it acts as a filtering layer.

App Server has open ports for HTTP, HTTPS, and filtered for MySQL.

DB Server has all ports filtered, typical for a database server that should not be directly accessible.

These findings align with the SSRF vulnerability and the appropriate remediation steps to enhance the security of internal communications.