PenTest+ PT0-002 CompTIA Study Notes

The correct Python script for implementing a simple TCP port scanner that checks for open ports from 1000 to 2000 is option A. This script uses a for loop to iterate through the range of ports, creates a socket object for each port using the socket.AF_INET address family (indicating IPv4) and socket.SOCK_STREAM socket type (indicating TCP), and attempts to connect to each port. If the connection attempt (connect_ex) returns 0, it indicates the port is open, and the script prints a message stating that the port is open before closing the socket. The other options contain syntax errors, use incorrect socket types, or have incorrect ranges that do not fully cover the specified ports.

The PHP file uploaded by the penetration tester allows for Remote Code Execution (RCE) by executing the command supplied through the cmd POST parameter. To exploit this, the penetration tester needs to send a POST request to the PHP file with the command they want to execute.

Among the given options, Option A is the most suitable for achieving RCE:

It uses Python's requests library to send a POST request, which is appropriate because the PHP script expects data through the POST method.

The data parameter in the requests.post function is correctly formatted as a dictionary, which is the expected format for sending form data in POST requests. It includes the key cmd with the value id, which is a common command used to display the current user ID and group ID.

The only minor issue with Option A is that it prints the entire response object, which includes not just the response content but also metadata like status code and headers. To print just the response content (which would include the output of the id command), appending .text to the requests.post call would be more precise, but this is a small detail and does not affect the execution of the command.

The other options have various issues:

Option B is close but has a syntax error in the data argument. It uses parentheses () instead of curly braces {} for the dictionary, and also lacks the .text at the end to print the response content.

Options C and D use the requests.get method, which is not suitable in this scenario because the PHP script is expecting data through the POST method, not the GET method. Additionally, Option D has a syntax error similar to Option B.

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.

The script is performing a port scan on the network 192.168.0.0/24, by testing the connectivity of three ports (80, 110, 25) on each IP address in the range 1-254. A port scan is a technique used to identify open ports and services on a target host or network. It can be used for reconnaissance, vulnerability assessment, or penetration testing. References:

•The Official CompTIA PenTest+ Instructor Guide (Exam PT0-002) eBook, Chapter 3, Lesson 3.2, Topic 3.2.2: Perform a port scan

•PowerShell TCP port scanner, Stack Overflow answer by postanote

•PowerShell Basics: How to Scan Open Ports Within a Network, Tech Community blog by Anthony Bartolo