Deep packet inspection (DPI) analyzes the data part (and possibly also the header) of a packet as it passes an inspection point, searching for protocol non-compliance, viruses, spam, intrusions, or defined criteria to decide whether the packet may pass or if it needs to be routed to a different destination. Stateful inspection, on the other hand, tracks the state of active connections and determines which network packets to allow through the firewall. While stateful inspection tracks the state of connections (Layer 4 - transport layer), DPI goes further by examining the payload of the packet (Layer 7 - application layer).

Cisco’s official documentation and cybersecurity courses would explain the differences between deep packet inspection and stateful inspection, including their respective layers of operation.

A phishing attack often involves sending emails that appear to be from reputable sources with the goal of inducing individuals to reveal personal information, such as passwords and credit card numbers. In this case, the email with the subject “price deduction” containing a malicious attachment is designed to trick the recipient into opening the attachment, which can then execute harmful software on their device

When analyzing Wireshark traffic for potential attacks, an engineer should look for patterns that indicate abnormal behavior, such as:

Excessive Requests: A high number of requests over a short period could suggest an attempt to overwhelm the server, known as an HTTP flood.

Status Codes: Repeated 403 Forbidden responses may indicate that the server is rejecting requests due to a security rule being triggered.

Request Types: A mix of GET and POST requests could be used in various attack scenarios, including bandwidth flooding or cache bypassing.

 Indicators of Compromise (IoC) are pieces of forensic data, such as system log entries or files, that suggest an intrusion may have occurred. Indicators of Attack (IoA) are signs that an attack may be underway, allowing organizations to take action before any potential breach occurs.

The CBROPS course materials cover the concepts of IoC and IoA, explaining how they are used in cybersecurity operations to detect and prevent security incidents.

A file hash is a unique identifier that is used to detect a specific file. It is generated by running a file through a cryptographic hash function, which produces a string of characters that represents the contents of the file. If even a single bit in the file changes, the resulting hash will be different, making it an effective way to identify files uniquely.

Resource exhaustion is an evasion technique where an attacker overwhelms a system with a high volume of requests from multiple sources. This can cause the system to become overloaded and unable to process legitimate traffic, potentially allowing the attacker to bypass security measures like intrusion detection systems.

References := The answers are based on the knowledge from the Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) course material, which covers various cybersecurity concepts, including file identification methods, application control technologies, firewall utilities, and evasion techniques

 In the context of phishing emails, the threat actor is the entity that is responsible for initiating the threat, which in this case is the sender of the phishing emails. The sender is impersonating the HR department to deceive the receiver into believing that the emails are legitimate

 A denial-of-service attack represents the evasion technique of resource exhaustion, where the attacker overwhelms a system’s resources, making the system unusable and unable to handle legitimate requests. References := Cisco Cybersecurity Source Documents