Cybersecurity & Information Security

Wireshark for Beginners: A Structured Process for PCAP File Analysis

6 min readPublished: August 5, 2026

Professional visual illustration of PCAP analysis in Wireshark in Network Security Monitoring

Quick answer

PCAP analysis in Wireshark is performed by mapping Flow, times, protocols, DNS/TLS/HTTP, and the context of the asset. A single packet or connection is partial evidence, so a sequence is built and verified against additional sources.

Network traffic provides a viewpoint that is not solely dependent on the endpoint. It allows identifying who talked to whom, using which protocol, in what order, and in what volume, but requires an understanding of the visibility limits and encryption. This article focuses on PCAP analysis in Wireshark and is intended for SOC and PT students. The goal is to provide a working method that can be applied in practice, in professional interviews, and in a work environment, without settling for a dictionary definition.

The main challenge is that data is almost always partial. Protocol Hierarchy, Endpoints, Conversations can point to a direction, but their meaning depends on time, asset, user, and expected activity. Therefore, we will build the examination around an investigation question, required evidence, and a clear criterion for completion.

The practical scenario in the article is: educational PCAP analysis with DNS, HTTP, and TCP. All examples are lab data or process descriptions. When it comes to Penetration Testing, Web, or Cloud, work only with explicit authorization, a defined Scope, and the ability to stop the test.

Preparing the Analysis Environment

An investigation of PCAP analysis in Wireshark begins with formulating a Hypothesis: what behavior explains the finding, and what evidence will confirm or refute it. Then, expand the time window, verify the entities, and look for a sequence before and after the event.

Good correlation combines at least two types of information from Protocol Hierarchy, Endpoints, Conversations, Display Filters, Follow Stream, Expert Information. For each finding, state what it proves, what it does not prove, and what the next step is. If the data is insufficient, mark it as Unknown and do not turn absence of evidence into evidence of absence.

Statistics and Protocol Hierarchy

The topic 'Statistics and Protocol Hierarchy' is a key part of working on PCAP analysis in Wireshark. It is recommended to break it down into three questions: what is the input, what decision do you want to make, and what evidence is sufficient to justify it. These questions prevent automatic use of the tool without understanding the purpose.

In practice, record the Protocol Hierarchy, Endpoints, Conversations, Display Filters, Follow Stream, compare to expected behavior, and define at least one Pivot. The result should be verifiable by another analyst, including limitations and next steps.

Endpoints and Conversations

The topic 'Endpoints and Conversations' is a key part of working on PCAP analysis in Wireshark. It is recommended to break it down into three questions: what is the input, what decision do you want to make, and what evidence is sufficient to justify it. These questions prevent automatic use of the tool without understanding the purpose.

Filters and Streams

The topic 'Filters and Streams' is a key part of working on PCAP analysis in Wireshark. It is recommended to break it down into three questions: what is the input, what decision do you want to make, and what evidence is sufficient to justify it. These questions prevent automatic use of the tool without understanding the purpose.

Documenting Findings and Timeline

Timeline is the backbone of PCAP analysis in Wireshark. Normalize times to UTC or explicitly state the time zone, save both Event time and Ingestion time, and connect events by stable identifiers. The line should include time, source, entity, action, result, and reliability.

A gap or contradiction is not a document error but a finding. Clock drift, reception delay, NAT, reuse of PID or continuous Session can change order. Therefore, state uncertainty ranges and maintain a link back to the raw evidence.

Unique Examination Focus Areas

For this topic, it is recommended to build a focused evidence map in advance. The main examination focus areas are: Protocol Hierarchy, Endpoints, Conversations, Display Filters, Follow Stream, Expert Information. This list is not an automatic Checklist; each item is chosen because it can link an entity, action, and time, or explain legitimate behavior.

Protocol Hierarchy: Define the expected value, what would be considered anomalous, and what additional source would confirm the finding.
Endpoints: Define the expected value, what would be considered anomalous, and what additional source would confirm the finding.
Conversations: Define the expected value, what would be considered anomalous, and what additional source would confirm the finding.
Display Filters: Define the expected value, what would be considered anomalous, and what additional source would confirm the finding.
Follow Stream: Define the expected value, what would be considered anomalous, and what additional source would confirm the finding.
Expert Information: Define the expected value, what would be considered anomalous, and what additional source would confirm the finding.

When one of the focus areas is unavailable, document the gap and choose an alternative. For example, if a Process identifier is not stable, you can use time, Host, User, and Parent; if Payload is encrypted, use Metadata, volume, frequency, and TLS/DNS context.

Recommended Workflow

Define Scope and one working question regarding PCAP analysis in Wireshark.
Record the data sources and required evidence: Protocol Hierarchy, Endpoints, Conversations, Display Filters.
Create a short Baseline of normal behavior or expected outcome.
Perform the minimal test in a lab environment and save time, input, and output.
Build a Timeline or comparison table and separate fact from interpretation.
Pivot to an additional source to confirm or refute the initial explanation.
Summarize the decision, limitations, recommended action, and Retest criterion.

Practical Scenario

The chosen scenario is educational PCAP analysis with DNS, HTTP, and TCP. The purpose of the exercise is not to prove attack capability, but to practice collecting, comparing, and documenting safely. Before starting, define simulated data, a time window, and an expected outcome.

At the end of the exercise, a product should be submitted that another analyst or tester can review: a screenshot or Export of the evidence, a short Timeline, an initial assumption, corroborating evidence, a limitation, and a recommendation. When there is insufficient evidence, the correct conclusion is that the scenario was not proven.

Stage	What to Perform	Output
Preparation	Define Scope, time, and objective. Note which fields or evidence from Protocol Hierarchy, Endpoints, Conversations are expected to appear.	Short test plan
Data Creation	Perform a safe and simulated action related to PCAP analysis in Wireshark, without real information or impact on a production system.	Controlled event/Request/Flow
Collection	Collect the raw evidence and context from an additional source. Verify Time zone, identifiers, and integrity.	Two linked pieces of evidence
Analysis	Write what each piece of evidence proves, what it does not prove, and what the legitimate possible explanation is.	Interim conclusion
Completion	Choose closure, escalation, Finding or Tuning; add recommendation and Retest.	Documented output

Practical Checklist

Check and document: the five components of the Flow.
Check and document: start time, duration, and volume.
Check and document: DNS name and TLS metadata.
Check and document: HTTP method, host, and URI when visible.
Check and document: TCP flags and stream.
Check and document: connection to Host and Process.
State Time zone, tool version, and collection time.
Save the raw data before filtering or modification.
Write what the finding proves and what is still unknown.
Define owner and follow-up action with a deadline.

Common Mistakes

Confusing Capture Filter with Display Filter.
Inferring content when traffic is encrypted.
Analyzing IP without DNS/TLS context.
Ignoring NAT or Proxy.
Focusing on a single Packet.
Not saving the original Capture.

Summary and CTA

Wireshark for beginners: A structured process for PCAP file analysis is a topic that connects technical knowledge to work discipline. Start with a question, collect only relevant evidence, maintain context and time, and choose an action that can be justified and re-tested.

In HPI's Cybersecurity & AI program, these principles are practiced using systems, logs, and labs. A natural next step is to move on to the linked articles, perform the lab exercise, and save the output as part of a professional portfolio.

FAQ

Does PCAP analysis in Wireshark alone prove an attack or vulnerability?

No. It provides a signal or finding that requires context, validation, and an additional source. A professional conclusion relies on a sequence of evidence and consistency with expected behavior.

What to do when some data is missing?

Document the missing data, check for an alternative source, and reduce the confidence level. Do not fill in fields by conjecture or present Unknown as normal.

How long should evidence be kept?

The time depends on policy, regulation, cost, and the type of event. It is important to define Retention, Legal hold, and the ability to export evidence in a verifiable format in advance.

How to practice without risking a real system?

Use virtual machines, simulated data, CTF, or a dedicated lab. For authorized tests, define Scope, Stop conditions, and backup before starting work.