Quick answer: Wireshark is an open source analysis tool that captures and inspects network traffic at the packet level. It is used in both troubleshooting and security analysis: it helps see unencrypted credential leakage, suspicious connections, malicious traffic and protocol anomalies. In a penetration test it is a tool for network reconnaissance and evidence gathering; in incident response it is a tool for understanding attack traffic. The core concepts: packet capture, display filters and stream following.

What is Wireshark used for?

Everything happening on the network flows as packets. Wireshark captures these packets and parses each at the protocol level: source, destination, protocol, content. So you see what is really happening on the network. It reveals at the packet level why an application is slow, where a connection goes, or whether a credential passed unencrypted.

Security wise Wireshark is two way: in a penetration test it is used to gather information from network traffic and capture evidence; in defense and incident response it is used to understand the network traces of an attack.

Core concepts

Concept Description
Packet capture Recording traffic from a network interface
Display filter Filtering relevant packets (e.g. protocol, IP, port)
Stream following Combining the full data flow of a connection
Protocol dissection The detail of each layer (TCP, HTTP, DNS)
Statistics Conversations, endpoints, protocol distribution

What to look for in security analysis?

  • Credentials and sensitive data passing unencrypted (HTTP, FTP, Telnet).
  • Connections to unusual destinations (suspected command and control traffic).
  • Protocol anomalies and unexpected port usage.
  • DNS tunneling and data exfiltration patterns.
  • Repeated or automated looking traffic.

An important limit: most modern traffic is encrypted (TLS), so Wireshark shows the headers and metadata rather than the content. Even so, connection patterns, destinations and timing are valuable clues in security analysis.

The KAOS and DSET approach

In penetration testing and incident response DSET analyzes network traffic and ties findings such as unencrypted credential leakage, suspicious connections and protocol anomalies to evidence. Our KAOS includes a live traffic capture capability and helps gather network level evidence. Our goal is to show at the packet level, with evidence, what is really happening on the network. We handle the traffic we capture so as to preserve the chain of custody.

Related reading: TLS SSL configuration hardening, DNS security tunneling hijacking, SIEM and SOC, cyber incident response playbook NIST 800-61, network reconnaissance with Nmap, AV EDR evasion and detection.

Frequently asked questions

Can Wireshark read encrypted traffic? No, it cannot directly read the content of encrypted (TLS) traffic. But it sees the connection headers and metadata: source, destination, port, timing, traffic volume. Even this metadata is valuable in security analysis; for example, an encrypted connection to an unusual destination can raise suspicion of command and control traffic. Seeing the content requires special cases where the keys are available.

Is Wireshark an attack tool? Wireshark is a legitimate network analysis and troubleshooting tool used by both network administrators and security teams. In a penetration test it is a tool for gathering evidence, in defense it is a tool for understanding attack traces. Capturing traffic requires access to the relevant network segment; capturing someone else's traffic without authorization creates legal liability.

How do I find unencrypted credentials on the network? With Wireshark, by filtering the relevant protocols (unencrypted protocols such as HTTP, FTP, Telnet) and following the stream. Because these protocols carry credentials in plaintext, passwords can appear in the traffic. This is a serious risk in an environment still using unencrypted protocols, and the finding shows these protocols should be replaced with encrypted alternatives (HTTPS, SFTP, SSH).

Sources

For network traffic analysis and incident response, you can talk to our team at Ankara Hacettepe Technopark. Contact DSET.