PCAP What It Is & What You Need To Know

Network health and safety have become a primary concern for many enterprises as cyberattacks become more and more common every year. In 2022 alone, cyberattacks increased by 38%, according to statistics. 

This figure prompts admins and cybersecurity specialists to develop more comprehensive ways to patrol their networks.

One of these ways is PCAP. This process sweeps networks and locates valuable data that can be used to monitor, troubleshoot, and tighten security. 

If you’re curious about PCAP, what it is, and what you need to know, here’s the lowdown for beginners.

All You Need to Know About PCAP

When data travel on a network, they’re divided into small segments called packets. The process that intercepts and records these traveling data packets is an Application Programming Interface (API) known as Packet Capture (PCAP).

Packets are captured and converted into readable files, so cyber specialists and security teams can analyze them. 

Moreover, cybersecurity teams use PCAP to monitor network behavior, determine malicious activity, identify congestion and misuse, and troubleshoot issues that affect daily operations.

PCAP is made of raw code, irrefutable evidence of network activity. It’s even called “the ultimate resource of truth” in network analysis.  

How Does PCAP Work?

PCAP begins with Sniffers, specialized devices like taps or software tools that run on a network-connected computer. 

A sniffer is what its name suggests; it sniffs out packets. After it has located them, it “captures” the packets by copying them and creating PCAP files.

These files are data arranged into a readable format that’s easier to understand. It even has a header and a time stamp for when it was captured. After that, the files are then filtered and readied for analysis.

Users then open these files utilizing Wireshark, tcpdump, and other tools. They provide an interface to see, study, and configure the captured data.

PCAP takes several forms, depending on the tools used to make them. These formats are:

• Libpcap. This is intended for MAC OS and Linux-run devices.
• Npcap. This format is for Windows computers. Wireshark uses it.
• PCAPng. This is a recent format that has a broader scripting capacity.
• WinPcap. This is another format used in Windows computers. It’s typically used in remote cases.

How Important is PCAP Analysis?

Every 39 seconds, a hacking incident occurs. Also, in 2019, a staggering 22.5 million records from different companies and organizations were stolen daily. All these incidents echo the need for sturdy network protection. 

Admins need to cover virtually all details of the network they manage. They have to monitor daily traffic, especially since these cyberattacks could pop up quickly.

PCAP analysis allows admins and other specialists to sift through all the data in the traffic and record them without impacting the network’s speed. The filtered data gives the entire network visibility and exposes anomalous activities. 

There are more specific reasons why you should regularly analyze PCAP files. Here are some of them:

Assuring Security

PCAP helps hunt network intrusions, threats, and other suspicious activity. When PCAP files are interpreted correctly, they can also identify different types of malware.

Specifically, cybersecurity teams use PCAP to determine an attack’s destination, its host details, and the payload it carries to remediate the problem. 

Traffic Detection

PCAP tracks data volume, transactions, and traffic. Since it gives users a detailed bird’s eye view of the network, it can spot unusual spikes. PCAP helps identify its root, giving cybersecurity teams critical insights and helping them judge whether the spike is a cause for concern.

Troubleshooting

Capturing data packets helps users know about a network’s performance and overall health. PCAP grants real-time visibility, allowing them to monitor many applications instantly and avoid downtime. 

Packet Capturing Tools

To experience the benefits of data packet capture, you must create a .pcapfile first. As mentioned, this file displays information that users can see and interpret to maintain the network. 

Wireshark

Wireshark is a vulnerability scanning tool that’s often used for troubleshooting. It works with most operating systems and is built with powerful features. 

Wireshark has a graphical interface. One of its main features is a selection of display filters, which presents options for viewing PCAP files. It also lets you use PCAP files for real-time and offline analysis.

Unfortunately, Wireshark is not for beginners. You have to be an advanced user to utilize it fully. 

However, Wireshark is open-sourced and free to use. There are no pricing plans or subscriptions. Regardless of its challenging interface, it’s still one of the most commonly used software for PCAP.

tcpdump

Tcpdump is another free and open-sourced tool that analyzes networks.

Unlike Wireshark, it’s bare. It has a Command Line Interface (CLI), a sharp departure from the usual graphical look. 

Tcpdump is primarily utilized for traditional, system-based interfaces and only provides a simple traffic analysis. As a result, it works best to investigate issues like spikes in DNS queries.

For reference, an unusual rise in DNS queries could be a DNS flood or Distributed Denial of Service (DDoS). This attack renders a network resource unavailable, preventing users from accessing it. DDoS is highly illegal, as it has destroyed many businesses and organizations over the years.

SolarWinds Network Performance Monitor

This paid sniffer provides all the tools necessary for capturing packets. However, unlike the first two, it’s designed with more features and has been praised for its performance.

SolarWinds NPM has automated network device discovery that finds and tracks all devices in the network. It also calculates baseline thresholds and plans capacity to help forecast problems and security breaches in the future.

The tool has hardware health monitoring features that measure temperature, power supply, and fan speed. In addition, it sends warnings via email or SMS should any monitors see abnormal activity. 

ColaSoft Capsa

ColaSoft Capsa is a shareware that offers two versions. Capsa Free is a special edition for students and computer enthusiasts to learn about networking technology. In contrast, Capsa Network Analyzer is a professional suite for enterprises or large organizations.

Capsa, the paid version, has a lot of advanced features. These include a Voice over Internet Protocol (VoIP) analysis module for VoIP-based applications and a task scheduler that automates packet captures.

Kismet

This tool is a freemium software that’s supported by OSX, Linux, and sometimes Windows 10 under the WSL framework. It works with Wi-Fi or Bluetooth interfaces and other capture hardware. And, on Windows, it runs on remote captures. 

Like Wireshark, Kismet has a graphical interface. It's also free and open-sourced, but only partially. Kismet offers a paid premium version with consulting and additional services for a better user experience.

Advantages and Disadvantages of PCAP

PCAP is an asset to admins and cybersecurity teams. Still, it’s not the only network monitoring solution available. There are plenty of other systems that offer the same thing. 

However, if you plan on integrating regular packet capturing into your infrastructure, there are some benefits and drawbacks.

These pros and cons include: 

Advantages

• Complete Traffic Overview. Packet capturing gives you an overall picture of a network. They contain a significant level of detail. This allows you to monitor what goes in and out more closely than other solutions. 
• Hardware Agnostic. PCAP doesn’t need support from specialized hardware of any kind. You can even do it using any device connected to a network, but it has to have the capacity to run PCAP files.
• Further Analysis-Ready Data. PCAP files can be stored for future analysis. As a result, other network analysts can bring them up and investigate them. 

Disadvantages

• Fixed Fields. There isn’t much room for modifying anything because packet capturing copies an existing IP packet.
• Big Data Sizes. PCAP requires a lot of storage, making it ideal for higher-end devices. A file can occupy gigabytes of space even if filtering has been applied. Consequently, if a device can’t process a PCAP file, it will significantly slow down.
• Information Overload. Because packet capturing leaves no stone unturned, the data captured is too voluminous. Often, a massive chunk of it is unnecessary. Gobs of extra data bury the critical information needed for analysis.

PCAP offers many benefits, but it is also essential to understand its disadvantages. This way, you can use it to its full potential. 

Wrap Up

Overall, PCAP's benefits can significantly improve an enterprise’s infrastructure. Packet Capturing is a valuable process that maintains a network. It provides analysts with useful data for monitoring, troubleshooting, and tightening security. 

However, PCAP is not a network solution for newbies or anyone with low-performing devices. The vast data converted into PCAP files requires significant computing power to access and a long time to interpret.

PCAP works best if you know what you’re doing and what you’re using. However, if you’re new to network administration, you should explore more beginner-friendly options.