PyShark: Python Packet Parsing with Wireshark

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In the world of network programming and analysis, efficient packet parsing is essential. Python offers various libraries for this purpose, and PyShark stands out as a unique option. This article explores PyShark, a Python wrapper for tshark, Wireshark’s command-line utility. PyShark enables Python developers to parse packets using Wireshark dissectors, providing a powerful tool for network analysis.

What Is PyShark?

PyShark is a Python utility and library designed to parse packets using Wireshark dissectors. Unlike some other packet parsing modules, PyShark doesn’t directly parse packets; instead, it leverages tshark’s ability to export XMLs and uses them for parsing. This approach allows PyShark to use all installed Wireshark dissectors, making it a versatile choice for network analysis.

Installation

Before diving into PyShark, you need to install it. PyShark supports Python 3.7 and higher. You can install it using pip with the following command:

pip install pyshark

Alternatively, you can clone the PyShark repository from GitHub and install it manually:

git clone https://github.com/KimiNewt/pyshark.gitcd pyshark/srcpython setup.py install

Usage

Reading from a Capture File

One common use case for PyShark is parsing packets from a capture file. Here’s how you can do it:

import pyshark
cap = pyshark.FileCapture(‘/path/to/your/capture_file.cap’)for packet in cap: print(packet)

Reading from a Live Interface

PyShark can also capture packets from a live network interface. Here’s an example:

capture = pyshark.LiveCapture(interface=’eth0′)capture.sniff(timeout=50)
for packet in capture: print(‘Just arrived:’, packet)

Filtering Packets

PyShark allows you to filter packets, either when reading from a capture file or a live interface. You can use BPF (Berkeley Packet Filter) filters or display filters to narrow down the packets you’re interested in. Here’s an example using a display filter:

filtered_cap = pyshark.FileCapture(‘/path/to/your/capture_file.cap’, display_filter=’http’)for packet in filtered_cap: print(packet)

Accessing Packet Data

Accessing packet data is straightforward with PyShark. Packets are divided into layers, and you can access their attributes. For instance:

packet[‘ip’].dst # By protocol stringpacket.ip.src # By protocol attributepacket[2].src # By layer index

You can also use the dir(packet.my_layer) command to see available attributes for a layer.

Decrypting Packet Captures

PyShark supports automatic decryption of traces using standards like WEP, WPA-PWD, and WPA-PSK. For example:

capture = pyshark.FileCapture(‘/path/to/your/encrypted_capture.cap’, decryption_key=’your_decryption_key’)for packet in capture: print(packet)

Comparison Table

Feature	PyShark	Scapy	dpkt
Parsing from Capture	Supported	Supported	Supported
Parsing from Live	Supported	Supported	Supported
Installation	Easy (pip install pyshark)	Easy (pip install scapy)	Easy (pip install dpkt)
Protocol Support	Wireshark Dissectors	Custom Parsing and Crafting	Custom Parsing
Filtering Capabilities	Display Filters and BPF Filters	Custom Filters and Conditions	Custom Filters and Conditions
Decryption Support	WEP, WPA-PWD, WPA-PSK	Not Built-in	Not Built-in
Layer-Based Parsing	Yes	Yes	Yes
Active Development	Yes	Yes	Limited
Compatibility	Cross-platform	Cross-platform	Cross-platform

Here’s a comparative table outlining key features of PyShark, Scapy, and dpkt for packet parsing and analysis in Python. Each library has its strengths and use cases, so choosing the right one depends on your specific needs and preferences.

Video Explanation

In order to explain this topic in more detail we have prepared a special video for you. Enjoy watching it!

Key Advantages of PyShark

User-Friendly: PyShark offers a straightforward and user-friendly interface for parsing and analyzing network packets, making it suitable for both beginners and experienced developers;
Wireshark Integration: PyShark leverages the power of Wireshark dissectors, allowing you to access detailed information about various network protocols effortlessly;
Cross-Platform: It works seamlessly on both Windows and Linux operating systems, providing flexibility in your choice of development environment;
Decryption Support: PyShark supports automatic decryption of traces using encryption standards such as WEP, WPA-PWD, and WPA-PSK;
Active Development: The library is actively maintained, ensuring that it stays up-to-date with the latest developments in network protocols and technologies;
Layer-Based Parsing: You can access packet data at different layers, simplifying the process of extracting information from complex network traffic;
Filtering Capabilities: PyShark supports both display filters and BPF filters, enabling you to focus on specific packet subsets for in-depth analysis;
Versatile Usage: Whether you’re reading from a capture file, a live interface, or a remote interface, PyShark provides the necessary tools to handle various scenarios;
Protocol Support: It covers a wide range of protocols thanks to Wireshark’s extensive dissectors, making it suitable for diverse network analysis tasks;
Ease of Installation: Installing PyShark is straightforward, as it can be easily installed using the pip package manager;
Community and Documentation: PyShark benefits from an active community of users and has extensive documentation available to assist users in getting started and troubleshooting.

Conclusion

In conclusion, PyShark stands as a versatile and powerful Python library for network packet parsing and analysis. Its integration with Wireshark’s dissectors grants users access to detailed network protocol information, simplifying the often complex task of network analysis. With cross-platform compatibility, PyShark can be seamlessly employed on both Windows and Linux systems, offering flexibility to developers.

One of its standout features is its support for automatic decryption of traces using encryption standards like WEP, WPA-PWD, and WPA-PSK. This capability enhances its utility for various network security and monitoring applications.

Moreover, PyShark provides a user-friendly interface that accommodates both novice and experienced users. Its layer-based parsing approach allows for precise data extraction from network traffic, and the filtering capabilities, including display and BPF filters, enable focused analysis.

FAQ

1. What is PyShark, and how does it differ from other packet parsing libraries?

PyShark is a Python wrapper for TShark, leveraging Wireshark’s powerful dissectors to parse network packets. Unlike other packet parsing libraries, PyShark doesn’t parse packets itself; instead, it utilizes TShark’s ability to export XML data for parsing. This approach allows PyShark to provide extensive protocol support without needing to reinvent the wheel.

2. Which Python versions are supported by PyShark?

PyShark supports Python 3.7 and above. There is also a legacy version called “pyshark-legacy” available for Python 2.

3. Can PyShark capture live network traffic, and how does it work?

Yes, PyShark can capture live network traffic from a specified interface. It does this by invoking TShark with the selected interface to capture packets in real time. Users can apply display filters to focus on specific traffic.

4. How does PyShark handle packet decryption?

PyShark offers automatic decryption support for network traces using encryption standards such as WEP, WPA-PWD, and WPA-PSK. By specifying the encryption type and key, PyShark can decrypt captured encrypted traffic for analysis.