impacket-sniffer

View documentation for the original command

$ tldr sniffer.py

impacket-sniffer.py [-h] [-i interface] [-p port] [-r pcap_file] [-w output_file] [-v level]

-h
    Shows the help message and exits.

-i interface
    Specifies the network interface to sniff on (e.g., eth0, wlan0). If not specified, it may try to listen on all available interfaces or require a specific one depending on the environment.

-p port
    Filters traffic by a specific destination or source port number.

-r pcap_file
    Reads packets from a Wireshark/tcpdump PCAP file instead of performing live capture.

-w output_file
    Writes captured raw packets to a PCAP file.

-v level
    Sets the verbosity level for output (e.g., 0 for minimal, 1 for normal, 2 for verbose dissection of protocol details).

impacket-sniffer is a network sniffing tool provided by the Impacket library, a collection of Python classes for working with network protocols. Unlike generic sniffers like tcpdump, impacket-sniffer specializes in parsing and displaying details of various Windows-centric network protocols such as SMB, MSRPC, DCE/RPC, and NTLM authentication.

It's widely used by security professionals, penetration testers, and researchers to analyze network traffic for vulnerabilities, credential capture, or to understand protocol interactions. It can capture live traffic or read from PCAP files, offering different levels of verbosity for protocol dissection, making it an invaluable tool for analyzing complex Windows network communication.

Caveats and Limitations:
1. Requires root privileges for live packet capture on most Linux systems.
2. Requires the Impacket Python library and its dependencies to be installed.
3. Primarily focused on parsing Windows-specific protocols (SMB, MSRPC, NTLM), so its generic packet dissection capabilities are less comprehensive than tools like Wireshark or tcpdump.
4. Output can be very verbose, especially with higher verbosity levels, which might be overwhelming for quick analysis.

impacket-sniffer is a Python script and part of a larger Python library. This allows for easy extensibility, integration into other Python security tools, and cross-platform compatibility where Python is supported.

Unlike general-purpose sniffers, its strength lies in its deep understanding and dissection capabilities for complex Windows authentication and communication protocols, making it a go-to tool for analyzing Active Directory and Windows network interactions.

Impacket is a Python library developed by SecureAuth (formerly Core Security) primarily for working with network protocols. It emerged as a powerful tool for low-level programmatic access to network protocols, particularly those common in Windows environments.

impacket-sniffer is one of the many examples/scripts built on top of the Impacket library, showcasing its capabilities in network traffic analysis. Its development has focused on providing robust implementations of protocols like SMB, DCE/RPC, LDAP, and NTLM, making it invaluable for security research, red teaming, and penetration testing.

tcpdump(1), wireshark(1), tshark(1), ettercap(8)