What is Wireshark?

  What is Wireshark?

Wireshark is the most common network protocol analyzer. In addition to being a free and an open source packet following the terms of the GNU General Public License(GPL), we mainly use it when it comes to network troubleshooting, analysis, software and communications protocol development, and education. It shows its user what is happening on their network at a microscopic level. A majority of commercial and non-profit organizations, government agencies, and educational institutions use Wireshark.

History:

In 1998 Gerald Combs, a computer science graduate of the University of Missouri-Kansas City, started a project and named it Ethereal. It was the basic foundation of Wireshark. having this name since 2006 when Combs started to work with CACE Technologies while holding the copyright of most of the project’s code. The rest of the code was opened for any modification under the GPL Terms. Then, volunteer contributions of network experts around the universe added to the project, making it as famous and widely used as it is nowadays.

Because Combs did not own the Ethereal trademark he decided to change its name into Wireshark. It was not until 2010 when Riverbed Technology purchased CACE Technologies to become the main sponsor of Wireshark. There are several contributors –around 600 authors– to this product; still, Combs is the essential responsible for maintaining the overall code and executing new version releases of Wireshark.

Wireshark won several awards for its vital role in today’s network security. It got an award for the Most Important Open-Source App of All-Time by eWeek. Moreover, it won the Editor’s Choice award from PC Magazine. In addition, Insecure.Org network security tools survey ranked as a top packet sniffer.

The functionality of Wireshark:

Similar to tcpdump, a common packet analyzer, Wireshark allows us to analyze network packets but with the aid of a graphical front-end and some extra integrated sorting and filtering options. A Network Interface Controller(NIC) is put into this mode if it does support promiscuous mode. This is usually in order to visualize all the traffic on the interface not merely the interface’s configured addresses and broadcast/multitask traffic.

However, to get the entire network traffic, other techniques such as port mirroring and network taps are utilized. This is done along with using the promiscuous mode on a port. This is attributed to the fact that a port does not necessarily get all the network traffic.

Wireshark 1.4 and later has the ability to put wireless network interface controllers into monitor mode. If some packets are captured by a remote machine and sent to Wireshark, protocols of type TZSP or OmniPeek’s protocol – where OmniPeek is another packet analyzer- are analyzed at the time they were captured on their remote machines.

What features does Wireshark include?

In fact, Wireshark offers a large set of features. In the following points, I will attempt to summarize the features that

Wireshark offers:

  • Wireshark is a network analyzer that inspects Hundreds of protocols.
  • It allows both offline analysis and live captures.
  • It could run on diverse operating systems such as Microsoft Windows, Linux, macOS, Sun Solaris, and several other platforms.
  • A graphical user interface (GUI) is supported using QT widget toolkit, which enables us to browse captured network data, or in the non-GUI version, TTY-mode TShark utility could be utilized for the same purpose as well.
  • It offers sufficient Voice over Internet Protocol(VoIP) analysis. We can even play the media flow when decoding such captured traffic.
  • Wireshark uses pcap to capture packets.
  • It generates Capture files in gzip format, which is easily decompressed.
  • Such captured files could be programmatically edited or altered to the “editcap” programming with the help of some command-line switches.
  • It allows the traffic capturing of Raw Universal Serial Bus(USB).
  • Wireshark is able to capture packets from ns OPNET Modeler, NetSim, and some other network simulation tools.
  • It supports Read/Write of many capture file formats such as tcpdump (libpcap) which is the native network trace file format, Pcap NG, Catapult DCT2000, Cisco Secure IDS iplog, Microsoft Network Monitor, Network General Sniffer, Sniffer Pro, NetXray, Network Instruments Observer, NetScreen snoop, Novell LANalyzer, RADCOM WAN/LAN Analyzer, Shomiti/Finisar Surveyor, Tektronix k12xx, Visual Networks Visual UpTime, WildPacketsEtherPeek/TokenPeek/AiroPeek and several other formats.
  • It reads Live Data through different means such as Ethernet IEEE 802.11, PPP/HDLC, ATM, loopback, Bluetooth, FDDI, and many others.
  • The decryption is supported for many protocols including IPsec, ISAKMP, Kerberos, SNMPv3, SSL/TLS, WEP, and WPA/WPA2.
  • Application of Coloring rules to the packet list allows for quick and easy analysis. See section Color Coding for further details.
  • One can ensure that only the triggered traffic becomes analyzed by applying particular filters, timers, and other settings.
  • XML, PostScript, CSV or plain text are all the types that output is exported and formatted.

Security Policies:

In general, there is no need for certain security privileges to allow us to utilize neither Wireshark or TShark. Nowadays, only requires to have tcpdump or dumpcap, given special privileges, and run on a machine to capture traffic with no need for any further privileges for the user.

But how can a superuser grant the aforementioned required privileges to a user? The answer basically lies in the fact that tcpdump or dumpcap which come with Wireshark should have special privileges for them to capture packets into a file. This file would require the opening of Wireshark for analysis with seriously restricted privileges. Even wireless networks could harness Aircrack wireless security tools and capture IEEE 802.11 frames to further read the resulting tcpdump dumpcap files with running Wireshark afterward.

Why do we need to restrict the users from privileges to freely run Wireshark and use its tools? This is basically because capturing traffic calls an enormous number of protocol dissectors, which could most probably arise a network security risk. Since there is a potential of finding a bug in one of these dissectors and thereby exploiting it, this puts the entire security system at a great risk. That is why running Ethereal/Wireshark in the past required superuser privileges for one to be responsible for what can potentially be affected.

Filtering Packets:

Sometimes we need to capture specific traffic packets such as traffic which a program sends when phoning home. While a large number of captured packets in a network, one has to close down all other applications using the network in order to get some specific traffic type. At this point emerges the importance of Wireshark’s filters. At the top of the window, there is a filter box at which we can simply type a certain filter name in order to apply this filter and then we should click Apply, or press Enter alternatively. For instance, to see only DNS packets, we type “DNS” in the filter box. Wireshark helps auto-complete a filter name while writing its name in the filter box.

Color Coding:

The colors Green, Blue, and Black distinguish the type of captured packets. Conventionally, green color indicates Transmission Control Protocol (TCP) traffic. Dark blue, on the other hand, is Name System (DNS) traffic, whereas light blue demonstrates User Datagram Protocol (UDP) traffic. Black shows TCP packets with problems such as being out-of-order.

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References:

https://en.wikipedia.org/wiki/Wireshark

https://www.howtogeek.com/104278/how-to-use-wireshark-to-capture-filter-and-inspect-packets/amp/

https://www.wireshark.org/

https://wiki.wireshark.org/

http://sectools.org/

https://www.quora.com/unanswered/What-security-policies-can-you-check-using-Wireshark

Elsewhere, check out my other post about Metaspoilt.

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This post was written by hsamanoudy

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