I am trying to capture traffic to 127.0.0.1 on a Windows 10 computer with Wireshark. I have installed NPCap but it does not appear to be capturing that tr5affic.
Looking at the interface options in Wireshark for the loopback adapter I see it has IPV4 address of 0.0.0.0. Is this correct and if so, how do I capture the localhost traffic.
Thanks,
Sid
It seems the way to capture localhost traffic for use with Wireshark is to use "RawCap" and then examine the captured data in WireShark.
RawCap.exe may be downloaded from here -> http://www.netresec.com/?page=RawCap
Sid
Wireshark used to be installed with Winpcap behind the scenes, but Winpcap, to my knowledge, never supported packet capture over localhost. And of course, Winpcap has not been updated since 2013 IIRC.
Npcap, which is the supported replacement for Winpcap, does support localhost packet capture. And since Wireshark now delivers Npcap instead of Winpcap, it is capable of capturing and displaying packets captured on localhost.
To use the functionality, open Wireshark. At the bottom of the opening screen, there should be an "Adapter for loopback traffic capture." Double-click that, and you're off!
Two quick points.
I'm using Wireshark v3.2.7.
Packets captured off the loopback adapter do not start with an Ethernet frame, for example. They start with what Wireshark calls a Null/Loopback header. It is a 4-byte header that typically has a value of 2 in big-endian order. Read more here.
HTH
Related
Could anyone please tell how NBNS packets are getting generated in Wireshark once we start the live capturing for a particular interface. My objective is to get the hostname of the different machines through PCAP passively. I wanted to know how the packet is getting generated in Wireshark.
You can control it easily.
Click on “Edit”
Click on “Preferences”
You can enable/disable Name Resolution options as per your requirement.
I happened to find a method for generating the NBNS traffic. By default, the NetBIOS feature is already enabled in all windows machines. An NBNS packet is captured in Wireshark when any windows machines get connected to a particular interface (eg: WiFi) after the sniffing for that particular interface starts.A broadcast NBNS packet will be sent across all machines connected to the network. Through this NBNS packet, you can get the MAC address and mainly the hostname/device name of that particular IP.
PS: Wireshark won't be able to generate NBNS packets for devices that are already connected prior to the sniffing.
I'm new to the networking world and I'm using Wireshark to learn stuffs about the network.
I was hanging around in Wireshark while I was using my VPN for circumventing the internet filter (living in a dictatorship country).
While I was using the VPN I see packets that their source or destination IP was neither my IP nor VPN server IP.
I considered two things about my problem:
1- I know my VPN uses its VPN server to send my whole packets to that server then forward them to my deserved destination, then take the response and send it to my client (is that correct?).
2- In Wireshark, I just can see the packets that their either source or destination address is my IP address.
My packets before using VPN:
As you can see, their either source or destination IP is my IP (192.168.1.101).
After using VPN, VPN:
Wireshark:
I tried filtering packets with my IP like this ip.addr == 192.168.1.101 to see only the packets that their either source or destination IP was my private IP, and guess what? nothing was changed. Why did this happen? Wasn't that supposed to filter my packets?
I also checked those packets' MAC and compared them with my MAC, and they were identical.
So my main question is why these kinds of wandering packets were showed by Wireshark? Is my VPN client insecure and trying to sending my data to other places? Or I'm wrong about how my VPN works?
Also, I appreciate it If somebody tells me more explanation about how my VPN or Wireshark works so that I have these types of packets in my Wireshark.
First of all your considerations, point no.1 is right, that's how a typical VPN works and point no.2 is wrong.
Wireshark can capture any packet (any source IP or destination IP) flowing in and out of a network adapter technically known as NIC card. NIC cards are the way through which you can connect to a network (Internet). A quick brief of NIC over here
A typical VPN client software would form a virtual NIC to encrypt and send your traffic through it. A quick brief of VPNs over here
So, to see the required traffic in Wireshark, you must capture traffic from an appropriate interface (NIC card). The answer over here might be helpful.
I am using a mac and trying to capture packets live packets when I am loading up a website. I am connected over Wifi and am able to capture packets without those filters being used.
However when I enter in 'tcp port http' I am coming up empty handed.
Any suggestions to solve this?
When you use a port name in a capture filter expression, libpcap (the packet capture library that Wireshark uses) needs to convert the name into a number that it can use to match against bytes the captured packet. It does so by looking up the port name in /etc/services. (Specifically, it calls getaddrinfo, which usually looks up the port in /etc/services on macOS and Linux, and C:\system32\drivers\etc\services on Windows.) If I open /etc/services on my system here, "http" corresponds to port 80.
However, the modern web doesn't really use port 80 any more. Most web traffic these days is encrypted using HTTPS, and the IANA-assigned port for HTTPS is 443.
You might have better luck using "tcp port 443" or "tcp port 443 or tcp port 80" to make sure you capture both HTTP and HTTPS.
As far as I know, the filter has to be tcp.port == 80.
But if your Wireshark doesn't capture anything (without filter), you may check your installation and the wiki.
Running on a Linux system, getting UDP packets from another computer address to let's say 192.168.0.2 from another address let's say 192.168.166.66, I can see the UDP packets coming in with tcpdump. However, if I use netcat I don't actually receive the packets.
If I create an interface on 192.168.166.XXX network, then netcat is able to receive the packets no problem.
What basic networking concept am I missing? Why do I need to have an interface on the network of the sending IP when I can see with tcpdump that they are being delivered correctly?
tcpdump per default puts the interface into promiscious mode, which lets you see all the packets arriving at your network interface. But, your operating system only processes packets destined for the local system, e.g. either having the local or a broadcast address as destination.
The final solution to this problem was to disable Reverse Path Forwarding (RPF) on the interface. There are security implications here, but after careful review this was the correct path forward in this particular case.
RPF was turned off by modifying /etc/sysctl.conf:
net.ipv4.conf.eth0.rp_filter=0
Some more information on RPF:
Wikipedia - Reverse path forwarding
Linux kernel rp_filter settings
Can any data exchanged on a local machine using the loopback IP 127.0.0.1 (localhost) be packet sniffed if the PC is also connected to a network (wireless or landline)?
Would like to know if the loopback, as a means of interprocess communication for locally running processes, can be regarded as a secure means of exchanging data (i.e., not privy to ease-dropping by anyone that resides externally on the network with a packet sniffer program).
This question is being asked in respect to all the pertinent OS platforms:
Win2K/WinXP
Vista
Windows 7
Mac OS X
Linux
Yes, this is secure.
As VBNight stated, the traffic never hits the wire or air.
But, you can actually sniff localhost traffic on your local machine. For example on my linux box I did the following:
sudo tcpdump -i lo
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on lo, link-type EN10MB (Ethernet), capture size 96 bytes
15:29:58.056585 IP localhost.56010 > localhost.16001: S 3572335637:3572335637(0) win 32792 <mss 16396,sackOK,timestamp 132126218 0,nop,wscale 6>
15:29:58.056604 IP localhost.16001 > localhost.56010: R 0:0(0) ack 3572335638 win 0
15:29:59.026016 IP localhost.41664 > localhost.41664: UDP, length 1
15:29:59.026346 IP localhost.41664 > localhost.41664: UDP, length 1
15:29:59.126838 IP localhost.41664 > localhost.41664: UDP, length 1
15:29:59.127486 IP localhost.41664 > localhost.41664: UDP, length 1
So, you can use it to sniff your own traffic/IPC messages, but nobody else can see it on the network.
This is a very common case in systems to use a protocol like TCP or UDP for local IPC over the lo interface.
It should be safe from packet sniffing off the network because the traffic never goes on the wire (or airwaves).
A process on that local machine could sniff the packets tho.
You can use RawCap (a raw socket sniffer) to sniff localhost traffic in Windows. RawCap will create a pcap file that you can load into Wireshark, NetworkMiner or whatever you'd like.
You'll find more info on this StackOverflow thread:
Sniffer for localhost (Windows OS)
I'm pretty sure that popular packet sniffers can't sniff the loopback interface (a cause of much grief and annoyance when debugging stuff on localhost).
The loopback interface can be regarded as secure with respect to the external network. It isn't secure within the same host.
The answers so far are correct, but I will phrase it a different way. It is possible to sniff the loopback adapter communications on the localhost itself, but it usually requires special drivers depending on the operating system. Loopback communications is safe from external sniffers though.
I have had cases where I needed to sniff loopback communications and it was not easy to setup, but it was possible (at least on Windows and I would bet so with Linux as well).