i want to filter some headers in a wireshark capture (converted to text format) so i can analyse these set of headers.i need a python script to do this. any help would be appreciated
You might want to look at dpkt. It's a Python library to simplify reading (or generating) network data. Just save your Wireshark data as a Pcap stream and it can easily be opened from within Python.
I don't know exactly which headers you want or how you need them filtered and formatted, but here's an example of what you could write: (taken from a contributor's blog post)
import dpkt
pcap = dpkt.pcap.Reader(open('test.pcap'))
for timestamp, buf in pcap:
eth = dpkt.ethernet.Ethernet(buf)
ip = eth.data
tcp = ip.data
print 'Got data from port ' + str(tcp.port)
Related
I am trying to write a python program to parse packet capture using dpkt module. I have used it on packet captures that had Ethernet and tcpdump captures and it worked fine. However, my current packet capture is raw packet capture that directly has IP header and subsequent protocols and it seems like dpkt is not able to understand these captures. Picture of capture file is attached. enter image description here
The code I had was
f = open(ipfile, 'rb')
pcap = dpkt.pcap.Reader(f)
for ts,buf in pcap:
eth = dpkt.ethernet.Ethernet(buf) //Also tried with eth = dpkt.sll.SLL(buf), but no luck.
ip = eth.data
tcp = ip.data
Any ideas on how to parse such captures?
Thanks !!
I had the same issue with CAIDA pcap. Try
ip = dpkt.ethernet.Ethernet(buf)
I am able to read .pcap file with pyshark. Here is my code:
packets = pyshark.FileCapture(pcap_dir) # pcap_dir is the directory of my pcap file
To print a packet, I use print(packets[0]). My question is: how can I convert packets[0] to its binary value? For example, this can be useful if I want to send the packet again to the network
I was able to solve the problem. I simply used:
packets = pyshark.FileCapture(
input_file=pcap_dir,
use_json=True,
include_raw=True
)._packets_from_tshark_sync() # pcap_dir is the directory of my pcap file
hex_packet = packets.__next__().frame_raw.value
print(hex_packet)
binary_packet = bytearray.fromhex(hex_packet)
print(binary_packet)
Also, it might be useful to check this
To start off, I have read through other raw answers pertaining to scapy on here, however none have been useful, maybe I am just doing something wrong and thats what has brought me here today.
So, for starters, I have a pcap file, which started corrupted with some retransmissions, to my belief I have gotten it back to gether correctly.
It contains Radiotap header, IEEE 802.11 (dot11), logical-link control, IPv4, UDP, and DNS.
To my understanding, the udp packets being transmitted hold this raw data, however, do to a some recent quirks, maybe the raw is in Radiotap/raw.
Using scapy, I'm iterating through the packets, and when a packet with the Raw layer is found, I am using the .show() function of scapy to view it.
As such, I can see that there is a raw load available
###[ Raw ]###
\load \
|###[ Raw ]###
| load = '#\x00\x00\x00\xff\xff\xff\xff\xff\xff\x10h?'
So, I suppose my question is, how can I capture this payload to receive whatever this may be, To my knowledge the load is supposed to be an image file, however I have trouble believing such, so I assume I have misstepped somewhere.
Here is the code I'm using to achieve the above result
from scapy.all import *
from scapy.utils import *
pack = rdpcap('/home/username/Downloads/new.pcap')
for packet in pack:
if packet.getlayer(Raw):
print '[+] Found Raw' + '\n'
l = packet.getlayer(Raw)
rawr = Raw(l)
rawr.show()
Any help, or insight for further reading would be appreciated, I am new to scapy and no expert in packet dissection.
*Side note, previously I had tried (using separate code and server) to replay the packets and send them to myself, to no avail. However I feel thats due to my lack of knowledge in receipt of UDP packets.
UPDATES - I have now tested my pcap file with a scapy reassembler, and I've confirmed I have no fragmented packets, or anything of the sort, so I assume all should go smoothly...
Upon opening my pcap in wireshark, I can see that there are retransmissions, but I'm not sure how much that will affect my goals since no fragmentation occurred?
Also, I have tried the getlayer(Raw).load, if I use print on it I get some gibberish to the screen, I'm assuming its the data to my would-be-image, however I need to now get it into a usable format.
You can do:
data = packet[Raw].load
You should be able to access the field in this way:
l = packet.getlayer(Raw).load
Using Scapy’s interactive shell I was successful doing this:
pcap = rdpcap('sniffed_packets.pcap')
s = pcap.sessions()
for key, value in s.iteritems():
# Looking for telnet sessions
if ':23' in key:
for v in value:
try:
v.getlayer(Raw).load
except AttributeError:
pass
If you are trying to get the load part of the packet only, you can try :
def handle_pkt(pkt):
if TCP in pkt and pkt[TCP].dport == 5201:
#print("got a packet")
print(pkt[IP])
load_part = pkt[IP].load
print("Load#",load_part)
pkt.show2()
sys.stdout.flush()
I'm actually trying to sniff packets with python (using pypcap and dpkt).
I tried the following :
import dpkt, pcap
pc = pcap.pcap() # construct pcap object
pc.setfilter('src host X.X.X.X or dst host X.X.X.X')
for timestamp, packet in pc:
print dpkt.ethernet.Ethernet(packet)
But nothing happens when I launch the script... Did I miss something ?
Using Python 2.7
On OS X Yosemite (10.10)
The question is old but for new people who might hit this. The github 'chains' project uses both pypcap and dpkt for exactly this kind of thing (Disclaimer: I'm involved with all three projects :) https://github.com/SuperCowPowers/chains
chains/sources/packet_streamer.py (code showing use of pypcap for 'sniffing')
chains/links/packet_meta.py (code showing use of dpkt for packet parsing)
For those that just want to use pypcap/dpkt here's a working code snippet:
import pcap
import dpkt
sniffer = pcap.pcap(name=None, promisc=True, immediate=True)
for timestamp, raw_buf in sniffer:
output = {}
# Unpack the Ethernet frame (mac src/dst, ethertype)
eth = dpkt.ethernet.Ethernet(raw_buf)
output['eth'] = {'src': eth.src, 'dst': eth.dst, 'type':eth.type}
# It this an IP packet?
if not isinstance(eth.data, dpkt.ip.IP):
print 'Non IP Packet type not supported %s\n' % eth.data.__class__.__name__
continue
# Grab ip packet
packet = eth.data
# Pull out fragment information
df = bool(packet.off & dpkt.ip.IP_DF)
mf = bool(packet.off & dpkt.ip.IP_MF)
offset = packet.off & dpkt.ip.IP_OFFMASK
# Pulling out src, dst, length, fragment info, TTL, checksum and Protocol
output['ip'] = {'src':packet.src, 'dst':packet.dst, 'p': packet.p,
'len':packet.len, 'ttl':packet.ttl,
'df':df, 'mf': mf, 'offset': offset,
'checksum': packet.sum}
print output
You should check out Scapy. Its a powerful networking tool, that can be used interactivly as well. Its written in python, hence you can use it in your scripts as well.
In scapy its as easy as (but you can easily add filters as well):
sniff(iface='eth0')
If you didn't place the path to a file in pcap.pcap(), there's no pcap for it to parse.
I ran your script with a glob of from a pcap directory I have and replaced the IP with one in my network, seemed like it worked.
You sure you installed pypcap and dpkt?
Here's exactly what I did with your script.
import dpkt, pcap, glob
for i in glob.glob("/pcap/*.pcap"):
pc = pcap.pcap(i)
pc.setfilter('src host 192.168.1.140 or dst host 192.168.1.140')
for timestamp, packet in pc:
print dpkt.ethernet.Ethernet(packet)
It printed a lot of stuff.
Nothing jumps out at the code, so I'm wondering if it is just the network.
Can you double check the IP addresses and also maybe run tcpdump as a sanity check to make sure you can see traffic?
For tcpdump something like this
$ sudo tcpdump -i en1 "src host 10.0.0.2 or dst host 10.0.0.2"
I have a file which contains raw IP packets in binary form. The data in the file contains a full IP header, TCP\UDP header, and data. I would like to use any language (preferably python) to read this file and dump the data onto the line.
In Linux I know you can write to some devices directly (echo "DATA" > /dev/device_handle). Would using python to do an open on /dev/eth1 achieve the same effect (i.e. could I do echo "DATA" > /dev/eth1)
Something like:
#!/usr/bin/env python
import socket
s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW)
s.bind(("ethX", 0))
blocksize = 100;
with open('filename.txt') as fh:
while True:
block = fh.read(blocksize)
if block == "": break #EOF
s.send(block)
Should work, haven't tested it however.
ethX needs to be changed to your interface (e.g. eth1, eth2, wlan1, etc.)
You may want to play around with blocksize. 100 bytes at a time should be fine, you may consider going up but I'd stay below the 1500 byte Ethernet PDU.
It's possible you'll need root/sudoer permissions for this. I've needed them before when reading from a raw socket, never tried simply writing to one.
This is provided that you literally have the packet (and only the packet) dumped to file. Not in any sort of encoding (e.g. hex) either. If a byte is 0x30 it should be '0' in your text file, not "0x30", "30" or anything like that. If this is not the case you'll need to replace the while loop with some processing, but the send is still the same.
Since I just read that you're trying to send IP packets -- In this case, it's also likely that you need to build the entire packet at once, and then push that to the socket. The simple while loop won't be sufficient.
No; there is no /dev/eth1 device node -- network devices are in a different namespace from character/block devices like terminals and hard drives. You must create an AF_PACKET socket to send raw IP packets.