Ubuntu Manpage: scapy - Interactive packet manipulation tool

name
synopsis
description
options
commands
files
examples
see also
bugs
author

NAME

       scapy - Interactive packet manipulation tool

SYNOPSIS

       scapy [options]

DESCRIPTION

This manual page documents briefly the scapy tool.

scapy is a powerful interactive packet manipulation tool, packet generator, network scanner, network
discovery, packet sniffer, etc. It can for the moment replace hping, parts of nmap, arpspoof, arp-sk,
arping, tcpdump, tshark, p0f, ...

scapy uses the python interpreter as a command board. That means that you can use directly python
language (assign variables, use loops, define functions, etc.) If you give a file as parameter when you
run scapy, your session (variables, functions, intances, ...) will be saved when you leave the
interpretor, and restored the next time you launch scapy.

The idea is simple. Those kind of tools do two things : sending packets and receiving answers. That's
what scapy does : you define a set of packets, it sends them, receives answers, matches requests with
answers and returns a list of packet couples (request, answer) and a list of unmatched packets. This has
the big advantage over tools like nmap or hping that an answer is not reduced to (open/closed/filtered),
but is the whole packet.

On top of this can be build more high level functions, for example one that does traceroutes and give as
a result only the start TTL of the request and the source IP of the answer. One that pings a whole
network and gives the list of machines answering. One that does a portscan and returns a LaTeX report.

OPTIONS

       Options for scapy are:

       -h     display usage

       -d     increase log verbosity. Can be used many times.

       -s FILE
              use FILE to save/load session values (variables, functions, intances, ...)

       -p PRESTART_FILE
              use PRESTART_FILE instead of $HOME/.scapy_prestart.py as pre-startup file

       -P     do not run prestart file

       -c STARTUP_FILE
              use STARTUP_FILE instead of $HOME/.scapy_startup.py as startup file

       -C     do not run startup file

COMMANDS

       Only the vital commands to begin are listed here for the moment.

       ls()   lists supported protocol layers. If a protocol layer is given as parameter, lists its  fields  and
              types of fields.

       lsc()  lists some user commands. If a command is given as parameter, its documentation is displayed.

       conf   this object contains the configuration.

FILES

       $HOME/.scapy_prestart.py  This  file is run before scapy core is loaded. Only the is available. This file
       can be used to manipulate conf.load_layers list to choose which layers will be loaded:

       conf.load_layers.remove("bluetooth")
       conf.load_layers.append("new_layer")

       $HOME/.scapy_startup.py This file is run after scapy is loaded. It can be used to configure some  of  the
       scapy behaviors:

       conf.prog.pdfreader="xpdf"
       split_layers(UDP,DNS)

EXAMPLES

       More  verbose examples are available at http://www.secdev.org/projects/scapy/demo.html Just run scapy and
       try the following commands in the interpreter.

       Test the robustness of a network stack with invalid packets:
       sr(IP(dst="172.16.1.1", ihl=2, options="b$2$", version=3)/ICMP())

       Packet sniffing and dissection (with a bpf filter or thetereal-like output):
       a=sniff(filter="tcp port 110")
       a=sniff(prn = lambda x: x.display)

       Sniffed packet reemission:
       a=sniff(filter="tcp port 110")
       sendp(a)

       Pcap file packet reemission:
       sendp(rdpcap("file.cap"))

       Manual TCP traceroute:
       sr(IP(dst="www.google.com", ttl=(1,30))/TCP(seq=RandInt(), sport=RandShort(), dport=dport)

       Protocol scan:
       sr(IP(dst="172.16.1.28", proto=(1,254)))

       ARP ping:
       srp(Ether(dst="ff:ff:ff:ff:ff:ff")/ARP(pdst="172.16.1.1/24"))

       ACK scan:
       sr(IP(dst="172.16.1.28")/TCP(dport=(1,1024), flags="A"))

       Passive OS fingerprinting:
       sniff(prn=prnp0f)

       Active OS fingerprinting:
       nmap_fp("172.16.1.232")

       ARP cache poisonning:
       sendp(Ether(dst=tmac)/ARP(op="who-has", psrc=victim, pdst=target))

       Reporting:
       report_ports("192.168.2.34", (20,30))

BUGS

       Does not give the right source IP for routes that use interface aliases.

       May miss packets under heavy load.

       Session saving is limited by Python ability to marshal objects. As a consequence,  lambda  functions  and
       generators can't be saved, which seriously reduce usefulness of this feature.

       BPF filters don't work on Point-to-point interfaces.

AUTHOR

       Philippe Biondi <phil@secdev.org>

       This manual page was written by Alberto Gonzalez Iniesta <agi@agi.as> and Philippe Biondi.

                                                  May 12, 2003                                          SCAPY(1)