Ubuntu Manpage: scapy - Interactive packet manipulation tool

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)