Chapter 2. Foot Printing

Definition of Foot Printing Internet foot printing

Sun Tzu on the Art of War: "If you know the enemy and know

yourself, you need not fear the result of a hundred battles.

If you know yourself but not the enemy, for every victory gained you will also suffer a defeat.

If you know neither the enemy nor yourself, you will succumb in every battle."

Definition: the gathering of information about a potential system or network (the fine art of gathering target information) a.k.a. fingerprinting

Attacker’s point of view Identify potential target systems Identify which types of attacks may be useful on target systems

Defender’s point of view Know available tools May be able to tell if system is being footprinted, be more prepared for possible attack Vulnerability analysis: know what information you’re giving away, what weaknesses you have

System (Local or Remote) IP Address, Name and Domain Operating System▪ Type (Windows, Linux, Solaris, Mac)▪ Version (98/NT/2000/2003/XP/Vista/7, Redhat, Fedora,

SuSe, Ubuntu, OS X) Usernames (and their passwords) File structure Open Ports (what services/programs are

running on the system)

Networks / Enterprises System information for all hosts Network topology▪ Gateways▪ Firewalls▪ Overall topology

Network traffic information Specialized servers▪ Web, Database, FTP, Email, etc.

Identify information you’re giving away

Identify weaknesses in systems/network

Know when systems/network is being probed

Identify source of probeDevelop awareness of threatConstruct audit trail of activity

Footprinting is necessary to systematically and methodically ensure that all pieces of information related to the aforementioned technologies are identified

Footprinting is often the most arduous task of trying to determine the security posture of an entity; however, it is one of the most important.

Footprinting must be performed accurately and in a controlled fashion

Without a sound methodology for performing this type of reconnaissance, you are likely to miss key pieces of information related to a specific technology or organization

Step 1: Determine the Scope of Your Activities determine the scope of your footprinting activities▪ Are you going to footprint the entire organization, or limit

your activities to certain subsidiaries or locations? ▪ What about business partner connections (extranets), or

disaster-recovery sites?▪ Are there other relationships or considerations?

Unfortunately, hackers have no sympathy for our struggles. They exploit our weaknesses in whatever forms they manifest themselves. You do not want hackers to know more about your security posture than you do!

Step 2: Get Proper Authorization One thing hackers can usually disregard that

you must pay particular attention to is what we techies affectionately refer to as layers eight and nine of the seven-layer OSI Model—Politics and Funding▪ Do you have authorization to proceed with your

activities?▪ what exactly are your activities? ▪ Is the authorization from the right person(s)? ▪ Is it in writing? ▪ Are the target IP addresses the right ones?

Step 3: Publicly Available Information Company web pages Related organizations Location details Phone numbers, contact names, e-mail addresses,

and personal details Current events (mergers, acquisitions, layoffs, rapid

growth, etc.) Privacy or security policies, and technical details

indicating the types of security mechanisms in place Archived information Disgruntled employees Search engines, Usenet, and resumes Other information of interest

Step 4: WHOIS & DNS Enumeration So who is "managing" the Internet today, you ask?

These core functions of the Internet are "managed" by a nonprofit organization named the Internet Corporation for Assigned Names and Numbers (ICANN; http://www.icann.org).

ICANN is a technical coordination body for the Internet. Created in October 1998 by a broad coalition of the Internet's business, technical, academic, and user communities, ICANN is assuming responsibility for a set of technical functions previously performed under U.S. government contract by the Internet Assigned Numbers Authority (IANA; http://www.iana.org) and other groups. (In practice, IANA still handles much of the day-to-day operations, but these will eventually be transitioned to ICANN.)

Specifically, ICANN coordinates the assignment of the following identifiers that must be globally unique for the Internet to function: Internet domain names IP address numbers Protocol parameters and port numbers

In addition, ICANN coordinates the stable operation of the Internet's root DNS server system.

To be thorough, we could have done the same searches via the command-line WHOIS client with the following three commands: [bash]$ whois com -h whois.iana.org [bash]$ whois keyhole.com -h whois.verisign-grs.com [bash]$ whois keyhole.com -h whois.omnis.com

There are also several websites that attempt to automate this process with varying degrees of success: http://www.allwhois.com http://www.uwhois.com http://www.internic.net/whois.html

Last but not least, there are several GUIs available that will assist you in your searches too: SamSpade http://www.samspade.org SuperScan http://www.foundstone.com NetScan Tools Pro http://www.nwpsw.com

Step 5: DNS Interrogation After identifying all the associated domains,

you can begin to query the DNS. DNS is a distributed database used to map IP addresses to hostnames, and vice versa. If DNS is configured insecurely, it is possible to obtain revealing information about the organization.

One of the most serious misconfigurations a system administrator can make is allowing untrusted Internet users to perform a DNS zone transfer

A zone transfer allows a secondary master server to update its zone database from the primary master

This provides for redundancy when running DNS, should the primary name server become unavailable.

Generally, a DNS zone transfer needs to be performed only by secondary master DNS servers

Many DNS servers, however, are misconfigured and provide a copy of the zone to anyone who asks.

A simple way to perform a zone transfer is to use the nslookup client that is usually provided with most UNIX and Windows implementations. We can use nslookup in interactive mode, as follows: [bash]$ nslookup Default Server: ns1.example.net Address: 10.10.20.2 > 216.182.1.1 Server: ns1.example.net Address: 10.10.20.2 Name: gate.tellurian.net Address: 216.182.1.1

> set type=any > ls -d Tellurian.net. >\> /tmp/zone_out

Step 6: Network Reconnaissance Now that we have identified potential networks, we

can attempt to determine their network topology as well as potential access paths into the network.

To accomplish this task, we can use the traceroute (ftp://www.ee.lbl.gov/traceroute.tar.gz) program that comes with most flavors of UNIX and is provided in Windows. In Windows, it is spelled tracert due to the 8.3 legacy filename issues.

traceroute is a diagnostic tool originally written by Van Jacobson that lets you view the route that an IP packet follows from one host to the next. traceroute uses the time-tolive (TTL) option in the IP packet to elicit an ICMP TIME_EXCEEDED message from each router

traceroute may allow you to discover the network topology employed by the target network, in addition to identifying access control devices (such as an applicationbased firewall or packet-filtering routers) that may be filtering our traffic

Most of what we have done up to this point with traceroute has been command-line oriented. For the graphically inclined, you can use VisualRoute (http://www.visualroute.com), NeoTrace (http://www.neotrace.com), or Trout (http://www.foundstone.com)

Some basic Linux tools - lower level utilities Local System▪ hostname▪ ifconfig▪ who, last

Remote Systems▪ ping▪ traceroute▪ nslookup, dig▪ whois▪ arp, netstat (also local system)

Other tools▪ lsof

Other utilities wireshark (packet sniffing) nmap (port scanning) - more later

Ubuntu Linux▪ Go to System / Administration / Network

Tools – get interface to collection of tools: ping, netstat, traceroute, port scan, nslookup, finger, whois

Windows Sam Spade (collected network tools) Wireshark (packet sniffer) Command line tools▪ ipconfig

Many others…

Determine host name of current system

Usage: hostname E.g. hostnamelocalhost.localdomain // default E.g. hostnamemobile.cs.uwec.edu

Configure network interface Tells current IP numbers for host system Usage: ifconfig

E.g. ifconfig // command alone: display status

eth0 Link encap: Ethernet HWaddr 00:0C:29:CD:F6:D3 inet addr: 192.168.172.128 . . .lo Link encap: Local

Loopbackinet addr: 127.0.0.1 . . .

Basic tool to show users on current system

Useful for identifying unusual activity (e.g. activity by newly created accounts or inactive accounts)

Usage: who E.g. whoroot tty1 Jan 9 12:46paul tty2 Jan 9 12:52

Show last N users on system Default: since last cycling of file -N: last N lines

Useful for identifying unusual activity in recent past

Usage: last [-n] E.g. last -3wagnerpj pts/1 137.28.253.254 Sat Feb 5 15:40 still logged inflinstf pts/0 137.28.191.74 Sat Feb 5 15:38 still logged inrubbleb pts/0 c48.someu.edu Sat Feb 5 14:38 - 15:25 (00:46)

Potential Uses Is system online?▪ Through response

Gather name information▪ Through DNS

Tentatively Identify operating system▪ Based on TTL (packet Time To Live) on each packet line▪ TTL = number of hops allowed to get to system▪ 64 is Linux default, 128 is Windows default (but can be

changed!) Notes

Uses ICMP packets Often blocked on many hosts; more useful within network Usage: ping system▪ E.g. ping ftp.redhat.com▪ E.g. ping localhost

Potential Uses Determine physical location of machine Gather network information (gateway, other

internal systems) Find system that’s dropping your packets –

evidence of a firewall Notes

Can use UDP or ICMP packets Results often limited by firewalls Several GUI-based traceroute utilities available Usage: traceroute system▪ E.g. traceroute cs.umn.edu

[wagnerpj@data ~]$ traceroute cs.umn.edutraceroute to cs.umn.edu (128.101.34.202), 30

hops max, 38 byte packets1 137.28.109.2 (137.28.109.2) 0.247 ms 0.220

ms 0.208 ms2 v101.networking.cns.uwec.edu (137.28.9.1)

0.245 ms 0.229 ms 0.220 ms3 uweauclairehub2-ge50.core.wiscnet.net

(216.56.90.1) 1.315 ms 1.194 ms 1.343 ms4 * * *<ctrl-c>[wagnerpj@data ~]$

H:\>tracert www.google.comTracing route to www.google.akadns.net [64.233.167.99] over a maximum of

30 hops: 

1    <1 ms    <1 ms    <1 ms  v61.networking.cns.uwec.edu [137.28.61.1]2     4 ms     6 ms     3 ms  UWEauClaireHub2-ge50.core.wiscnet.net

[216.56.90.1]3     2 ms     1 ms     2 ms  r-uweauclaire-isp-gig2-0.wiscnet.net

[140.189.8.141]4    17 ms    17 ms    17 ms  chi-edge-08.inet.qwest.net [65.113.85.5]5    18 ms    16 ms    18 ms  chi-core-02.inet.qwest.net [205.171.20.113]6    17 ms    18 ms    19 ms  cer-core-01.inet.qwest.net [205.171.205.34]7    18 ms    19 ms    21 ms  chp-brdr-01.inet.qwest.net [205.171.139.146]8    18 ms    17 ms    18 ms  P11-0.CHICR2.Chicago.opentransit.net

[193.251.129.113]9    15 ms    16 ms    16 ms  Google-EU-Customers-2.GW.opentransit.net

[193.251.249.30]10    16 ms    16 ms    18 ms  216.239.46.1011    21 ms    19 ms    17 ms  64.233.175.3012    18 ms    16 ms    16 ms  64.233.167.99 Trace complete.

Potential Uses Queries nicname/whois servers for

Internet registration information Can gather contacts, names, geographic

information, servers, … - useful for social engineering attacks

Notes Usage: whois domain▪ e.g. whois netcom.com

Domain Name: UWEC.EDURegistrant: University of Wisconsin - Eau Claire 105 Garfield Avenue Eau Claire, WI 54702-4004 UNITED STATESContacts: Administrative Contact: Computing and Networking Services 105 Garfield Ave Eau Claire, WI 54701 UNITED STATES (715) 836-5711 networking@uwec.eduName Servers: TOMATO.UWEC.EDU 137.28.1.17 LETTUCE.UWEC.EDU 137.28.1.18 BACON.UWEC.EDU 137.28.5.194

whois uw%.eduYour search has matched multiple domains.Below are the domains you matched (up to 100).

For specificinformation on one of these domains, please search

on that domain. UW.EDU UWA.EDU UWB.EDU UWC.EDU UWEC.EDU UWEST.EDU UWEX.EDU

….

Potential Uses Query internet name servers Find name for IP address, and vice versa

Notes Now deprecated – generally use dig Sometimes useful when dig fails

Usage nslookup xxxxxxx // name or IP

addr.▪ E.g. nslookup data.cs.uwec.edu▪ E.g. dig data.cs.uwec.edu

Potential Uses Domain Name Service (DNS) lookup utility Associate name with IP address and vice

versa Notes

Many command options General usage: dig <somehost>▪ E.g. dig data.cs.uwec.edu▪ E.g. dig 137.28.109.33

Tracks addresses, interfaces accessed by system

Possible uses Find systems that your system has

recently talked toNotes

arp // display names arp –n // display numeric

addresses

Shows connections, routing information, statistics

Possible uses find systems that your system has recently

talked to, find recently used ports Notes

Many flags▪ netstat // open sockets, etc.▪ netstat –s // summary statistics▪ netstat – r // routing tables▪ netstat – p // programs▪ netstat – l // listening sockets

Lists open files on your systemUseful to see what processes are

working with what files, possibly identify tampering

Usage: lsof

Sam Spade “swiss army knife” of footprinting Has most of the Linux tools Plus other functionality

Usage Start application Fill in name or IP address Choose option desired in menus

Definition: Hardware or software that can display network traffic packet information

Usage Network traffic analysis

Example packet sniffers tcpdump (command line, Linux) wireshark (GUI interface, Linux, Windows

– open source) others…

Packet sniffers only catch what they can see Users attached to hub – can see everything Users attached to switch – only see own traffic Wireless – wireless access point is like hub

Need to be able to put your network interface card (NIC) in “promiscuous” mode to be able to process all traffic, not just traffic for/from itself NIC must support Need privilege (e.g. root in Linux)

Layer 7 – Application (incl. app. content)

Layer 6 – Presentation Layer 5 – SessionLayer 4 – Transport (incl. protocol,

port)Layer 3 – Network (incl. source,

dest)Layer 2 – Data LinkLayer 1 – Physical

Created as tool to examine network problems in 1997

Various contributors added pieces; released 1998

Name change (2007): ethereal -> wireshark

Works with other packet filter formats Information

http://www.wireshark.org Demonstration

Ubuntu – Applications / Internet / Wireshark (as root) Enter your administrative account pw: user Capture/Interfaces/eth0:, Start

Capture window shows accumulated totals for different types of packets

Stop – packets now displayed Top window – packet summary

Can sort by column – source, destination, protocol are useful

Middle window – packet breakdown Click on + icons for detail at each packet level

Bottom window – packet content

Can save a session to a capture file Can reopen file later for further analysis Open capture file

Ubuntu: /home/user/Support/MOBILEcapture.cap W2K3: C:\Support\MOBILEcapture.cap

Identify and follow different TCP streams Select TCP packet, Analyze/Follow TCP Stream MOBILEcapture.cap has http, https, ftp, ssh

streams Any interesting information out there?

HINT: follow stream on an ftp packet

Hunt TCP sniffer Watch and reset connections Hijack sessions Spoof MAC address Spoof DNS name

EtherPEG – image capture on network http://www.etherpeg.com

Basic tools can generate much information

Remember principle of accumulating information Attacker will build on smaller pieces to

get bigger pieces Message to defenders: don’t give

away any information if you can avoid it

McClure S., Joel S. Hacking Exposed 5th .