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Network Reconnaissance
What is?
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Military reconnaissance
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a mission conducted to confirm or deny prior
intelligence (if any) about enemy threat and or the
terrain of a given area.
Network reconnaissance
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process of acquiring information about a network
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Why?
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Hackers use reconnaissance as the first step in an
effective attack
Seeing what is on the "other side of the hill" is crucial
to decide what type of attack to launch
Generally, goals of reconnaissance on a target
network are to discover:
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IP addresses of hosts
Accessible UDP and TCP ports
OS type
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Footprinting/Fingerprinting steps
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Information Gathering
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Locate the network
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Which ports and applications are accessible
OS Fingerprinting
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Which machine is actively connected to the network and reachable
Open ports and underlying applications
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What addresses can be targeted and are available for additional scanning and analysis
Identify active machines
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accumulating data regarding a specific network environment, usually for the purpose of
finding ways to intrude into the environment
Identifying targeted Oss as well as systems response
Network mapping
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Create blueprint of organization
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Information Gathering
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Get data regarding network environment such as
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Organization web site, Location, contact person, Phone
number
Common Tools
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Registrar query : whois
Domain name and resource lookup
Search Tools
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Locate the network range
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What range of IP addresses are available for
scanning and further enumeration
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Common Tools : whois
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Tool: WHOIS Search
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WhoIs – Query of Internet Registries
 Ref: http://www.arin.net/community/rirs.html
 AfriNIC – Africa
 APNIC - Asia/Pacific
 ARIN – North America
 LACNIC - Central and South America
 RIPE NCC – Europe, Middle East, Central Asia
 InterNIC– ICANN Public Domain Name Registration Info
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3rd Party Whois Tools
 Geektools - http://www.geektools.com/whois.php
 DomainTools – http://www.domaintools.com/
 DNSStuff – http://www.dnsstuff.com
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Tool: WHOIS web interface
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Tool: - Google
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Google, Yahoo, Live.com, etc.
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Gather information about a targeted
organization
Evaluate web sites for known security issues
Identify files that are accidentally exposed to
the public
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Tool: - Google search
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Helpful Google Queries
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Related sites:
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Search a specific site:
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related:www.someaddr.com
site:www.someaddr.com search_terms
Use Google to search group or blog postings
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Tool: – Google operators
Google Advanced Operators
AND: “+”
OR: “|”
Synonym: “~”
site:www.jeffersonwells.com
inurl:robots.txt
link:www.jeffersonwells.com
intitle:“jefferson wells”
filetype:xls
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Tool: NSLOOKUP
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Queries Domain Name Server information
 IP and Domain Name Mapping
 Zone Transfer – Dumps entire table
 Check mail server
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Tool: NSLOOKUP
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Zone Transfer – Dumps entire table
$ nslookup
> server = A.B.C.D
> ls somedomain.com
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Tool: NSLOOKUP
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MX record
$ nslookup
> set type = MX
> somedomain.com
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Network Identifier Tools
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Identifying active computers and services
Common Tools
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ping, ping6
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help verifying whether a host is active
traceroute, traceroute6
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determine the route to a node
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Tool: ping
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ping [hostname|ip_address]
ping6 [hostname|ip_address]
ping -R [hostname|ip_address]
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Tool: traceroute
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tracert
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Windows
traceroute
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Unix
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Tool: How Traceroute work
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Launch a probe packet towards DST, with a TTL of 1
Every router hop decrements the IP TTL of the packet by 1
When the TTL hits 0, packet is dropped, router sends ICMP TTL Exceed
packet to SRC with the original probe packet as payload
SRC receives this ICMP message, displays a traceroute “hop”
Repeat from step 1, with TTL incremented by 1 each time, until..
DST host receives probe, returns ICMP Dest Unreachable
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Tool: Traceroute Report Hop
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Traceroute packet with TTL of 1 enters router via the ingress interface.
Router decrements TTL to 0, drops packet, generates ICMP TTL Exceed
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ICMP packet dst address is set to the original traceroute probe source (SRC)
ICMP packet src address is set to the IP of the ingress router interface
Traceroute shows a result based on the src address of the ICMP packet
The above traceroute will read:172.16.2.1 10.3.2.2
You have NO visibility into the return path or the egress interface used
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Tool: Traceroute Latency Calculation
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How is traceroute latency calculated?
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Timestamp when the probe packet is launched
Timestamp when the ICMP response is received
Calculate the difference to determine round-trip time
Routers along the path donot do anytime “processing”
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They simply reflect the original packet’s data back to the SRC
Many implementations encode the original launch timestamp into the probe packet,
to increase accuracy and reduce state
Most Importantly: only the ROUNDTRIP is measured
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Traceroute is showing you the hops on the forward path
But showing you latency based on the forward PLUS reverse path. Any delays on
the reverse path will affect your results!
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Tool: Interprete Traceroute DNS
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Interpreting DNS is one of the most important
aspects of correctly using traceroute
Information you can uncover includes:
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Physical Router Locations
Interface Types and Capacities
Router Type and Roles
Network Boundaries and Relationships
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Tool: Traceroute Reading Tips
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Router’s name may include Exchange Point
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Router names may be the IATA 3-letter code of the nearest
airport or CLLI code in their node name
Other abbreviation
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MAE, NAP, PAIX
http://www.sarangworld.com/TRACEROUTE/showdb-2.php3
Interface name
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Tool: Common Location US Major Cities
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Tool: Common Location Major Cities
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Tool: Common Interface Naming
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Tool: Router Type/Role
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Knowing the role of a router can be useful
But every network is different, and uses different naming
conventions
May not always follow naming rules
Generally speaking, May need guessing the context and get a
basic understanding of the roles
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Core routers–CR, Core, GBR, BB
Peering routers–BR, Border, Edge, IGR, Peer
Customer routers–AR, Aggr, Cust, CAR, GW
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Tool: DNS Interface type
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Most networks will try to put interface info into DNS
Though this many not always be up to date
Many large networks use automatically generated DNS
As well as capacity, and maybe even the make/model of
router
Examples:
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xe-11-1-0.edge1.Washington1.Level2.net
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XE-#/#/# is Juniper 10GE port. The device has at least 12 slots
It’s at least a 40G/slot router since it has a 10GE PIC in slot 1
It must be Juniper MX960, no other device could fit this profile
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Tool: Sample Traceroute
$ traceroute www.hellers.com
$ traceroute www.mit.edu
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Identifying Active Machines
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Attackers will want to know if machines are alive
before they attempt to attack. One of the most basic
methods of identifying active machines is to perform
a sweep
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Common Tools
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ping, traceroute
Network scanning tools
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nmap, superscan
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Finding Open Ports
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Open services
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Common tools
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Port scanning tools
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nmap, superscan
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OS Fingerprinting
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Passive fingerprint
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Sniffing technique
Examine packets for certain characteristics such as
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The IP TTL value
The TCP Window Size
The IP DF Option
The IP Type of Service (TOS) Option
Active Fingerprint
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Injects the packets into the network
Examines the subtle differences that exist between different vendor implementations of
the TCP/IP stack
Common tools : nmap
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Mapping the Network
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Gained enough information to build network map
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Network mapping provides the hacker with a
blueprint of the organization.
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May use manual or automated ways to compile this
information
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Summary
Method
Technique
Common Tools
Information gathering
Passive
Whois, nslookup
Determining network range
Passive
RIPE, LACNIC, APNIC, ARIN
Identify active machines
Active
ping, hping, traceroute, nmap,
SuperScan
Finding open ports/applications
Active
nmap, Amap, SuperScan
Active/passive
nmap, Winfigerprint, P0f,
Xprobe2, ettercap
OS fingerprinting
Mapping the network
Active
CartoReso, traceroute, NeoTrace
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Q&A
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