A SEMINAR
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Transcript of A SEMINAR
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A SEMINAR
ON
BY
ROHIT KAUL CS BITSPILANI
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AGENDA
•Introduction to Computer Networks
•Uses and types
•LANs , WANs , MANs
•Protocols
•Network Security….its need
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CONTINUED..
•Security Areas…….•Modes of attack …..•Safeguarding the systems..•Firewalls and other methods•Network Security.. a Hacker’s perspective
•Summary and conclusions...
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COMPUTER NETWORK ????•Simply an interconnected collection of autonomous computers...•Internet and WWW not networks!!!
•Distributed system
USES•Primarily resource sharing….
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TYPES
•LANs , MANs , WANs , Internet
PROTOCOLS•To reduce design complexity most networks are organised as layers…
•no of layers,names,contents and functions are network specific…..
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Layer 5
Layer 3
Layer 2
Layer 1
Layer 5
Layer 4 Layer 4
Layer 3
Layer 2
Layer 1
Physical layer
Host 1 Host 2
Layern
protocol
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•Infact a protocol is an agreement between the communicating parties on how communication is to proceed…..
•An analogy..
•Application layer,presentation,session,transport,network,datalink,physical layers…..
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SECURITY-ISSUES
•NEED
•4 INTERWINED AREAS...
NETWORKING
PRIVACYAUTHENTICATION
INTEGRITY NON REPUDIATION
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•PRIVACY
•Has to do with keeping info out of the hands of unauthorized users
•Encryption/Decryption
•Secret-key encryption/decryption
•public-key encryption/decryption
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SECRET KEY METHOD
ADV/DISADV
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PUBLIC KEY METHOD (eg RSA)
ADV/DISADV
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•Authentication deals with whom u r talking to before revealing sensitive info
•Integrity control…..no manipulation in data { message received = message sent}
•Non repudiations …no impersonification
•( seeming sender=actual sender )
DIGITAL SIGNATURE
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SIGNING THE DOCUMENT
HOW DOES IT PRESERVE ALL 3?
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UNDER ATTACK!!!
•Denial Of Service (DOS)
mail bombing
spam relaying
smurfing
•Distributed Denial Of Service (DDOS)
•Intrusion attacks
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•IP spoofing
•Malacious programs/scripts
• viruses and worms
• trojans
• vandals
and many more……..
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16Denial of Service Loss of Integrity
BankCustomer
Deposit $1000 Deposit $ 100
Security Threats
Loss of Privacy
m-y-p-a-s-s-w-o-r-d d-a-n
telnet company.orgusername: danpassword:
Impersonation
I’m Bob.Send Me All Corporate
Correspondencewith Cisco.
Bob
CPUCPU
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Protection Against Attacks
Against DOS/DDOS
•Simple call to perpetrator’s ISP•Configure procmail/sendmail
•Use spamassassin
Against intrusion
Encryption algorithms
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Configure a Firewall….
What is a FIREWALL????
Analogy with non computer world!!
Basically a shield which protects systems from unreliable sources on the internet.
…it is a utility,listens to all the ports on the system to open a connection,if detects ..reacts acc to predefined rules.
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•Allows only selected packets <pkt filter>….
•General Methods•Updating through patches,virus detection,password cracks,port scanners. etc•Shifting from windows to LINUX/UNIX
•Ckt gateways and relays...
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IP ADDRESSES…
OUR IDENTITY ON THE NET…
32 bit, written normally as 4 decimal nos of 8 bit each < dotted-decimal notation>,,,eg 202.34.12.23
concepts of classes,netmask,subnetmask other notations,etc etc
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FINDING OUT IP OF UR SYSTEM.?.
Connect to internet,launch MSDOSType netstat -n at the prompt
Active conections:
proto local address state
TCP 203.94.253.183:1025 ESTABLISHED
Ping,netstat,traceroute,WHOIS
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FINDING IP OF A REMOTE SYSTEM
•Through instant messaging softwares
•Through HTTP and scripts
•Through internet relay Chat IRC
•Through e-mail headers
Most common method of getting ips is thru instant mesg softwares like MSN,ICQ,Y
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ICQ
Xx.xx.xx.xx<---------------->yy.yy.yy.yy
MSN
Xx.xx.xx.xx----MSN server--yy.yy.yy.yy
Transfer file,and use netstat….
Prevention..don’t accept file transfer,use wingate???
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IPS BY STUDYING EMAIL HEADERS
Return-path:<[email protected]>
received:from hotmail.com by jammu.bsnl.net.in
(8.9.1/1.1.20.3/5jun04-12:30p.m.)
-----------------------------------------------------
X-originating Ip:[202.15.109.174]
from:simran”<[email protected]>
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GETTING IP USING IRC
/Whois nicknameofthevictim
/whois swordfish
swordfish is [email protected]*rohit koul
swordfish on #chatterz
swordfish using irc.net GlobalNAPs Quincy,MA
swordfish has been idle since………
swordfish…Endof/WHOIS list
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I have the IP..so what???
First step sor any hacking attack…..
All those attacks discussed before can be implemented….
Apart from getting ip…other imp things..cracking softwares,banner grabbing,breaking encryptions,fingerprinting etc but...
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Summary and conclusions
•U c I have left a lot untouched…
•hash functions,DES,blow fish,detailed desciption of RSA ,hacking methods etc
•it is nearly impossible to configure a firewall or create a network that’s 100% fool-proof without compromising on the services to b offered
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Security Objective: Balance Business Needs with Risks
Access SecurityAuthentication
Authorization
Accounting
Assurance
Confidentiality
Data Integrity
Policy ManagementPolicy Management
Connectivity
Performance
Ease of Use
Manageability
Availability
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ANY QUESTIONS?????