Security Attacks

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Security Attacks

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Objectives

• Identify attacker profiles

• Describe basic attacks

• Describe identity attacks

• Identify denial of service attacks

• Define malicious code (malware)

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Attacker Profiles

Attacker Skill Level Motivation

Hacker High Improve Security

Cracker High Harm Systems

Script Kiddie Low Gain Recognition

Spy High Earn Money

Employee Varies Varies

Cyberterrorist High Support Ideology

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• Today, the global computing infrastructure is most likely target of attacks

• Basic Attacks– Physical Attacks– Social Engineering– Password Attacks– Weak Cryptographic Keys– Mathematical Attacks– Birthday Attacks

Understanding Basic Attacks

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Environmental Attacks

• Electricity. Computing equipment requires electricity to function; hence, it is vital that such equipment has a steady uninterrupted power supply.

• Temperature. Computer chips have a natural operating temperature and exceeding that temperature significantly can severely damage them.

• Limited conductance. Because computing equipment is electronic, it relies on there being limited conductance in its environment. If random parts of a computer are connected electronically, then that equipment could be damaged by a short circuit (e.g., in a flood).

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Eavesdropping

• Eavesdropping is the process of secretly listening in on another person’s conversation.

• Protection of sensitive information must go beyond computer security and extend to the environment in which this information is entered and read.

• Simple eavesdropping techniques include – Using social engineering to allow the attacker to read information over the

victim’s shoulder

– Installing small cameras to capture the information as it is being read

– Using binoculars to view a victim’s monitor through an open window.

• These direct observation techniques are commonly referred to as shoulder surfing.

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Wiretapping• Many communication networks employ the use of inexpensive coaxial

copper cables, where information is transmitted via electrical impulses that travel through the cables.

• Relatively inexpensive means exist that measure these impulses and can reconstruct the data being transferred through a tapped cable, allowing an attacker to eavesdrop on network traffic.

• These wiretapping attacks are passive, in that there is no alteration of the signal being transferred, making them extremely difficult to detect.

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Signal Eminations

• Computer screens emit radio frequencies that can be used to detect what is being displayed.

• Visible light reflections can also be used to reconstruct a display from its reflection on a wall, coffee mug, or eyeglasses.

• Both of these require the attacker to have a receiver close enough to detect the signal.

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Acoustic Emissions

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• Dmitri Asonov and Rakesh Agrawal published a paper in 2004 detailing how an attacker could use an audio recording of a user typing on a keyboard to reconstruct what was typed.

microphone to capture keystrokesounds

sound recordingdevice

– Each keystroke has minute differences in the sound it produces, and certain keys are known to be pressed more often than others.

– After training an advanced neural network to recognize individual keys, their software recognized an average 79% of all keystrokes.

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Hardware Keyloggers

• A keylogger is any means of recording a victim’s keystrokes, typically used to eavesdrop passwords or other sensitive information.

• Hardware keyloggers are typically small connectors that are installed between a keyboard and a computer.

• For example, a USB keylogger is a device containing male and female USB connectors, which allow it to be placed between a USB port on a computer and a USB cable coming from a keyboard.

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USB Keylogger

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TEMPEST

• TEMPEST is a U.S. government code word for a set of standards for limiting information-carrying electromagnetic emanations from computing equipment.

• TEMPEST establishes three zones or levels of protection:1. An attacker has almost direct contact with the equipment, such

as in an adjacent room or within a meter of the device in the same room.

2. An attacker can get no closer than 20 meters to the equipment or is blocked by a building to have an equivalent amount of attenuation.

3. An attacker can get no closer than 100 meters to the equipment or is blocked by a building to have an equivalent amount of attenuation.

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Emanation Blockage

• To block visible light emanations, we can enclose sensitive equipment in a windowless room.

• To block acoustic emanations, we can enclose sensitive equipment in a room lined with sound-dampening materials.

• To block electromagnetic emanations in the electrical cords and cables, we can make sure every such cord and cable is well grounded and insulated.

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Faraday Cages

• To block electromagnetic emanations in the air, we can surround sensitive equipment with metallic conductive shielding or a mesh of such material, where the holes in the mesh are smaller than the wavelengths of the electromagnetic radiation we wish to block.

• Such an enclosure is known as a Faraday cage.

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• Not limited to telephone calls or dated credentials • Dumpster diving: digging through trash receptacles to

find computer manuals, printouts, or password lists that have been thrown away

• Phishing: sending people electronic requests for information that appear to come from a valid source. Now includes social networking sites (Facebook, Twitter, etc.)– Often generated by organized attackers. In 2009, ¼ of all

phishing believed to be done by “Avalanche”.

Social Engineering

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Social Engineering

• Unauthorized access to offices– Proper preparation.– Fake credentials– “Tailgating”– Build Relationships (cookies & chocolate)– USB Drops– Reflections off of nearby objects

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• Develop strong instructions or company policies regarding:– When passwords are given out– Who can enter the premises– What to do when asked questions by another

employee that may reveal protected information

• Educate all employees about the policies and ensure that these policies are followed

Social Engineering (soln.)

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How a password is stored?

Password fileUser

Butch:ASDSA 21QW3R50E ERWWER323 … …

hash function

Dog124

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Strong Passwords• What is a strong password

– UPPER/lower case characters– Special characters– Numbers

• When is a password strong?– Seattle1– M1ke03– P@$$w0rd– TD2k5secV

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Password Complexity• A fixed 6 symbols password:

– Numbers 106 = 1,000,000

– UPPER or lower case characters 266 = 308,915,776

– UPPER and lower case characters 526 = 19,770,609,664

– 32 special characters (&, %, $, @, “, |, ^, }, etc.)326 = 1,073,741,824

• 94 practical symbols available– 946 = 689,869,781,056

• ASCII standard 7 bit 27 =128 symbols– 1286 = 4,398,046,511,104

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Odd characters make passwords safer

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Password Length• 26 UPPER/lower case characters = 52 characters• 10 numbers• 32 special characters • => 94 characters available • 5 characters: 945 = 7,339,040,224• 6 characters: 946 = 689,869,781,056• 7 characters: 947 = 64,847,759,419,264• 8 characters: 948 = 6,095,689,385,410,816• 9 characters: 949 = 572,994,802,228,616,704

Longer passwords are better

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Password Validity: Brute Force Test

• Password does not change for 60 days• how many passwords should I try for each second?

– 5 characters: 1,415 PW /sec– 6 characters: 133,076 PW /sec– 7 characters: 12,509,214 PW /sec– 8 characters: 1,175,866,008 PW /sec– 9 characters: 110,531,404,750 PW /sec

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Secure Passwords• A strong password includes characters from at

least three of the following groups:

• Use pass phrases eg. "I re@lly want to buy 11 Dogs!"

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• Software exploitation: takes advantage of any weakness in software to bypass security requiring a password– Buffer overflow: occurs when a computer program

attempts to stuff more data into a temporary storage area than it can hold

Bypass Password

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• Science of transforming information so it is secure while being transmitted or stored

• Does not attempt to hide existence of data; “scrambles” data so it cannot be viewed by unauthorized users

• Encryption: changing the original text to a secret message using cryptography

• Success of cryptography depends on the process used to encrypt and decrypt messages

• Process is based on algorithms

Cryptography

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• Algorithm is given a key that it uses to encrypt the message

• Any mathematical key that creates a detectable pattern or structure (weak keys) provides an attacker with valuable information to break the encryption

Weak Keys

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• Cryptanalysis: process of attempting to break an encrypted message

• Mathematical attack: analyzes characters in an encrypted text to discover the keys and decrypt the data

Mathematical Attacks

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• Birthday paradox:– When you meet someone for the first time, you

have a 1 in 365 chance (0.027%) that he has the same birthday as you

– If you meet 60 people, the probability leaps to over 99% that you will share the same birthday with one of these people

• Birthday attack: attack on a cryptographical system that exploits the mathematics underlying the birthday paradox

Birthday Attacks

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• Category of attacks in which the attacker attempts to assume the identity of a valid user– Man-in-the-middle– Replay

Examining Identity Attacks

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• Make it seem that two computers are communicating with each other, when actually they are sending and receiving data with a computer between them

• Can be active or passive:– Passive attack: attacker captures sensitive data

being transmitted and sends it to the original recipient without his presence being detected

– Active attack: contents of the message are intercepted and altered before being sent on

Man-in-the-Middle Attacks

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• Similar to an active man-in-the-middle attack• Whereas an active man-in-the-middle attack

changes the contents of a message before sending it on, a replay attack only captures the message and then sends it again later

• Takes advantage of communications between a network device and a file server

Replay

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TCP/IP Hijacking

• With wired networks, TCP/IP hijacking uses spoofing, which is the act of pretending to be the legitimate owner

• One particular type of spoofing is Address Resolution Protocol (ARP) spoofing

• Computers on a network keep a table that links an IP address with the corresponding MAC address

• In ARP spoofing, a hacker changes the table so packets are redirected to his computer

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Identifying Denial of Service Attacks

• Denial of service (DoS) attack attempts to make a server or other network device unavailable by flooding it with requests

• After a short time, the server runs out of resources and can no longer function

• SYN attack – Exploits the SYN/ACK “handshake”

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Identifying Denial of Service Attacks (cont)

• Another DoS attack tricks computers into responding to a false request

• An attacker can send a request to all computers on the network making it appear a server is asking for a response

• Each computer then responds to the server, overwhelming it, and causing the server to crash or be unavailable to legitimate users

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Identifying Denial of Service Attacks (cont)

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Identifying Denial of Service Attacks (cont)

• Distributed denial-of-service (DDoS) attack:– Instead of using one computer, a DDoS may use

hundreds or thousands of computers – DDoS works in stages

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Understanding Malicious Code (Malware)

• Consists of computer programs designed to break into computers or to create havoc on computers

• Most common types:– Viruses– Worms– Logic bombs– Trojan horses– Back doors

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Summary

• Attackers– Hacker– Cracker– Script Kiddie– Spy– Employee– Cyberterrorist

• Attacks– Physical Attacks– Password Guessing– Cryptography– Identity Attacks– DoS Attacks– Malware