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490 Cards in this Set

  • Front
  • Back
Each of the following is a layer that protects information security except.

A. products
B. people
C. communication
D. procedures
Communication
Each of the following is a reason why security is becoming increasingly difficult except.

A. speed of attacks
B. slower processors
C. sophistication of attacks
D. faster detection of weaknesses
Slower processors
_____ is a category of attacker who only wants to expose security flaws

A. Hacker
B. Cracker
C. Employee
D. Spy
Hacker
Guarding the availability of information is achieved by.

A. access control
B. closed system authentication
C. wireless protection environment (WPE)
D. frame count check (FCC)
access control
_____ is the science of transforming information so that it is secure while it is being transmitted or stored.

A. Default key transformation (DRT)
B. Access control
C.Steganography
D. Cryptolography
Cryptography
Cryptography depends upon the process called an algorithm that uses a cipher.

True or False
True
Using the same (shared) secret key to both encrypt as well as decrypt is called private key cryptography or symmetric encryption algorithms.

True or False
True
WEP keys must be a minimum of 1,664 bits in length.

True or False
False, 40 bit or 140 bit
WEP can support up to 32 keys, but only one of which can be the default key.

True or False
False, can support only 4 keys
The initialization vector (IV) is a 24-bit value that changes each time a packet is encrypted.

True or False
True
The output of the pseudo-random number generator (PRNG) is the _____ _____.
Key Stream
The _____ is added to the front ("pre-pended") of the ciphertext and is plaintext and is not encrypted
Initialization Vector (IV)
RC4 is a stream _____ that accepts keys up to 128 bits in length and takes one character and replaces it with one character.
cipher
In order for an attacker to be authenticated he only has to discover the _____.
SSID
In a(n) _____ attack and attacker attempts to create every possible key combination by systematically changing one character at a time in possible default key, and then using each newly generated key to decrypt a message.
brute force
Restricting access to authorized users.
Access Control
The underlying process or formula for encrypting and decrypting messages.
algorithm
An attack in which an attacker attempts to create every possible key combination by systematically changing one character at a time in a possible key.
brute force attack
An encryption algorithm
cipher
An encrypted message
ciphertext
In wireless security, two packets that were created from the same initialization vector (IV)
collision
A person who has been hired to break into a computer and steal information.
computer spy
A person who violates system security with malicious intent.
cracker
The science of transforming information so that it is secure while it is being transmitted or stored.
cryptography
Terrorists who attack networks and computer infrastructures in order to cause panic.
cyberterrorists
A checksum value that is based on the contents of the text.
cyclic redundancy check (CRC)
An attack that takes advantage of a previously unknown flaw.
day zero attack
The process of changing a ciphertext into plaintext
decryption
A key value that is used to encrypt wireless data transmissions when they are sent.
default key
An attack that attempts to make a server or other network device unavailable by flooding it with requests.
denial of service (DoS) attack
The process of changing plaintext into ciphertext.
encryption
Restricting access to authorized users.
filtering
A person who uses his or her advanced computer skills to attack computers but not with a malicious intent.
Hacker
Protecting the confidentiality, integrity, and availability of information on the devices that store, manipulate, and transmit the information through products, people, and procedures.
Information Security
A 24-bit WEP value that changes each time a packet is encrypted.
Initialization Vector (IV)
The checksum value generated by WEP.
Integrity Check Value (ICV)
An attack technique that floods the radio frequency spectrum with noise.
jamming
The value that an algorithm uses to encrypt or decrypt a message.
key
The output from a pseudo-random number generator (PRNG).
keystream
An attack method to determining the keystream by analyzing two packets that were created from the same initialization vector (IV).
keystream attack
An attack that intercepts communication from one device and sends a substitute communication to the intended receiver.
man-in-the-middle attack
An access control method that restricts access based on media access control (MAC) address.
Media Access Control (MAC) address filtering
A message in an unencrypted format.
plaintext
Using the same shared secret key to both encrypt and decrypt messages.
Private Key Cryptography
A part of the process for encrypting packages using WEP that generates a keystream.
Pseudo-Random Number Generator (PRNG)
A cipher algorithm used in WEP.
RC4
Unskilled or novice attackers who break into computers to create damage.
Script Kiddies
The process of hiding data so that it cannot be discovered.
Steganography
A cipher that takes one character and replaces it with one character.
Stream Cipher
Using the same shared secret key to both encrypt and decrypt messages.
Symmetric Encryption
A cryptographic key that creates a repeating pattern.
Weak Key
AN IEEE 802.11 cryptography mechanism.
Wired Equivalent Privacy (WEP)
After the IEEE 802.11 standard was ratified in 1999 independent studies identified WEP weakness by the year ----.

A. 2001
B. 2003
C. 2004
D. 2005
2001
The two primary security vulnerabilities of the original 802.11 wireless security mechanism are ____ and _____.

A. Speed and Data Modeling
B. Encryption and Authentication
C. Access Codes and passwords
D. Tokens and Resources
Encryption and Authentication
WPA and WPA2 were created by which organization.

A. IEEE
B. CompTIA
C. Wi-Fi Alliance
D. Wireless Research Resource Group (WRRG)
IEEE
After the security flaws in WEP were publicized, the IEEE TGi task group released a new proposed implementation known as _____.

A. WPA
B. WEP2
C. TKIP
D. Dynamic TKIP
WEP2
_____ is another name for the IEEE 802.11 standard.

A. Robust Security Network (RSN)
B. Wireless Access protection 2 (WAP2)
C. Encryption Model II
D. Enterprise Standard Security (ESS)
Robust Security Network (RSN)
Advanced Encryption Standard (AES) is a block cipher.

True
Flase
True
The IEEE 802.1x standard enforces port security.

True
False
True
Pre - authentication allows a device to become authenticated prior to being turned on.

True
Flase
False, the device must be turned on in order for the device to authenticate.
Wi-Fi Protected Access (WPA) is a subset of IEEE 802.11i

True
False
True
MIC performs encryption by using a per-byte key.

True
False
False
The _____ replaces the Cyclic Redundancy Check (CRC) function in WEP
MIC
Unlike WEP, the _____ is not used for encryption but instead serves as the starting point (seed) for mathematically generating the encryption keys.
Passphrase
_____ allows both AES and TKIP clients to operate in the same WLAN, whereas IEEE 802.11i only recognizes TKIP.
WPA2
The _____ security model should only be implemented as a temporary solution.
Transition
Shared key authentication uses _____ keys for authentication.
WEP
List the three steps that should be taken for the implementing the transitional security model.
1. Block Broadcast SSID
2. Shared Key Authentication.
3. MAC Filtering
When should the personal security model be implemented.
In small office or home environments
Why should AES encryption and decryption be performed in hardware instead of software.
It is heavy and really needs an extra on board chip to process the encryption and decryption.
Does a RADIUS server support IEEE 802.1x
Yes
What is a virtual private network (VPN)
A network that uses a public, unsecured network as if it were a private, secured network.
A block cipher used in IEEE 802.11i
Advanced Encryption Standard (AES)
The encryption protocol in the 802.11i standard.
AES-CCMP
A server on an IEEE 802.1x network that verifies the authentication of devices.
Authentication Server
A device that receives requests in an 802.1x network
Authenticator
A cipher that manipulates an entire block of plaintext at one time.
Block Cipher
Traffic that is sent to all users on the network.
Broadcast
A Web page that wireless users are forced to access prior to being granted access to the wireless network. At a captive portal, users are required to agree to terms of use before being granted access to the network.
Captive Portal
A proposed solution to solve the weak initialization vector (IV) problem by rotating the keys frequently.
Dynamic WEP
The end of the tunnel between VPN devices.
Endpoint
A wireless security model designed for medium to large-size organization such as businesses, government agencies, and universities in which an authentication server is available.
Enterprise Security Model
A device that creates a "trusted" VPN connection between itself and another enterprise trusted gateway.
Enterprise Trusted Gateway
A protocol that is used on IEEE 802.1x networks.
Extensible Authentication Protocol (EAP)
A standard for authentication and key management that can be used for either wired or wireless networks.
IEEE 802.1x
A wireless security standard intended to replace the original WEP-based standard.
IEEE 802.11i
A security device that monitors network activity instead of filtering packets.
Intrusion Detection System (IDS)
A technology developed by the Massachusetts Institute of Technology (MIT) used to verify the identity of network users.
Kerberos
A technology that stores information from a device on the network to improve roaming.
key-caching
A technology that replaces the Cyclic Redundancy Check (CRC) and is designed to prevent an attacker from capturing, altering, and resending data packets.
Message Integrity Check (MIC)
A technology that dynamically generates a new key for each packet and prevents network collisions.
per-packet key
A model for wireless security designed for single users or small office home office (SOHO) settings of 10 or fewer wireless devices.
Personal Security Model
An authentication technique that blocks all traffic until the user is approved.
Port Security
A technology that allows a device to become authenticated to an AP before moving to it.
Pre-Authentication
A technology that uses passphrases for generating encryption keys.
Pre-Shared Key (PSK)
The interval that PSK keys are changed.
Rekey Interval
The process of automatically changing PSK keys are changed.
Rekeying
An authentication server typically used on an IEEE 802.1x network.
Remote Authentication Dial-In User Service (RADIUS)
A virtual private network which is a user-to-LAN connection used by remote users.
Remote-Access VPN
Another name for IEEE 802.11i
Robust Security Network (RSN)
A method of setting permissions to a position or role and then assigning users to that role.
Role Based Access Control (RBAC)
An iteration in a block cipher.
Round
The starting point for mathematically generating an encryption key.
Seed
A passphrase in pre-shared key (PSK) authentication that must be entered in both the access point and wireless device.
Shared Secret
A virtual private network in which multiple sites can connect to other sites over the Internet.
Site-to-Site VPN
A collection of requirements specific to the system or procedure that must be met by everyone.
Standard
The wireless device that requires secure network access in an IEEE 802.1x network.
Supplicant
A 128-bit encryption key used in TKIP
Temporal Key
A technology that replaces WEP encryption.
Temporal Key Integrity Protocol (TKIP)
A model for wireless security that should only be implemented as a temporary solution before upgrading to a more secure model, either the personal security model or the enterprise seccurity model.
Transitional Security Model
A network that uses a public, unsecured network as if it were a private, secured network.
Virtual Private Network (VPN)
A device that aggregates hundreds or thousands of connections together.
VPN Concentrator
A proposed standard standard that addresses the limitations of WEP by adding two new security enhancements.
WEP2 (WEP Version 2)
A subset of 802.11i that addresses encryption and authentication.
Wi-Fi Protected Access (WPA)
The second generation of WPA security , based on the IEEE 802.11i standard.
Wi-Fi Protected Access 2 (WPA2)
An access point that is equipped with additional functionality such as a VPN and an authentication server.
Wireless Gateway
A device that monitors the RF frequency for attacks.
Wireless Intrusion Detection System (WIDS)
A device that performs routing functions by communicating with access points over the RF frequency to determine the most efficient transmission path.
Wireless LAN Mesh Router
Hardware device or software that monitors the RF frequency for rogue access points.
Wireless Sensor.
Explain how WEP violates the "cardinal rule" of cryptography.
Wep creates a detectible pattern
What is a man-in-the-middle attack and how can one be launched against a wireless network.
It is when the communication is intercepted and rerouted through a unauthorized source before continuing on to its destination.
List two ways in which a denial service (DoS) attack can be launched against a WLAN.
Jamming and Disassociation
Explain how and attacker can force a renegotiation to capture SSID.
After causing a dissociation, can send a reassociation frame causing the SSID to be presented.
What is a dictionary attack.
An attack that takes each word from a dictionary and encodes it in the same way a passphrase was encoded.
Two perpendicular planes that are used to create a three-dimensional image of RF radiation patterns.
Azimuth and Elevation
Practices that establish the benchmark for actions using the network
Baseline Practices
An amplifier that boosts the RF signal before it is injected into the device that contains the antenna.
Bidirectional Amplifier
Practices that outline the structure and scope of a wireless security plan and how it will be implemented.
Design and Implementation Practices
The measure of the antenna gain less the cable loss at the receiver and the receiver's sensitivity.
Effective Receiving Sensibility
Nonvolatile storage chip used in computers and other devices that can be programmed and erased multiple times electrically.
Electrically-Erasable Programmable Read-Only Memory (EEPROM)
A record of events on the wireless network that is recorded by the access point.
Event Log
The difference between the strongest RF signal in an area and the weakest signal that a receiver can process.
Fade Margin
Software that is embedded into hardware.
Firmware
An attenuator that limits the RF power by a set amount.
Fixed-loss Attenuator
A metal rod inserted into the earth for grounding purposes.
Ground Rod
The process of determining the likelihood that a vulnerability is a risk to the organization.
Impact Analysis
A device that limits the amplitude and disturbing interference voltages by channeling them to the ground.
Lightening Arrestor
A rough calculation of all known elements of the link to determine if the signal will have the proper strength when it researches the other end of the link.
Link budget
The repository of SNMP data.
Management Information Base (MIB)
An antenna that is typically used in outdoor areas.
Panel Antenna
The protection of equipment and networking infrastructure itself from unauthorized users from reaching the physical equipment in order to use, steal, or vandalize it.
Physical Security
An SNMP-based tool that is used to monitor LANs that are connected through a wide area network.
Remote Monitoring (RMON)
A device that amplifies or increases the amplitude of an RF signal.
RF amplifier
A device that decreases the RF signal.
RF attenuator
Modifying the settings of an access point after a firmware upgrade or simiar modification.
RF site tuning
The process of determining the nature of the risks to the organization's assets.
Risk Assessment
An antenna for an access point that looks like a slim rod approximately half an inch in diameter and may vary in length from four to six inches
Rod Antenna
An antenna that divides the standard 360-degree pattern into four quarters, each with its own transmitter and antenna.
Sectorized Antenna
The process of examining the current security of an organization.
Security Auditing
A document or series of documents that defines the defense mechanisms an organization will employ to keep information secure.
Security Policy
A TCP\IP protocol that allows computers and network equipment to gather data about network performance.
Simple Network Management Protocol (SNMP)
A device with the SNMP management software that collects data.
SNMP Management Station
An alert message sent to the management station.
SNMP trap
An attack that relies on tricking or deceiving someone to access a system.
Social Engineering
Software that is loaded onto a network device that will be managed using SNMP.
Software Agent
A device that has a single input connector and multiple output connectors.
Splitter
The measure of the overall RF level of a system.
System Operating Margin (SOM)
An amplifier that increases the RF signal level before it is injected into the transmitting antenna.
Unidirectional Amplifier
An attenuator that allows the user to set the amount of loss.
Variable-Loss Attenuator
A tool that compares the asset against a database of known vulnerabilites and produces a discovery report that exposes the vulnerability and assesses its severity.
Vulnerability Scanner
Collection of methods used to ensure a computer system is secure
Computer Security
Collection of methods used to ensure multiple computer systems and devices that are connected together are protected
Network Security
Collection of methods used to ensure data stored and processed is secure
Information Security
Collection of methods used to ensure data and processing systems are available to authorized subjects upon request
Information Assurance
The 'C' in CIA
Confidentiality
The 'I' in CIA
Integrity
The 'A' in CIA
Availability
To ensure that information is accessed only by those whose access is authorized, and never by anybody else
Confidentiality
To ensure that information is created, altered, or deleted by authorized people only, and never by anybody else
Integrity
To ensure that information and the processing system is available for use by authorized people when they need it
Availability
What does the graphic represent
Encryption\Decryption Process
Unique bit sequences that algorithms rely on.
Encryption Keys
Should be hard to determine (long, random, and changed periodically)
Encryption Keys
Should be kept secret at all times
Encryption Keys
_____ algorithms use the same key for encryption and decryption
Symmetric
_____ algorithms use different keys for encryption and decryption
Asymmetric
public/private key cryptography
Asymmetric Algorithms
_____ _____ are easy to obtain and create a detectable pattern that makes breaking the encryption easy – should be avoided as much as possible
Weak keys
Act of deliberately accessing computer systems and networks without authorization
Hacking
Act of exceeding the ones authority in a system
Hacking
Implies preparation and persistent multiple attempts when searching for an unpatched system’s vulnerability
Hacking
Implies several common categories – unstructured, structured, and highly-structured threats
Hacking
May involve a variety of levels of technical expertise
Hacking
Individual attackers only – insiders or outsiders
Unstructured Hacking Threats
Attack for a short time only (months as the longest)
Unstructured Hacking Threats
Have little financial backing
Unstructured Hacking Threats
Have low level of technical expertise – download and run software created by others (can’t create a code)
Script Kiddies
Don’t attack specific targets – search for targets where a particular vulnerability is not patched
Script Kiddies
Fastest growing group (89% of malicious activity)
Script Kiddies
Possess significant technical expertise – are able to create a code
Hackers
Known for attacking a wide variety of targets
Hackers
Responsible for about 9% of malicious online activity
Hackers
Possess exceptional technical expertise – able to find new vulnerabilities and create tools used for attacks
Elite Hackers
Responsible for about 2% of malicious online activity
Elite Hackers
Represented by criminal organizations – target large amounts of money transferred over online systems
Structured Threats
Imply more planning, better financial backing, longer attacks, and collusion with insiders
Structured Threats
Responsible for fraud, extortions, thefts, forgeries, embezzlements, etc.
Structured Threats
Represented by large groups of people – separatist groups, terrorist organizations, and nations
Highly Structured Threats
Common goal – to affect another nation’s critical infrastructures (water, electricity, oil/gas refineries, finance, communications)
Highly Structured Threats
Imply years of preparation, large attacker groups, vast financial backing, and rely on insiders and spies
Highly Structured Threats
Use information warfare as the mean – commonly target information and processing equipment
Highly Structured Threats
May also use information as a weapon
Highly Structured Threats
The unconstrained medium leads to potential security issues
major disadvantage of wireless
Wireless signal can be intercepted by an attacker – can run encryption breaking, denial-of-service, etc. attacks
Disadvantage of Wireless
The original IEEE 802.11 standard implied few weak security features – addressed basic access control, encryption, and authentication
Disadvantage of Wireless
Intended to guard the availability of information – only allows authorized traffic and connections to an AP
Access Control
Defined as Layer 2 filtering by the IEEE standard – restricts access to the WLAN at the MAC layer
Access Control
Commonly implemented as MAC address filtering – using 48-bit addresses in the source address field
Access Control
Can be implemented permissive or restrictive way – commonly depending on the security policy
Access Control
_____ filtering implies manually entering unauthorized MAC addresses into the AP – all other devices would be allowed to the network
Permissive
_____ filtering implies manually entering authorized MAC addresses into the AP – all other devices would not be allowed to the network
Restrictive
Requires wireless clients to supply security credentials prior to associating with a wireless network
Authentication
Leads to granting or denying access to the new device
Authentication
Two basic types – Open System and Shared Key
Authentication
Wireless clients scan for beacon frames from access points – retrieve SSID of the wireless network
Authentication, Open System (“SSID Filtering”)
Clients include the SSID of the network to be joined into association request frames they send to the AP
Authentication, Open System (“SSID Filtering”)
The AP compares the SSID received to the one it uses and authenticates the client device in case of a match
Authentication, Open System (“SSID Filtering”)
The AP responds with the association response frame – contains an acceptance/rejection notice
Authentication, Open System (“SSID Filtering”)
Default on most access points – used for simplicity
Authentication, Open System (“SSID Filtering”)
Implies the AP sending a block of clear text (challenge) to the wireless client that requests to join the network
Shared Key Authentication
The client encrypts the challenge with a preconfigured WEP key and sends the resultant cipher to the AP
Shared Key Authentication
The AP decrypts the cipher and compares the plaintext to the original challenge sent – authenticates the client in case the two strings match
Shared Key Authentication
WEP encryption is used rarely today – modern devices use other algorithms or hashing functions
Shared Key Authentication
Optional – devices use Open System one by default
Shared Key Authentication
Encryption algorithms must work well when implemented both in hardware and software
Efficient
Secret keys used should be long and random, and must be changed periodically
Reasonably Strong
Packet-level encryption is needed
Self-synchronizing
Must meet the guidelines set by the US Department of Commerce to be exported overseas
Exportable
The implementation shouldn’t be enforced
Optional
WLAN Cryptography Objectives include being _____, Reasonably strong, Self-synchronizing, Exportable, and Optional.
Efficient
WLAN Cryptography Objectives include being Efficient, _____ _____, Self-synchronizing, Exportable, and Optional.
Reasonably strong
WLAN Cryptography Objectives include being Efficient, Reasonably strong, _____-_____, Exportable, and Optional.
Self-synchronizing
WLAN Cryptography Objectives include being Efficient, Reasonably strong, Self-synchronizing, _____, and Optional.
Exportable
WLAN Cryptography Objectives include being Efficient, Reasonably strong, Self-synchronizing, Exportable, and _____.
Optional
Described within the original IEEE 802.11 standard
Wired Equivalent Privacy (WEP) Encryption
Relies on a single secret key used on both client and the AP at a time – a symmetric encryption algorithm
Wired Equivalent Privacy (WEP) Encryption
Uses keys of a minimum length of 40 bits – with vendors adding an option to use longer 104-bit keys
Wired Equivalent Privacy (WEP) Encryption
Employs the RC4 encryption algorithm, pseudo-random numbers, single XOR logical operation – not strong
Wired Equivalent Privacy (WEP) Encryption
Nowadays, both 40 and 104-bit keys are considered weak and can provide limited security of data only
Wired Equivalent Privacy (WEP) Encryption
Five options exist – carry different strength and format
WEP Encryption, Key Options
Under the Key Options of WEP Encryption, a 40-bit key created by entering _ ASCII characters
5
Under the Key Options of WEP Encryption, 40-bit key created by entering __ hex characters
10
Under the Key Options of WEP Encryption, 104-bit key created by entering __ASCII characters
13
Under the Key Options of WEP Encryption, 104-bit key created by entering __hex characters
26
Under the Key Options of WEP Encryption, A hexadecimal ______ consisting of 16 ACSII characters entered – used to generate encryption keys
passphrase
Under the Key Options of WEP Encryption, A hexadecimal passphrase consisting of __ ACSII characters entered – used to generate encryption keys
16
An incompatibility issue exists between vendors that discourages use of _____– different keys may be generated from the same sequence of 16 characters
passphrases
Wireless devices hold up to _____ WEP keys at once – different keys may be used to encrypt traffic at various locations (work, home, etc)
four
Wireless devices hold up to four WEP keys at once – _____ keys may be used to encrypt traffic at various locations (work, home, etc)
different
One of the keys is designated as _____ key and used for encrypting data – may be different on both ends
default
MAC frames carry a _-bit field that identifies the index of the key that’s being used – data will be decrypted with the key that matches the one used for encryption
2
MAC frames carry a 2-bit field that identifies the _____ of the key that’s being used – data will be decrypted with the key that matches the one used for encryption
index
___ frames carry a 2-bit field that identifies the index of the key that’s being used – data will be decrypted with the key that matches the one used for encryption
MAC
The keys and their order must be _____ on the access point and the wireless clients
same
Changing default key on the _____ device requires no changes on the access point – simplifies administration
client
Using different WEP keys per client is used to ______ security greatly – rarely used nowadays
increase
The shared secret key is concatenated by a __-bit initialization vector (IV) – value that increments every time a packet is encrypted
24
The shared secret key is concatenated by a 24-bit _____ _____ – value that increments every time a packet is encrypted
initialization vector (IV)
– an integrity check value (ICV) – is calculated via cyclic redundancy check (CRC) and appended to the end of the message
A checksum
A checksum – an _____ _____ _____ – is calculated via cyclic redundancy check (CRC) and appended to the end of the message
integrity check value (ICV)
A checksum – an integrity check value (ICV) – is calculated via _____ _____ _____ and appended to the end of the message
cyclic redundancy check (CRC)
A checksum – an integrity check value (ICV) – is calculated via cyclic redundancy check (CRC) and appended to the _____of the message
end
The _____ / _____ pair is fed into RC4 stream cipher that generates a random bit sequence (“keystream”) that’s equal in length to the text plus the ICV
shared key/IV
The shared key/IV pair is fed into _____ stream cipher that generates a random bit sequence (“keystream”) that’s equal in length to the text plus the ICV
RC4
The shared key/IV pair is fed into RC4 stream cipher that generates a _____ _____ _____ (“keystream”) that’s equal in length to the text plus the ICV
random bit sequence
The shared key/IV pair is fed into RC4 stream cipher that generates a random bit sequence (“keystream”) that’s equal in _____ to the text plus the ICV
length
The ciphertext is created by bit-by-bit _____ the text plus ICV and the keystream
XORing
The ciphertext is created by bit-by-bit XORing the text plus _____ and the keystream
ICV
The ciphertext is created by bit-by-bit XORing the text plus ICV and the _____
keystream
The IV is added to the _____ of the ciphertext and the encrypted data is ready for transmission
front
The _____ separates the IV from the ciphertext and by combines the IV with the appropriate secret key
receiver
The receiver separates the __ from the ciphertext and by combines the IV with the appropriate secret key
IV
The receiver separates the IV from the _____ and by combines the IV with the appropriate secret key
ciphertext
The receiver separates the IV from the ciphertext and by combines the __ with the appropriate secret key
IV
The receiver separates the IV from the ciphertext and by combines the IV with the appropriate _____ _____
secret key
___ algorithm generates a keystream
RC4
______is XORed with the ketystream – the text and the original ICV are extracted, followed by CRC check
Ciphertext
Ciphertext is _____ with the ketystream – the text and the original ICV are extracted, followed by CRC check
XORed
Ciphertext is XORed with the _____– the text and the original ICV are extracted, followed by CRC check
ketystream
Ciphertext is XORed with the ketystream – the text and the original ICV are _____, followed by CRC check
extracted
Ciphertext is XORed with the ketystream – the text and the original ICV are extracted, followed by ___ check
CRC
Requires manual management – difficult on mid-sized and large ESS networks and in case of frequent addition and removal of wireless clients
MAC Address Filtering
Subject to human errors – lead to denial of connection to legitimate clients and may open potential venues for a variety of attacks
MAC Address Filtering
MAC addresses are easy to capture using sniffers, through reassociation, or by breaking physical security
MAC Address Filtering
Once captured, they can be used for joining the network
MAC Address Filtering
Numerous software tools implement MAC spoofing – allows changing the MAC address in software
MAC Address Filtering
Some NICs allow for a substitute physical address to be used – spoofed MAC addresses can be presented
MAC Address Filtering
Because of its vulnerabilities and lack of flexibility, _____ _____ _____ can’t be used within enterprise
MAC address filtering
Based on matching SSID only – easy to discover
Open System Authentication
With Open System Authentication, SSID can be found on the device that is already authenticated – as result of a _____ security breach
physical
With Open System Authentication, by default, SSID is broadcasted by access points within ______ frames they send – can be captured by sniffers
beacon
With Open System Authentication, some access points can be configured to prevent including the SSID into beacon frames – may prevent _____ devices from freely roaming between them
legitimate
With Open System Authentication, _____ SSIDs are well-known and published – may not be changed by administrators timely
default
With Open System Authentication, the SSID is transmitted in _____ during the initial negotiation – easy to capture using sniffers
plaintext
With Open System Authentication, an attacker can also force negotiation by sending a forged _____ frame to a wireless device – will attempt to reconnect to the AP exposing SSID
disassociation
With Open System Authentication, The SSID can be captured from the _____– multiple wireless tools are freely available online
negotiation
Use of Open System authentication is _____ when security is a concern
discouraged
With Shared Key Authentication, An attacker only needs to know one ____ – can be captured via physical access to device or through shoulder surfing
key
With Shared Key Authentication, The access point sends a _____ in plaintext – vulnerable to interception
challenge
With Shared Key Authentication, Both the challenge and the client’s response can be captured – then the key that was used for ______ can be derived
encryption
With Shared Key Authentication, An attacker can try to derive the key by running a _____ _____ or a dictionary attack against the message
brute force
With Shared Key Authentication, An attacker can try to derive the key by running a brute force or a _____ attack against the message
dictionary
With Shared Key Authentication, The key must be configured on every device – difficult within an ___ environment
ESS
With Shared Key Authentication, Inherits additional vulnerabilities in case ___ keys are used – they are short and not truly random
WEP
Both authentication types (Open and Shared Key) provided within the _____ _____ standard are not secure – strong authentication is achieved by using digital certificated only
IEEE 802.11
In brute force attack, An attacker tries decrypting the message with every possible key – generated by changing one ___ at a time
bit
A _____-_____ attack is effective for short keys, infeasible for longer ones.
brute-force
In a _____ attack, an attacker Takes each word from a predefined dictionary and encodes it same way the passphrase is encoded
dictionary
In a dictionary attack, Attacker compares the encoded dictionary words against those in the encrypted _____
frame
_____ may be used for generating WEP leys – not too secure and not recommended
Passphrases
Uses 24-bit IV and 40- or 104-bit secret key – result in a 64- or 128-bit encryption key – short and nonsecure
WEP Encryption
WEP Encryption Transmits IV in _____– makes the effective secret part of encryption keys only 40 or 104 bit long
plaintext
WEP Encryption Repeats IV every 16,777,216 times – a busy AP sending and receiving ~ 900 packets each second would repeat the IV every _____ hours
five
Some wireless systems always start with the same IV after the system is _____ and then follow the same sequence of incrementing IVs – easy to capture
restarted
It has been proven that several IVs – weak IVs – can reveal key bytes after _____ _____
statistical analysis
As result, WEP keys of either 40- or 128-bit key length can be derived after as few as _ _____ frames– takes around four hours on a high-usage WLAN
4 million
RC4 uses a pseudo-random number generator to create the keystream – no _____ _____ numbers
true random
___ isn’t the most effective security algorithm
RC4
_____ algorithm is not the strongest one for integrity
CRC
Subject to IV replay, key stream, bit-flipping, and other attacks – with freeware tools widely available online
WEP Encryption
A number of secure authentication technologies is available – _____\_____ solutions can be used for authenticating wireless users
RADIUS/DIAMETER
WEP is lightweight and compatible with older devices –same hardware can be used for stronger _____
encryption
_____ WEP keys can be used instead of static ones
Dynamic
___ may be replaced by a stronger hashing function
CRC
An attacker floods the RF spectrum with noise that represents itself as valid traffic being transmitted
DoS Jamming
All wireless devices sense the medium before transmitting (CSMA/CA) – see the channel as busy and none of them attempts transmitting
DoS Jamming
An attacker sends a series of disassociation frames to the client – forces it to repeatedly disassociate and reassociate with the AP
DoS Reassociation
This kind of attack disables transmission of the actual data
DoS Reassociation
Makes it seem that two parties are communicating with each other directly – with a third party actually intercepting, sending and receiving data between them
Man-in-the-Middle (“TCP/IP Hijacking”)
In a _____ Man-in-the-Middle (“TCP/IP Hijacking”) attack, the attacker captures the data that is being transmitted and then sends it on to the original recipient without his presence being detected
Passive
In a _____ Man-in-the-Middle (“TCP/IP Hijacking”) attack, the attacker captures the data that is being transmitted and alters them before sending them on
Active
Implemented by attackers setting up their own AP and tricking wireless devices to communicate to it
Man-in-the-Middle (“TCP/IP Hijacking”)
In a SYN Flood DoS, it Exploits the OSI _____ layer vulnerabilities
Transport
In a SYN Flood DoS, Upon receiving a client’s SYN request, the server responds with an ___
ACK
In a SYN Flood DoS, The server waits for the client’s final reply – keeps the connection open with _____ reserved for it
memory
In a SYN Flood DoS, Attackers make servers unavailable by flooding them with SYN requests – while final replies _____ arrive
never
In a SYN Flood DoS, Waiting for too many replies _____ the server’s resources, making it nonfunctional and unavailable for legitimate requests for service
exhausts
Confidentiality through strong encryption and secure authentication are required on a WLAN – the original _____ _____ standard didn’t offer a good solution
IEEE 802.11
The same group tried addressing WEP problems via two intermediate solutions – _____ and _____ _____
WEP2 and Dynamic WEP
Two comprehensive solutions – ______ and _____ – were developed by the IEEE and the Wi-Fi Alliance, correspondingly
802.11i and Wi-Fi Protected Access (WPA)
Two comprehensive solutions – 802.11i and Wi-Fi Protected Access (WPA) – were developed by the _____ and _____, correspondingly
IEEE and the Wi-Fi Alliance
Developed by the same IEEE Task Group i (TGi) that developed the original WEP
WEP2
Offers two security enhancements – longer keys and support for Kerberos authentication
WEP2
Naturally extends key+IV space to 128-bits – used to be much more secure than using 64-bit keys
WEP2
Enabled wireless clients to use encrypted tickets issued by secure Kerberos server for identity verification
WEP2
The tickets would carry client data clients – identify, allowed actions, etc – would expire after several hours
WEP2
Doesn’t prevent collisions – makes identification of two packets derived from the same IV possible
WEP2, Disadvantages
Still uses lightweight but not secure RC4 algorithm
WEP2, Disadvantages
Inherits disadvantages of Kerberos – single point of failure, clock synchronization, vulnerability to dictionary attacks, etc.
WEP2, Disadvantages
Not much more secure than the original WEP – was not widely adopted as replacement for WEP
WEP2, Disadvantages
Solves the weak IV problem by rotating the keys frequently – makes cracking more difficult
Dynamic WEP
Uses different keys for unicast and broadcast traffic – broadcast keys are same for all users on the particular subnet and the access point
Dynamic WEP
Unicast keys are unique for each user session, generated dynamically, and changed when the user roams to a new AP, or logs out and logs back in
Dynamic WEP
Doesn’t protect against man-in-the-middle and DoS attacks – was quickly replaced by better solutions
Dynamic WEP
Developed by a group that originated from the IEEE TGi task group that was disbanded
IEEE 802.11i
Provides solid wireless security model – addresses both secure encryption and authentication
IEEE 802.11i
Includes multiple new features such as key caching, pre-authentication, etc.
IEEE 802.11i
Also known as the Robust Security Network (RSN)
IEEE 802.11i
A new standing IEEE committee ensures that new additions to the 802.11 standard don’t carry their own security issues
IEEE 802.11i
The RC4 stream cipher is replaced by the _____ _____ _____ algorithm (block cipher)
Advanced Encryption Standard (AES)
AES replaced ___ and is considered secure for many years to come – US government encryption standard
DES
Plaintext is divided into ___-bit blocks – with entire block encrypted at a time via multiple rounds
128
___ supports 128-, 192-, and 256-bit long keys – with 10, 12, or 14 encryption rounds used, respectively
AES
Longer keys and higher number or rounds affect the overall _____ of the system that uses AES
performance
___is computationally heavy – mobile devices require hardware implementation on a dedicated chip for better performance
AES
Wireless Authentication was accomplished according to the _____ _____ standard – originally developed for wired networks (supported by Windows 2000 SP4 or later OS)
IEEE 802.1x
Implements port security – all network traffic to mobile clients that try accessing the network is blocked until their identities are verified by an authentication server
IEEE 802.1x Authentication
802.1x authenticates in the _____only – session may be vulnerable to a man-in-the-middle attack
beginning
A wireless client contacts the AP with a request to join the WLAN – the communication port is put to the unauthorized state (i.e. only 802.1x traffic is allowed)
802.11i Authentication Process
The AP requests the new device to verify its identity – the client sends identity information to the AP
802.11i Authentication Process
The AP passes identity data onto an authentication server – secured by digital certificates and encryption
802.11i Authentication Process
The authentication server verifies the client’s identity – notifies the access point about its decision
802.11i Authentication Process
The client joins the network if authenticated only
802.11i Authentication Process
The port is set to unauthorized state upon logoff again
802.11i Authentication Process
The Extensible Authentication Protocol over LANs (EAPOL) is used between the client and the AP
802.11i Authentication Process
The communication between the access point and the authentication server is ruled by appropriate protocol (RADIUS or DIAMETER)
802.11i Authentication Process
Requires a Public Key Infrastructure (PKI) to operate
802.11i Authentication Process
In the 802.11i standard, _____ _____ Enables caching clients’ credentials on the network to avoid retransmitting them in case a client roams away from the AP and later returns
Key Caching
In the 802.11i standard, _____ _____ makes roaming between APs faster by allowing mobile clients to authenticate to the new AP before moving to it
Pre-Authentication
In the 802.11i standard, the device would send a _____-_____ packet that is routed to the remote AP – through the AP the device is currently authenticated with
pre-authentication
Created as an intermediate measure while the IEEE 802.11i standard was under development
Wi-Fi Protected Access (WPA)
A MAC layer subset of the 802.11i standard – addresses both encryption and authentication
Wi-Fi Protected Access (WPA)
Replaces original WEP by stronger Temporary Key Integrity Protocol (TKIP) encryption
Wi-Fi Protected Access (WPA)
Allows using either IEEE 802.1x protocol or pre-shared key (PSK) for authentication of wireless clients
Wi-Fi Protected Access (WPA)
Encryption solution – much stronger than WEP
Temporary Key Integrity Protocol (TKIP)
After accepting a device’s credentials, the authentication server uses 802.1x to produce a unique master key for that user session
Temporary Key Integrity Protocol (TKIP)
Within the Temporary Key Integrity Protocol (TKIP), The _____ key is distributed to the client and the AP
master
Substitutes this temporary key for the WEP base key and constructs a new 128-bit key for every packet – these have limited lifetimes and are replaced frequently
Temporary Key Integrity Protocol (TKIP)
Optional in standard WLAN, required in WPA
Temporary Key Integrity Protocol (TKIP)
MIC provides better protection against forgeries
Temporary Key Integrity Protocol (TKIP)
Replaces the CRC function used by WEP – complicates capturing and altering, and then resending data
Message Integrity Check (MIC) Function
CRC is not strong enough – vulnerable to modification of both the message and the CRC field
Message Integrity Check (MIC) Function
MIC function is much stronger than CRC
Message Integrity Check (MIC) Function
Offers an optional countermeasure – if a MIC error occurs, clients are disassociated, with new associations prevented for one minute
Message Integrity Check (MIC) Function
Used within TKIP encryption
Message Integrity Check (MIC) Function
Dynamically generated keys significantly increase time between consequent possible collisions – ensure that a valid packet isn’t recorded and then retransmitted
Temporary Key Integrity Protocol (TKIP)
Temporary Key Integrity Protocol (TKIP) Increases the size of the IV to __ bits and uses it as a sequence number for each packet
48
Both transmitter and receiver initialize the packet sequence to zero whenever new _____ keys are set
TKIP
Works on the same hardware as WEP – older clients and APs may require software or firmware upgrades
Temporary Key Integrity Protocol
Within Temporary Key Integrity Protocol, Encryption, The device starts with having two keys – a 128-bit encryption _____ key and a 64-bit Message Integrity Check (MIC) key value
temporal
Within Temporary Key Integrity Protocol, Encryption, The device starts with having two keys – a 128-bit encryption temporal key and a 64-bit _____ _____ _____ key value
Message Integrity Check (MIC)
Within Temporary Key Integrity Protocol, Encryption, The temporal key is XORed with the sender’s ___ address to create an Intermediate Value I
MAC
Within Temporary Key Integrity Protocol, Encryption, The temporal key is XORed with the sender’s MAC address to create an Intermediate Value _
I
Within Temporary Key Integrity Protocol, Encryption, Intermediate Value I is mixed with a _____ number (former IV field in WEP) to produce Intermediate Value II – entered into the PRNG
sequence
Within Temporary Key Integrity Protocol, Encryption, Intermediate Value I is mixed with a sequence number (former IV field in WEP) to produce Intermediate Value __ – entered into the PRNG
II
Within Temporary Key Integrity Protocol, Encryption, Intermediate Value I is mixed with a sequence number (former IV field in WEP) to produce Intermediate Value II – entered into the _____
PRNG
Within Temporary Key Integrity Protocol, Encryption, The random number generator generates a _____
keystream
Within Temporary Key Integrity Protocol, Encryption, The MIC key and the sender’s and receiver’s MAC addresses are all run through a ___function – a new MIC value obtained
MIC
Within Temporary Key Integrity Protocol, Encryption, The ciphertext is obtained via _____ the keystream and the plaintext message with the MIC value appended to it bit-by-bit
XORing
Wi-Fi Protected Access (WPA) Authentication is accomplished by using either _____ _____ protocol or pre-shared key (PSK) technology
IEEE 802.1x
Wi-Fi Protected Access (WPA) Authentication is accomplished by using either IEEE 802.1x protocol or _____ _____ technology
pre-shared key (PSK)
_____authentication uses a passphrase as a seed to generate the encryption key – has to be entered manually on each device
PSK
PSK authentication uses a passphrase as a seed to generate the encryption key – has to be entered _____ on each device
manually
Implementation of IEEE 802.1x protocol is too complex for _____ wireless networks – enterprises only
SOHO
PSK is vulnerable to possible decryption of _____ _____ and insertion of fake packets – this problem is fixed in AES-based WPA2
short packets (ARP)
PSK is vulnerable to possible decryption of short packets (ARP) and insertion of _____ packets – this problem is fixed in AES-based WPA2
fake
Based on the final IEEE 802.11i standard – allows both AES and TKIP clients to operate on the same WLAN
WPA2
More secure than WPA – allows using AES encryption
WPA2
More flexible than 802.11i – allows using AES or TKIP
WPA2
Supports IEEE 802.1x and PSK authentication
WPA2
Most popular solution for SOHO wireless networks
WPA2
Implies using currently installed or inexpensive new equipment temporarily – until equipment that supports better security features can be implemented
Transitional Security Model
Used when better security models aren’t feasible for financial or organizational reasons – with a plan to purchase and install better equipment in future
Transitional Security Model
Should be considered as temporary solution only – with best available authentication and encryption configured
Transitional Security Model
Users must be aware of weak spots of implementation
Transitional Security Model
easy to implement and supported by all 802.11 access points
Shared key authentication
fast and supported by all 802.11 access points (longest keys should be used, passphrase use is not recommended since weak keys are created)
WEP encryption
broadly supported (disabled by default, should be used restrictive way, not suitable for frequent changes in wireless client base)
MAC filtering
broadly supported (enabled by default, not suitable for many roaming clients)
Disable SSID broadcast
Suitable for SOHO wireless networks with up to 10 users and no secure authentication server available
Personal Security Model
Implies using PSK authentication
Personal Security Model
Relies on WPA for encryption – with older devices using WPA (TKIP) and newer ones using WPA2 (AES)
Personal Security Model
Assumes implementation of the latest WPA version supported by wireless equipment
Personal Security Model
Provides intermediate level of security – but commonly much more secure than transitional model
Personal Security Model
With Personal Authentication, A passphrase that’s manually entered on the _____ is used as a starting seed value for encryption key generation
AP
With Personal Authentication, The passphrase can be between _ and __ characters – with special characters and spaces allowed
8 and 63
With Personal Authentication, Passphrases of at least __ ASCII characters or at least __ hex digits are recommended
20\24
In Personal Security Model Authentication, Implements the _____ feature – security keys are automatically changed after a set number of packets (rekey interval) is sent
rekeying
In Personal Security Model Authentication, Implements the rekeying feature – security keys are automatically changed after a set number of packets _____ _____ is sent
(rekey interval)
Within the Personal Security Model Encryption,_____ _____ uses TKIP thus compatible with existing WEP infrastructure (more secure than WEP)
WPA-based Encryption
Within the Personal Security Model Encryption, _____ _____ allows using both TKIP and AES thus provides maximum flexibility
WPA2-based Encryption
Suitable for mid-sized and large organizations – implies that a secure authentication server is available
Enterprise Security Model
Implies connections to a RADIUS (DIAMETER) server via the IEEE 802.1x authentication protocol
Enterprise Security Model
Relies on WPA for encryption – with older devices using WPA (TKIP) and newer ones using WPA2 (AES)
Enterprise Security Model
Assumes implementation of the latest WPA version supported by wireless equipment
Enterprise Security Model
Provides the highest level of security of all models
Enterprise Security Model
WPA Authentication =
PSK or 802.1x
WPA Encryption =
TKIP
WPA Encryption Hardware =
WEP
WPA Complexity =
Lowest
WPA2 Authentication =
PSK or 802.1x
WPA2 Encryption =
TKIP or AES
WPA2 Encryption Hardware =
WEP or Special
WPA2 Complexity =
Average
IEEE 802.11i Authentication =
802.1x
IEEE 802.11i Encryption =
AES
IEEE 802.11i Encryption Hardware =
Special
IEEE 802.11i complexity =
Highest
Transitional Security Model Authentication =
Best Available
Transitional Security Model Based on Solution =
Basic Features
Transitional Security Model Protection =
Minimal
Transitional Security Model Usability =
Temporary
Personal Security Model Authentication =
PSK
Personal Security Model Based on Solution =
WPA or WPA2
Personal Security Model Protection =
Good
Personal Security Model Usability
SOHO
Enterprise Security Model Authentication =
802.1x
Enterprise Security Model Based on Solution =
WPA or WPA2
Enterprise Security Model Protection =
Best
Enterprise Security Model USability
Large Networks
Allow connect wireless users to secure corporate networks via secure data transmission channels – tunnels – through public networks
Virtual Private Networks (VPN)
Imply configuring the two endpoints of the tunnel – each one may include a software, a firewall, or a hardware VPN concentrator
Virtual Private Networks (VPN)
Can be based on a variety of secure protocols, such as PPTP, IPSec, SSL, etc.
Virtual Private Networks (VPN)
Does not support roaming between access points
Virtual Private Networks (VPN)
Constantly monitor the RF medium for attacks – search traffic patterns via hardware or software sensors
Wireless Intrusion Detection Systems (WIDS)
Can be passive (send an alert or produce an alarm) or active (take an action when sensing an attack)
Wireless Intrusion Detection Systems (WIDS)
Identify attacks based on a database of known traffic patterns – signatures – or on abnormal network activities (“anomaly-based IDS”)
Wireless Intrusion Detection Systems (WIDS)
Signature-based IDS are limited to detecting attacks that are in the database only while anomaly-based IDS may produce multiple false alarms
Wireless Intrusion Detection Systems (WIDS)
Using Wireless Intrusion Detection Systems, Hardware Sensors, Separate hardware devices or access points that operate in a special _____ _____
scan mode
Using Wireless Intrusion Detection Systems, hardware can detect signals from _____ access points by comparing their RF signal with the database of known APs
rogue
Wireless Intrusion Detection Systems, Software Sensors May be installed on wireless devices for acting as a “_____” of mobile sensors
mesh
Wireless Intrusion Detection Systems, Software Sensors May be installed on a _____ for detecting rogue APs that connect to the wired network
server
A Web page that wireless users are forced to visit before they are granted access of some kind
Captive Portal
Used to notify users of wireless policies and rules, to advertise products, or to authenticate users via s secure server before they are granted access
Captive Portal
Used in hotspots and other public locations – commonly takes users to a “Terms and Conditions” page
Captive Portal
802.11i Authentication
Open System Authentication
Shared Key Authentication
WEP Encryption
WPA PSK Authentication