Midterm Exam part-3

Question 1

how does the Certificate authority work?

Answer 1

independent and trusted through reputation org. that have info on true parties of public keys. can be verified with digital signature, check to see if still valid and check revocation list

Question 2

what is non-repudiation?

Answer 2

means that the sender can not claim they did not send a message. this is b/c digital signatures can only be validated by parties that know the private and public keys and these are the sender and receivers.

Question 3

what is the basic operation of quantum key encryption?

Answer 3

one time kys
keys as long as message
keys show signs of tamper if eavesdroppers see them.
thousands of years to crack

Question 4

name some VPN types:

Answer 4

Virtual Private Networks: cryptography is used for all communications over an un-trusted network (such as the web to a company).
types:
host to host-pc to a server
*Remote access VPN : pc to private LAN through a VPN gateway on edge of the LAN
*site-to-site VPN: 2 LAN’s using VPN gateways communicate over a VPN on the web to reach one another.

Question 5

what is TLS and how does it relate to VPN’s?

Answer 5

TLS= Transport Layer Security is the same thing as SSL Secure Socket Layer

• this is the cryptography used to encrypt the vpn connections.
• used in host to host vpn and remote access VPN’s.
• only requires web browser with ssl support and no software for computer side. server must have software or the vpn gateway must support ssl.
• *TLS only provides security to TLS/SSL aware applications like HTTP or some web-servers.

Question 6

what is the diff. between IPSEC Transport and Tunnel mode?

Answer 6

IPSEC Transport is used to connect 2 hosts over VPN and use encryption that the border routers/firewalls can’t read. *costly
-IPSEC Tunnel Mode: only the connection between sites starting & ending at the VPN gateways is encrypted, once inside site it is unincripted. (cheaper) no need to set-up each device in network.

Question 7

what is access control?

Answer 7

policy-driven control of access to systems, data and dialogues. **limit attackers and employees access to internal resources.

Question 8

what is the saying “death of the Perimeter”?

Answer 8

network admins say this b/c the idea of creating a 100% secure network is impossible. esp. with BYOD of today.

Question 9

what is flooding?

Answer 9

the attacker sends more requests than the victim can handle. this is used in a denial of service attack.

Question 10

what is spoofing?

Answer 10

when an attacker hides their ip address by changing it so that it is not their real ip address.
*they can’t get replies from the victim though.

Question 11

what are backscatter options?

Answer 11

this is when an attacker does a denial of service attack to a network while using a spoofed (made up) ip address. the victim sends back replies to the made up/ spoofed ip address and inadvertently these replies go to a real computer causing them an issue. (called backscatter).

Question 12

what are the diff/ types of attack packets that a sender/attacker can send in a Dos attack?

Answer 12

SYN Flood: transmission control protocol - connection request.
*Ping Flood: ICMP/Echo request
HTTP flood: webserver/web application flood.

Question 13

what does a SYN flood do?

Answer 13

Dos attack: the SYN- synchronous TCP(transmission control protocol) packets sent requesting connections until the ram is used up and crashes.

Question 14

what does the Ping flood do?

Answer 14

Dos attack: pings (ICMP) internet control message protocol packets (/echo requests) are sent to use up the bandwidth and cpu cycles of the victim causing it to shutdown.

Question 15

what does the HTTP flood do?

Answer 15

Dos attack: webserver is targeted with web page requests/ HTTP application requests and this uses up all the Ram and CPU causing it to crash.

Question 16

what are bots?

Answer 16

Intermediaries: hosts infected with malware are remotely controlled and used in a denial of service attack called a distributed Dos attack.

Question 17

how does ARP poisoning work/.?

Answer 17

an attacker creates a series of ARP replies with its own Mac address claiming it is the gateways address (uses real gateways ip and the attackers mac) and forwards it to all hosts on the LAN except the real gateway. then all computers route traffic intended for the real gateway to the attackers computer since their ARP tables are now incorrect and switches only look at mac addresses so they can’t catch this mistake.

Question 18

what is Radius?

Answer 18

a type of server/ client protocol that provides authentication and authorization to certain servers, files and the authorized supplicant (user) ability to alter, read or copy files.

Question 19

what is EAP and its role in authentication protocol 802.1x?

Answer 19

EAP- Extensible Authentication Protocol: each time a host connects to a switch then the switch sends an EAP start msg. to the radius server. the server sends a MS-CHAP request to the host and if the host replies correctly then the host is allowed on the network. EAP governs this process.

Question 20

what does Extensible mean?

Answer 20

EAP- (Extensible Authentication Protocol)
easy to add new authentication method and structure of EAP does not change.
**no new upgrades needed the Radius server and Supplicant both automatically utilize the new protocols.

Question 21

diff. between wep and WPA?

Answer 21

WEP uses 24 bit key length IV’s that are easy to crack while WPA uses 48 bit key length IV’s and is not vulnerable to hacking. WPA will not defend against man in the middle attacks.