Network Security Assignment 1: DNS, WEP, SMTP, and TCP/IP Attacks

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NETWORK SECURITY

Network Security-CSC 8421 ASSIGNMENT-1 (Task-1)

DNS-Domain Name Service
The internet contains a large number of devices which are connected to the severe and share data
with each other. These devices can be connected by using a domain name. The domain name
shows the address of that particular devices. The domain name is easy to remember as it is
written in a common language. The Devices are identified by IP address which is difficult to
understand so the Domain Name Service converts the Domain Name into IP address. The
Domain Name Services uses the address of the website such as www.xyzWebsite.com and
convert it into their corresponding IP address such as 198.105.232.7.
There are two types of request which is received by the DNS, they can be requested from outside
of that domain and inside of that domain. The request is handled according to the authoritative
server. There are possibilities that the requested is treated by the Internet Service Provider (ISP)
or transfer it to the other authoritative source which can answer the following request. Every
domain name has their Don=main name service so the updation can be performed separately
with each case. The DNS is treated like the Address book or Phonebook which have all the
details about the particular web pages and also they have the details regarding the host of that
website. The steps followed by the DNS for converting Domain Name into IP address:
Request Information
The request is made with the server for a particular hostname. This request s proceed by the
DNS. The required hostname is checked in the DNS cache i.e. the recently loaded or recently
requested page. If the requested page is not found then the DNS Query is generated.
Recursive DNS server
The DNS search for the required address by checking with other Recursive DNS server. The ISP
resolver is called for resolving the requested problem. There are multiple users using the same
resolver.
Root Name Server
If the Recursive DNS server is unable to answer the request then the Root Name Server starts
processing the request. The control is transfer where the appropriate answer can be found. The
possible answer can be found at Top Level Domain so this Recursive DNS server shifted the
control to the TLD (.com, .edu, .us, etc.).
Authoritative DNS server
These services have the authority for all the detail information about the Specific Host or
domain. The chance of finding the answer is high in this as all the detail information is contained
by this server.

Responding to the request
After the finding of the required domain, the answer or the requested page is sent to receiver
after retrieval of information.
WEP-Wireless Equivalent Protocol
The WEP-Wireless Equivalent Protocol is a protocol used for security purpose while using
Wireless Network. The standard Wireless network is used for providing the connection for
different devices wirelessly. The wireless network is easy to hack by hackers and any device
connected to that wireless network can easily be a hack and the data can be misused by the
unauthorized user. The WEP work on the encryption technique for providing physical security to
each device and linking them to the network. All the wireless of 802.11 is able to use this
protocol. This protocol uses the WEP frame for each security purpose. The Wireless Network
requires more security so the encryption technique is used for converting the simple text into
complicated text which will be difficult to crack by a hacker or unauthorized user.
Figure 1: WEP Encryption
The following image shows the Encryption of the WEP in which plain text is converted into
Cipher Text. The Seeds are used for making plain text encrypted and will be easily transferred
over Wireless Network.
There are two methods used with WEP:
 Open System Authentication – In this method user don’t have to provide their credential
for access the data or web page or other devices.
 Shared Key Authentication – In this authentication method clients have to use WEP key
for authentication. There is a Clear Text Challenge, which is needed to be clear by the
client for authentication.

SMTP-Simple Mail Transfer Protocol
SMTP-Simple Mail Transfer Protocol is a protocol used for transferring of the mail over the
internet. It is the standard protocol used for providing all the featured services related to the
email. The protocol is secure and safe for interchanging of the email over the large network i.e.
TCP/IP. This Protocol work on the application layer which is responsible for the delivery of the
email. Internet Engineering Task Force (IETF) maintain the SMTP and the linking between
different Nodes such as Remote Email Provider. There are four key components included in the
SMTP:
Mail User Agent (MUA) – These are the user or clients which uses the services for transferring
email. These agents request for the mail service to the server.
Mail Submission Agent (MSA) – These type of agent comes under the category of server used
for transferrin of mail. The server provides the platform for transferring the mail.
Mail Transfer Agent (MTA) – The MTA is the agent which are responsible searching of the
domain and the transferring the email to the specific node.
Mail Delivery Agent (MDA) – MDA provides service related to the delivery of the mail. This
agent is responsible for the delivery of the mail without any error.
Figure 2: SMTP Mail Transferring
The image shows two types of mail Outbound and Inbound Mail. The Outbound mail is transfer
from the user to the server. In Inbound Mail the Mail is transferred from server to the user. In
both transmissions, the SMTP participate in the transmission process between different nodes.

Network Security-CSC 8421 ASSIGNMENT-1 (Task-3)

Studying Attacks on TCP/IP Protocols
Working with the internet requires a protocol for connecting with the internet network. The
TCP/IP protocols provide the connection between the computers or a system using a secure and
robust network. The connectivity of the device is set in such a way that the packets are selected,
complied and send them to the right location. The TCP – Transmission Control Protocol is the
upper layer which is responsible for the transmission of the packet from source to destination.
This protocol also compiles the packet and convert it to the useful information or data for the
source. IP – Internet Protocol deals with the location aspect and responsible for the sending and
receiving of the packets at the correct location. It works like the map or navigation for packets of
information.
There is a big issue related to the security of the TCP/IP protocol. There are many hackers and
fraud people waiting for attacking TCP/IP protocols. These protocols connect multiple systems
with each other for sharing information or other types of data. There are many holes which can
be used for attacking the protocols. There are different layer considered in these protocols, in
which the attacks are usually done on the Internet layer and Host-to-Host layer. There are some
attacks on TCP/IP which includes:
Network Sniffers
Network Sniffers enable to access all the important information form the network and provide
the capability to reform the message. This technique allows other hackers to connect with you
and access all the information.
Port Scans
There are multiple ports are available for users, s any unauthorized or unwanted person can use
these port for attacking. The port scanning can be done by these hackers to check which port is
open and available.
TCP SYN or TCP ACK Flood Attack
The client sends the request to the server for requested packets and waits for the response. The
Server accepts their request and starts sending the packets. There is the continuous transmission
of the ACK packet but there no opening of Session so this will cause waiting of the session and
the other will get denied for the server access.

Figure 2: TCP SYN or TCP ACK Flood Attack
TCP Sequence Number Attack
TCP generate sequence number when the packet is sent to the server. The hacker can possibly
take control of the session and also can generate a duplicate sequence number. This duplicate
sequence number can be the same as the original sequence number. This will put the whole
control of transmission into hacker's hand.
Figure 3: TCP Sequence Number Attack
TCP/IP Hijacking
The attacker can hijack the host and can disconnect the host from the network. this process
allows the hacker to put another host in the network which can access the information available
on the network.
Figure 4: TCP/IP Hijacking
Smurf Attacks

The Smurf Attack is the type of attack which sends a PING as a broadcast message on the
network. All the host have to reply on this PING which results in high traffic and load on the
server. This also allows the hackers to access the information from multiple systems who replied
for the PING.
There are lots of Attacks which can harm the client’s system as well as a server so the security
needs to be managed.

References
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Mahmood, RZ and Fathil, AF 2019, April, High Speed Parallel RC4 Key Searching Brute
Force Attack Based on FPGA. In 2019 International Conference on Advanced Science and
Engineering (ICOASE) (pp. 129-134), IEEE.
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<https://searchsecurity.techtarget.com/definition/Wired-Equivalent-Privacy> [Accessed 10
Aug. 2019].
Techopedia, 2019. What is Simple Mail Transfer Protocol (SMTP)? - Definition from
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<https://www.techopedia.com/definition/1710/simple-mail-transfer-protocol-smtp>
[Accessed 10 Aug. 2019].