The document discusses network security and its importance in protecting networks and data from breaches and threats. It defines network security as involving access control, antivirus software, firewalls, encryption, and other measures. It then provides background information on security threats, both internal and external, and physical and data attacks. Types of malware like viruses, worms, and trojan horses are explained along with examples. The role of antivirus software in virus protection is also covered.

1. NETWORK
SECURITY

2. Network Security protects your network and data from breaches,
intrusions and other threats. ... Network Security involves access
control, virus and antivirus software, application security, network
analytics, types of network-related security (endpoint, web, wireless),
firewalls, VPN encryption and more.
INTRODUCTION

3. Computer and network security help keep data and equipment safe by
giving only the appropriate people access. Everyone in an organization should
give high priority to security, because everyone can be affected by a lapse in
security. Theft, loss, network intrusion, and physical damage are some of the
ways a network or computer can be harmed.
A technician’s primary responsibilities include data and network security.
You may have to repair, adjust, and install equipment. You need to know how to
configure settings to keep the network secure, but still keep it available to those
who need to access it. You will ensure that software patches and updates are
applied, antivirus software is installed, and antispyware software is used. You
may also be asked to instruct users on how to maintain good security practices
with computer equipment.
BACKGROUND INFORMATION FOR LEARNERS

4. ● Physical: Events or attacks that steal, damage, or destroy such
equipment as servers, switches, and wiring.
● Data: Events or attacks that remove, corrupt, deny access to, allow
access to, or steal information.
SECURITY ATTACKS

5. PHYSICAL ATTACK

6. DATA ATTACK

7. Threats to security can come from inside or outside an organization, and the
level of potential damage can vary greatly. Potential threats include the
following:
Internal: Employees who have access to data, equipment, and the network.
Internal attacks can be characterized as follows:
❖ Malicious threats are when an employee intends to cause damage.
❖ Accidental threats are when the user damages data or equipment
unintentionally.
External: Users outside an organization who do not have authorized access to
the network or resources. External attacks can be characterized as follows:
❖ Unstructured attacks, which use available resources, such as
passwords or scripts, to gain access to and run programs designed to
vandalize.
❖ Structured attacks, which use code to access operating systems and
software.

8. MALICIOUS AND ACCIDENTAL THREAT

9. UNSTRUCTURED ATTACK

10. STRUCTURED ATTACK

11. ● Virus is attached to small pieces of computer code, software, or
document. The virus executes when the software runs on a
computer.
● Worm is a self-replicating program that is harmful to networks. A
worm uses the network to duplicate its code to the hosts on a
network, often without any user intervention.
● Trojan horse technically is a worm. It does not need to be attached
to other software. Instead, a Trojan threat is hidden in software that
appears to do one thing, and yet behind the scenes it does
another.
TYPES OF MALWARE

12. VIRUS
8 Examples of
Computer Virus:
1. CryptoLocker
2. ILOVEYOU
3. MyDoom
4. Storm Worm
5. Sasser & Netsky
6. Anna Kournikova
7. Slammer
8. Stuxnet

13. ● CryptoLocker - Released in September 2013, CryptoLocker spread through email attachments and
encrypted the user’s files so that they couldn’t access them. The hackers then sent a decryption key in
return for a sum of money, usually somewhere from a few hundred pounds up to a couple of grand.
Cost of the malware: With 500,000 victims, CryptoLocker made upwards of $30 million in 100 days.
● ILOVEYOU - It’s been 15 years since ILOVEYOU was let loose on the internet. By today’s standards
it’s a pretty tame virus, but in 2000 it was the most damaging malware event of all time. Likely,
ILOVEYOU inspired many hackers to wield their keyboard as a weapon. The malware was a worm that
was downloaded by clicking on an attachment called ‘LOVE-LETTER-FOR-YOU.TXT.vbs’. Cost of the
malware: $15 billion.
● MyDoom - MyDoom, like ILOVEYOU, is a record-holder and was the fastest-spreading email-based
worm ever. MyDoom was an odd one, as it hit tech companies like SCO, Microsoft, and Google with a
Distributed Denial of Service attack. 25% of infected hosts of the .A version of the virus allegedly hit
the SCO website with a boatload of traffic in an attempt to crash its servers. Cost of the malware: $38
billion.

14. ● Storm Worm - Storm Worm was a particularly vicious virus that made the rounds in 2006 with a
subject line of ‘230 dead as storm batters Europe’. Intrigued, people would open the email and click on
a link to the news story and that’s when the problems started. By July 2007, Storm Worm was picked
up in more than 200 million emails. Cost of the malware: An exact cost is yet to be calculated.
● Sasser & Netsky - 17-year-old Sven Jaschan created Sasser & Netsky, two worms, in the early
noughties. Sasser & Netsky are actually two separate worms, but they’re often grouped together
because the similarities in the code led experts to believe they were created by the same person.
Sasser spread through infected computers by scanning random IP addresses and instructing them
to download the virus. Netsky was the more familiar email-based worm. Netsky was actually the
more viral virus, and caused a huge amount of problems in 2004. Cost of malware: Around $31 billion.
● Anna Kournikova - Jan De Wit, a 20-year-old Dutch man, wrote the virus as ‘a joke’. The subject
was “Here you have, ;0)” with an attached file called AnnaKournikova.jpg.vbs. Anna was pretty
harmless and didn’t do much actual damage, though De Wit turned himself into police anyway. Cost of
the malware: $166,000.

15. ● Slammer - While most of the malware on this list strictly hit computers, Slammer was created with
broader ambitions. Slammer is the kind of virus that makes it into films, as only a few minutes after
infecting its first victim, it was doubling itself every few seconds. 15 minutes in and Slammer had
infected half of the servers that essentially ran the internet. The Bank of America’s ATM service
crashed, 911 services went down, and flights had to be cancelled because of online errors. Slammer,
quite aptly, caused a huge panic as it had effectively managed to crash the internet in 15 quick
minutes. Cost of the malware: Around $1 billion.
● Stuxnet - Stuxnet is easily the scariest virus on the list as it was built by government engineers in
the US with the intention of obstructing nukes from being built in Iran. Stuxnet spread by a USB thumb
drive and targeted software controlling a facility in Iran that held uranium. The virus was so effective it
caused their centrifuges to self-destruct, setting Iran’s nuclear development back and costing a lot of
money. Cost of the malware: Unknown.

16. WORM
5 Examples of Worm:
1. Internet Worms
2. Email Worms
3. Instant Messaging
Worms
4. File-Sharing Worms
5. IRC Worms

17. ● Internet Worms - Like they do with computer networks, computer worms also target popular
websites with insufficient security. When they manage to infect the site, internet worms can replicate
themselves onto any computer being used to access the website in question. From there, internet
worms are distributed to other connected computers through the internet and local area network
connections.
● Email Worms - Email worms are most often distributed via compromised email attachments. They
usually have double extensions (for example, .mp4.exe or .avi.exe) so that the recipient would think
that they are media files and not malicious computer programs. When the victims click on the
attachment, copies of the same infected file will automatically be sent to addresses from their contacts
list.
● Instant Messaging Worms - Instant messaging worms are exactly the same as email worms,
the only difference being their method of distribution. Once again, they are masked as attachments or
clickable links to websites. They are often accompanied by short messages like “LOL” or “You have to
see this!” to trick the victim into thinking that their friend is sending them a funny video to look at.

18. ● File-Sharing Worms - Although illegal, file-sharing and peer-to-peer file transfers are still used
by millions of people around the world. Doing so, they are unknowingly exposing their computers to the
threat of file-sharing worms. Like email and instant messaging worms, these programs are disguised as
media files with dual extensions.
● IRC Worms - Internet Relay Chat (IRC) is a messaging app that is mostly outdated nowadays but
was all the rage at the turn of the century. Same as with today’s instant messaging platforms,
computer worms were distributed via messages containing links and attachments. The latter was less
effective due to an extra layer of protection that prompted users to accept incoming files before any
transfer could take place.

19. TROJAN HORSE
5 Types of Trojan
Horse:
1. Backdoor Trojans
2. Downloader Trojans
3. Distributed Denial-of-
Service Trojans
4. Banking Trojans
5. Fake Antivirus Trojans

20. ● Backdoor Trojans - As the name suggests, these types of Trojan horses have a backdoor of sorts,
a secret passage through which hackers can access your computer and take control of it. Depending on
how sophisticated they are, backdoor Trojans can be used to monitor your web traffic and online
activity, run and/or terminate tasks and processes, upload files without your knowledge, and change
your computer settings.
● Downloader Trojans - Downloader Trojans don’t have a backdoor component that would allow
hackers direct access to your computer, but they still perform actions on your computer that could
benefit the hacker. Namely, these Trojan horses are programmed to download a variety of files and
programs to your hard drive. These can include misleading apps, configuration settings, and upgrades
to the malware that’s installed on your PC.
● Distributed Denial-of-Service Trojans - Distributed Denial-of-Service (DDoS) Trojans are
types of malware designed to carry out attacks against computer networks. They are usually
downloaded and installed on numerous computers at once via spam mail campaigns, turning those
machines into parts of a botnet. These Trojans have a backdoor component, which allows hackers to
activate their botnet army to perform coordinated attacks.

21. ● Banking Trojans - With the growing popularity of online banking services, banking Trojans have
become more common than ever. In the first six months of 2018, these Trojan horses have overtaken
ransomware as the most widespread form of malicious software. As their name suggests, these
Trojans are designed to steal the victims’ financial information and online banking credentials through
the use of phishing techniques.
● Fake Antivirus Trojans - Although they have been around for well over a decade, fake antivirus
Trojans are still very common and powerful. They are downloaded the same way as all other Trojans –
via compromised email attachments, suspicious links, and visits to malicious websites. Once installed,
they masquerade as antivirus software and constantly inform the victim about non-existent security
threats found on their computer.

22. Known as antivirus software, is software designed to detect, disable, and remove
viruses, worms, and Trojans before they infect a computer. Commonly used antivirus are
Norton, Kaspersky, Eset, Mcafee, Trend Micro, Avast, Avira, AVG and SmadAV.
SmadAV antivirus is used in TESDA Assessment for Computer Systems Servicing
NC II. It is a lightweight antivirus software which provides decent protection form all kind of
nasty viruses. This antivirus software is based on Indonesia but became so popular
worldwide because you can use it with any other antivirus software to make an extra layer
of protection.
It has the following key features:
● Works with any other antivirus software like AVG, AVAST, Panda etc.
● Very light weight and takes low resource to run
● Best USB protection to stop spreading virus through USB flush drive
● Cleans infected computer and fix the registry changed by the viruses
● Adds new viruses in the SmadAV database regularly and keep protected
● Updates automatically with the new versions of SmadAV (Pro-version)
VIRUS PROTECTION SOFTWARE

23. How to download and Install?
● Step 1. Access http://www.smadav.net/ website and click on Free Download
● Step 2. Wait till save as window appears. Save the file on the Desktop
● Step 3. Double click on the file from the desktop
● Step 4. Click OK with language selection (English)
SmadAV

24. SmadAV
● Step 5. Click Next on the Welcome Wizard ● Step 6. Accept the license agreement and click
Next

25. SmadAV
● Step 7. Click Next with Desktop shortcut option ● Step 8. Click Install

26. SmadAV
● Step 9. Click Launch and Finish

27. Activity 1:
Direction. Identify the following statement. Select your answer from the box
below. Write your answer on the space provided before each number. Answers can be
selected more than once.
___________________1. Jayson creates a fake bank website and published it to the internet.
___________________2. Events or attacks that steal, damage, or destroy such equipment
as servers, switches, and wiring.
___________________3. It is a self-replicating program that is harmful to networks.
___________________4. Onel De Guzman created the I love You Virus that can slow down
computers and corrupt files.
___________________5. Kevin is angry on his manager. As revenge, he inflicted virus on his
manager’s computer.
ACTIVITIES

28. ___________________6. Anonymous Philippines vandalizes the Comelec’s Website.
___________________7. Uses code to access operating systems and software.
___________________8. Employees who have access to data, equipment, and the network.
___________________9. Users outside an organization who do not have authorized access
to the network or resources.
___________________10. It is hidden in software that appears to do one thing, and yet
behind the scenes it does another.
___________________11.It is attached to small pieces of computer code, software, or
document.
ACTIVITIES

29. Activity 2.
Sequencing: Rearrange the SMADAV installation steps. Use small letter to indicate
their order of precedence.
_______1. Double click on the file from the desktop
_______2. Click Launch and Finish
_______3. Access http://www.smadav.net/ website and click on Free Download
_______4. Click OK with language selection
_______5. Accept the license agreement and click Next
_______6. Wait till save as window appears. Save the file on the Desktop
_______7. Click Install
_______8. Click Next with Desktop shortcut option
_______9. Click Next on the Welcome Wizard
ACTIVITIES

30. Activity 1: Activity 2:
1. Data 1. c
2. Physical 2. h
3. Worm 3. a
4. Physical/Data 4. d
5. Malicious Threat 5. e
6. Unstructured Attack 6. b
7. Structured Attack 7. g
8. Internal 8. f
9. External 9. e
10. Trojan Horse
11. Virus
Answer Key: