- Hi. My name's Jenny Martin

and I'm the Director of Cybersecurity

Investigations at Symantec.

Today cybercrime causes huge problems

for society.

Personally, financially, and even

in matters of national security.

Just in the last few years,

hundreds of millions
of credit card numbers

have been stolen.

Tens of millions of
social security numbers

and health care records were compromised.

Even nuclear centrifuges have been hacked

and unmanned aerial
drones have been hijacked.

This is all done by
exploiting vulnerabilities

in hardware and software.

Or more often by taking advantage of

unintentional decisions made by the people

using the software.

The people committing these cybercrimes

don't fit a single profile or motivation.

It could be anyone from an
international terrorist,

to a teenager competing
for bragging rights.

Today, the largest countries not only

have a regular army, but also have

a well-armed cyber army.

In fact, the next world war may not

be fought with traditional weapons

but with computers, used to shut down

national water supplies, energy grids,

and transportation systems.

- Hi. My name is Parisa

and I'm Google's Security Princess.

I've worked on a lot of
different Google products

in a lot of different ways
to try and make our software

as secure as possible.

Now let's take a look at how cybercrime

works under the hood.

We'll learn about software viruses,

denial-of-service attacks,
and phishing scams.

In biology in life, a virus is an organism

that is spread by coughing, sneezing,

or physical contact.

Viruses work by infecting cells,

injecting their genetic material

and using those cells to replicate.

They can make people really sick

and then spread to other people.

A computer virus works a bit similarly.

A virus is an executable program

that gets installed,
usually unintentionally,

and harms a user and their computer.

It's also possible for
a virus to spread itself

to other computers.

Now how does a virus get on your computer

in the first place?

There are couple ways an attacker

can infect someone's computer.

They might lure a victim
into installing a program

with deception about
the program's purpose.

So for example, a lot
of viruses are disguised

as security updates.

It's also possible that the
software on your computer

has a vulnerability.

So an attacker can install itself

without even needing explicit permission.

Once a virus in on your computer

it can steal or delete any of your files,

control other programs,
or even allow someone else

to remotely control your computer.

Using computer viruses,
hackers can take over

millions of computers worldwide.

And then use them as a digital army,

otherwise known as a botnet,

to attack and take down websites.

This kind of attack is called

a distributed denial-of-service.

A denial-of-service is when hackers

overwhelm a website
with too many requests.

We call it a distributed denial-of-service

when the attack comes from many computers

all at once.

Most websites are ready to respond

to millions of requests a day,

but if you hit them with
billions or trillions

of requests coming from different places,

the computers are overloaded
and stop responding.

- Another trick used by cybercriminals

is to send large amounts of spam email

in an attempt to trick people

into sharing sensitive
personal information.

This is called a phishing scam.

A phishing scam is when you get

what seems like a trustworthy email

asking you to login to your account,

but clicking the email
takes you to a fake website.

If you login anyway, you've been tricked

into giving your password away.

Hackers can then use
your login credentials

to access your real accounts

to steal information, or maybe even

to steal your money.

Fortunately there are many companies,

laws, and government organizations

working to make the internet safer.

But these efforts are not enough.

You may think when a
computer system gets hacked,

the problem was the security design,

or the software.

90% of the time a system
gets hacked however,

it's not because of a security bug,

but because of a simple
mistake made by a human.

- It turns out there are
steps we can all take

to protect ourselves.

Often, your actions not only impact

the security of your
own data and computer,

but the security of everyone

at your school, workplace, and home.

With billions or trillions
of dollars at stake,

cybercriminals get smarter each year,

and we all need to keep up.