A network attack that is simple in concept,
but can cause a lot of damage is a DNS Cache Poisoning attack.
You probably remember from the bits and bytes of computer networking course,
that DNS works by getting information about
IP addresses and names to make it easier for you to find a website.
A DNS Cache Poisoning attack works by tricking a DNS server into
accepting a fake DNS record that will point you to a compromised DNS server.
It then feeds you fake DNS addresses when you try to access legitimate websites.
Not only that, DNS Cache Poisoning can spread to other networks too.
If other DNS servers are getting their DNS information from a compromised server,
they'll serve those bad DNS entries to other hosts.
Several years ago, there was a large scale DNS Cache Poisoning attack in Brazil.
It appeared that attackers managed to poison the DNS cache of some local ISPs,
by inserting fake DNS records for
various popular websites like Google, Gmail, or Hotmail.
When someone attempted to visit one of those sites,
they were served a fake DNS record and were
sent to a server that the attacker controlled,
which hosted a small java applet.
The user would then be tricked into installing the applet,
which was actually a malicious banking trojan designed to steal banking credentials.
This is an example of the real world damage DNS Cache Poisoning attacks can pose.
You can learn more about it in the next supplementary reading.
A man-in-the-middle attack, is an attack that places the attacker in
the middle of two hosts that think they're communicating directly with each other.
It's clearly a name that needs some updating,
men aren't the only hackers out there.
The attack will monitor the information going to and from these hosts,
and potentially modify it in transit.
A common man-in-the-middle attack is a session hijacking or cookie hijacking.
Let's say you log into a website and forget to log out.
Now, you've already authenticated yourself to the website and
generated a session token that grants you access to that website.
If someone was performing a session hijacking,
they could steal that token and impersonate you on the website,
and no one wants that.
This is another reason to think about the CIA's of security,
you always want to make sure that the data that you are sending
or receiving has integrity and isn't being tampered with.
Another way a man-in-the-middle attack can be established is a rogue access point attack.
A rogue AP is an access point that is
installed on the network without the network administrator's knowledge.
Sometimes, in corporate environments,
someone may plug a router into their corporate network to
create a simple wireless network. Innocent enough, right?
Wrong. This can actually be pretty dangerous,
and could grant unauthorized access to an authorized secure network.
Instead of an attacker having to gain access to
a network by plugging directly into a network port,
they can just stand outside the building and hop onto this wireless network.
A final man-in-the-middle method will cover is called an evil twin.
It's similar to the rogue AP example but has a small but important difference.
The premise of an evil twin attack is for you
to connect to a network that is identical to yours.
This identical network is our networks evil twin and is controlled by our attacker.
Once we connect to it,
they will be able to monitor our traffic.
I wonder if Fred Weasley ever did this to George,
probably not, they were wizards.
They could just magic their way out of problems. Must be nice.