In this lesson,
we're going to cover replay attacks.
Replay attacks are a type of network-based attack
where valid data transmissions are maliciously
or fraudulently rebroadcasted, repeated or delayed.
This type of attack can be likened to a session hijack
but with a slight difference.
In a session hijack the attacker aims
to modify the information being sent
and received in real time.
However, in a replay attack
the attacker's goal is to intercept the data,
analyze it and decide whether or not to retransmit it later.
To better understand replay attacks,
consider the following example.
Let's pretend that an attacker's able to capture the session
that occurs when you log into your bank
with your username and password.
Now, they could then replay that session
to the bank at a later time
and attempt to log in as you.
This is the basic premise of a replay attack.
And then reuse them to gain unauthorized access
to the system.
For example, if you just logged
into an online shopping website
but the attacker was able
to capture your login session details,
like your username and password,
that attacker could then use these captured credentials
to log into your account anytime they want
and then they can make unauthorized purchases
as if they were you
or even change the account's password
to effectively lock you out of your own account
and try to take over your account fully.
To combat replay attacks it's crucial
to ensure that the websites
and devices use session tokens to uniquely identify
when the authentication session is occurring.
Session tokens are unique pieces of data
that are generated for each session,
and these tokens make it difficult
for an attacker to replay a session.
Multi-factor authentication can also prevent the attacker
from capturing and replaying a login session,
since the attacker would not have the additional piece
of information required for authentication,
such as one-time use passwords that change every 30
to 60 seconds on your smartphone's authenticated app.
By using multi-factor authentication
it becomes nearly impossible for an attacker
to capture and replay a session in order
to gain access to your account.
To minimize the risk of such attacks,
it is highly recommended
that you use the latest security protocols
like Wi-Fi Protected Access 3,
known more commonly as WPA3,
in order to avoid the threat of a replay attack.
So remember, replay attacks involve the fraudulent
or malicious rebroadcasting, repetition or delay
of valid data transmissions.
Credential replay attacks specifically target
a user's logging credentials
to gain unauthorized access to the system.
Mitigation strategies include the use of session tokens
and multi-factor authentication.
Your understanding and awareness of these kinds
of replay attacks is an important step
towards securing your data and protecting yourself
from potential cyber threats.