Man-in-the-middle attacks in Cybersecurity - Step-by-Step Execution

Concept Flow - Man-in-the-middle attacks

User sends message

↓

Attacker intercepts message

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Attacker reads or alters message

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Attacker forwards message to receiver

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Receiver gets message, unaware of attack

The flow shows how an attacker secretly intercepts and possibly changes messages between two parties without their knowledge.

Execution Sample

Cybersecurity

User -> Attacker -> Receiver
Attacker intercepts and modifies message
Receiver receives altered message

This shows the path of a message being intercepted and changed by an attacker before reaching the receiver.

Analysis Table

Step	Action	Message Content	Attacker's Role	Receiver's View
1	User sends message	"Hello"	No action yet	No message received
2	Attacker intercepts message	Hello	Intercepts original message	No message received
3	Attacker modifies message	"Hello, friend"	Changes message content	No message received
4	Attacker forwards message	"Hello, friend"	Sends altered message	Receives "Hello, friend"
5	Receiver replies	"Hi!"	No action	No reply sent to user yet
6	Attacker reads reply	"Hi!"	Reads reply	No reply sent to user yet
7	Attacker forwards reply	"Hi!"	Sends reply to user	Message delivered
8	User receives reply	"Hi!"	No action	Receives reply

💡 Communication ends with both parties unaware of the attacker’s presence.

State Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	After Step 7	Final
Message Content	Hello	Hello	Hello, friend	Hello, friend	Hi!	Hi!
Attacker Role	null	Intercepts	Modifies	Forwards	Forwards	null
Receiver View	No message	No message	No message	Hello, friend	Hello, friend	Hi!

Key Insights - 3 Insights

Why does the receiver not know the message was changed?

Because the attacker forwards the altered message as if it came directly from the user, shown in step 4 of the execution_table.

How can the attacker read the reply without the user noticing?

The attacker intercepts and reads the reply before forwarding it to the user, as shown in steps 5 to 7 in the execution_table.

Is the user aware of the attacker’s presence during communication?

No, the user receives messages normally without knowing they were intercepted, as shown in step 8.

Visual Quiz - 3 Questions

Look at the execution_table, what message content does the receiver get at step 4?

A "Hello"

B "Hello, friend"

C "Hi!"

D "Hello, attacker"

💡 Hint

Check the 'Receiver's View' column at step 4 in the execution_table.

At which step does the attacker modify the message?

A Step 2

B Step 5

C Step 3

D Step 7

💡 Hint

Look at the 'Attacker's Role' and 'Action' columns in the execution_table.

If the attacker did not forward the reply to the user, what would happen?

A User would not get any reply

B User would receive the reply anyway

C Receiver would get the reply twice

D Attacker would be detected immediately

💡 Hint

Refer to the flow of messages in the execution_table steps 5 to 8.

Concept Snapshot

Man-in-the-middle attack:
- Attacker secretly intercepts communication
- Can read or change messages
- Both parties unaware of attacker
- Messages pass through attacker
- Common in unsecured networks

Full Transcript

A man-in-the-middle attack happens when an attacker secretly intercepts messages between two people communicating. The attacker can read or change the messages before sending them on. The user and receiver think they are talking directly, but the attacker is in the middle. This attack works because the attacker forwards messages so both sides do not notice anything wrong. The attacker can also intercept replies and forward them. This makes the communication unsafe without either party knowing.