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5 phases of a cyber attack: The attacker’s view

Noora Hyvärinen

05.07.17 3 min. read


Cyber security is not something you do once and then you’re done. It is a continuous process that should be part of everything you do. However, no one has the resources to do everything perfectly. Thus, your goal should be constant improvement.

Improving starts with understanding the risks and the threat landscape. This means understanding your adversaries, their objectives, and how they carry out their attacks.

Let’s imagine a case where a company has been hit by a ransomware outbreak. The company is actually dealing with a financially motivated targeted attack, but ransomware is being used as a cover to hide the more targeted activities. The real target is the sensitive customer data.

So, what happens in each phase of the attack?

cyber attack, data breach

Phase 1: Recon

Timeline: months before detection

The attacker’s first goal is to identify potential targets for their mission. Attackers are often motivated by financial gain, access to sensitive information or damage to brand.

The attacker may collect information about the company from LinkedIn and the corporate website, map the supply chain, get building blueprints, information on security systems and available entry points. They may even visit the company building, an event or call the secretary. The attacker might set up a fake company, register domains and create fake profiles for social engineering purposes.

Once the attacker determines what defenses are in place, they choose their weapon. The selected vector is often impossible to prevent or detect. It can be a zero-day exploit, a spear-phishing campaign or bribing an employee. Usually there is a minimal business impact.

Finally, the attacker is ready to plan an avenue of attack.

data breach, cyber attack, spearphishing


Phase 2: Intrusion and presence

Timeline: months before detection

At the second phase of a cyber-attack, the attacker seeks to breach the corporate perimeter and gain a persistent foothold in the environment.

They may have spear-phished the company to gain credentials, used valid credentials to access the corporate infrastructure and downloaded more tools to access the environment. This is virtually untraceable.

It is very typical that the targeted organization is unable to detect or respond to the attack. Even if detected, it is impossible to deduce that our organization was the ultimate target. In practice, the attacker is always successful.

The initial intrusion is expanded to persistent, long-term, remote access to the company’s environment.

data breach, cyber attack, password


Phase 3: Lateral movement

Timeline: months or weeks before detection

Once the attacker has established a connection to the internal network, they seek to compromise additional systems and user accounts. Their goal is to expand the foothold and identify the systems housing the target data.

The attacker searches file servers to locate password files and other sensitive data, and maps the network to identify the target environment.

The attacker is often impersonating an authorized user. Therefore it is very difficult to spot the intruder in this phase.

data breach, attackers view, red team


Phase 4: Privilege escalation

Timeline: weeks or days before detection

The attacker seeks to identify and gain the necessary level of privilege to achieve their objectives. They have control over access channels and credentials acquired in the previous phases.

Finally the attacker gains access to the target data. Mail servers, document management systems and customer data are compromised.

data breach, attackers view, keylogger


Phase 5: Complete mission

Timeline: day 0

The attacker reaches the final stage of their mission. They exfiltrate the customer data they were after, corrupt critical systems and disrupt business operations. Then they destroy all evidence with ransomware.

The cost to the company rises exponentially if the attack is not defeated.

In this example the target was reached before detection. This is typical. Data breaches are extremely difficult to detect, because attackers use common tools and legitimate credentials.

That’s why you need to stay alert at all times. With cyber security, you are never done.

This fictional example is based on experience from real-life cases and experience of our ethical hackers. F-Secure Red Team test is an eye-opening exercise, where the defensive capabilities of companies are tested using the same model the real hackers use.

Check out this video about red teaming:

Noora Hyvärinen

05.07.17 3 min. read


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