What is the cyber kill chain? Everything you need to know

Martin adapted this strategy to defend computer systems against advanced persistent threats (APTs) involving malware, ransomware, Trojans, spoofing, and social engineering methods. Professionals and organizations use this approach to identify and prevent malicious activity and cyberattacks in the future.

The cyber kill chain model employs seven distinct phases to break down the external attack process, allowing cybersecurity professionals to identify and stop attacks at various stages. Let’s see what each of these steps entails.

Reconnaissance

Reconnaissance is the information-gathering phase of the cyber kill chain process, where the attacker investigates potential targets and identifies vulnerabilities. They use search engines, web archives, packet sniffers, port scanners, public cloud services, network mapping, and other web browsing tools and techniques to gather as much information as possible about the victim. Each information gathering method reveals data pieces, bringing the attacker closer to your networks, applications, and databases.

A bad actor may also research third parties related to the target, for example, company employees. Checking their personal details on social media may provide the attacker with the necessary information for a phishing attack. The goal is to identify weaknesses in technology or human behavior that attackers can exploit.

Weaponization

When the attacker gathers information about the victim, they craft one or more attack vectors to exploit the detected vulnerability. These vectors often involve malware, ransomware, or viruses, allowing criminals to intrude on your space and gain unauthorized access to your information. During weaponization, a hacker may also create back doors, allowing them to continue the attack even if system administrators discover and shut down their initial entry point.

When planning and executing a cyberattack, hackers usually consider several factors, including processing power, target vulnerability, cost, traceability of the crime, and time-to-value. They often take the easiest and the least resistant path to your network or application. So, running regular security checks and assessing every potential access point in your network is essential.

Some of the most common methods that attackers use to gain access to a computer or network include poor encryption, system misconfiguration, weak or stolen passwords, remote access tools, relationships between systems or devices, social engineering, zero-day attacks, brute force attacks, malicious code injection (SQL injection), trojans, and many others.

As soon as a hacker gets into your network, they will look for ways to move around, gather as much valuable information as possible, and stay unnoticed for as long as possible. So, consider employing zero-trust security practices, allowing you to verify everything trying to connect to your systems before granting access and controlling malicious activity.

Delivery

In the delivery phase, an attacker transmits the weapon to the target. The specific enforcement of the attack depends on the vulnerability detected in the reconnaissance phase and an attack vector selected in the weaponization step. The attacker usually transmits the attack vector into your systems through email phishing combined with social engineering techniques, drive-by downloads from websites, infected USB drives, or direct network connections.

Hackers can deliver cyberattacks in various ways. For instance, they can make malware act immediately or program cyberattacks to launch after a delay or triggered by a specific user action. Typically, these attacks involve a single intrusion where the attacker enters the system, obtains what they need, and exits. However, sometimes hackers set up malicious programs to stay within your system and continuously monitor and control your activity.

Exploitation

During exploitation, the attacker activates the intended malware or virus to exploit a weakness in the targeted system. Sometimes, these programs employ masking features to hide their malicious activity within the network and remain undetected.

Installation

Once the attacker completes the exploit, they install additional tools or malware to maintain control over the system and ensure persistent access. This could be a backdoor, a remote access trojan, or other forms of malware, allowing attackers to enter and exit the system without the risk of being identified.

Hackers may use rootkits or weak credentials to reenter the system without employing the initial attack vectors. Until these intrusion methods don’t raise suspicion for system administrators, the invasion may be challenging to detect, allowing attackers to wander around internal systems indefinitely.

Command and control (C2)

In the command and control phase, the attacker establishes a method to control the compromised system and exfiltrate sensitive data remotely. The data retrieval process may involve installing ransomware or spyware on the target network, allowing attackers to extract valuable assets. This lets malicious actors move laterally within the system, setting up even more entry points.

If you detect an invasion in the C2 phase, the hackers are already in your system. So, it is crucial to have intrusion detection systems and other security practices in place to detect malicious behavior before it’s too late.

Actions on objectives

Finally, the attacker takes action to achieve their primary objectives. These could include stealing sensitive corporate data or personal information for monetary gain, wiping data and disrupting services, gathering strategic company information, or even preparing for larger security breaches.

In this stage of the kill chain, system administrators must react immediately because the attacker will move as fast as possible to extract sensitive data and gain maximum profit. The sooner a security team detects malicious activity on the network, the lower the potential risk.

While the cyber kill chain is a valuable framework for understanding and combating cybersecurity threats and attack vulnerabilities, it has limitations. First, the model was initially designed to identify external attacks that have already been initiated rather than prevent them. While it focuses on outside threats, it doesn’t recognize insider threats that may come from employees and contractors.

Since the cyber kill chain model was developed in 2011, some of its methods are outdated and susceptible to advanced attacks in 2024. Besides, its static structure and focus on perimeter security presume that attacks always follow the same pattern. However, hackers can sometimes skip or repeat their steps, making it hard to detect an invasion. In addition to all the previously mentioned cons of this framework, it can also be resource-demanding, requiring a significant investment of money, technology, and expertise.

Considering the limitations of the cyber kill chain process, let’s look at the alternatives to the latter. Mitre ATT&CK and unified kill chain solutions offer different methodologies for defending against cyber threats.

• Mitre ATT&CK. Compared to the linear cyber kill chain model, Mitre ATT&CK is more multidimensional and offers a detailed breakdown of attack methods that hackers use in different stages of an invasion. It is usually used for threat modeling, security testing, and improving defense mechanisms.
• Unified kill chain. The unified kill chain is an expansion of the cyber kill chain framework. It merges kill chain and Mitre ATT&CK principles to provide a comprehensive view of a cyberattack. It is more adaptable to sophisticated threats that don’t follow the linear cyber kill chain procedure.

While the cyber kill chain is just a framework designed to break down the process of a cyberattack, it can help organizations enhance their overall cybersecurity posture. It can help them understand how attackers operate, allowing to develop targeted company security strategy. What’s more, knowing the typical stages of a cyberattack allows security teams to identify security gaps, prioritize where to allocate system resources, and improve response strategies.

Although the cyber kill chain is a valuable tool in mitigating cybersecurity risks, organizations should also employ other strategies for full-scale defense:

• Zero trust security. Zero trust is a necessary security tool, which automatically assumes that no user or device inside or outside the network is trustworthy without verification. It requires strict authentication for devices and users entering systems or private parts of a network.
• Regular software updates. Update your software regularly to patch it against known vulnerabilities.
• Intrusion detection system (IDS). Employ an intrusion detection system to monitor incoming and outgoing network traffic.
• Virtual private network (VPN). Use a VPN to secure a connection between remote users and the organization’s network. It will encrypt data transmission over potentially unsecure public networks.
• Security audits. Run regular security assessments to identify potential security gaps.