Threat intelligence (TI) is intelligence about threats. It is a subset of intelligence cycle management focused on identifying, analyzing, and responding to threats. The goal of threat intelligence is to allow security practitioners to make informed decisions about how to protect their organizations. 

Threat intelligence can be divided into two main categories: strategic and tactical. Strategic threat intelligence is long-term and focuses on the big picture. It is used to help organizations make decisions about where to allocate resources and how to best protect themselves. Tactical threat intelligence is short-term and focuses on specific threats. It is used to help organizations respond to and mitigate specific threats. 

There are four main types of threat intelligence: 

1. Indicators of compromise (IOCs)

2. Vulnerabilities

3. Attacks

4. Actors

IOCs are specific pieces of information that can be used to identify a threat. They can include things like IP addresses, domain names, file hashes, and registry keys. 

Vulnerabilities are weaknesses in systems or software that can be exploited by attackers. They can be found in both public and private databases. 

Attacks are the methods that attackers use to exploit vulnerabilities. They can be divided into three main categories: 

1. Reconnaissance

2. Lateral movement

3. Destruction

Reconnaissance is the first stage of an attack and involves gathering information about the target. Lateral movement is the second stage of an attack and involves moving through the target system to find valuable data. Destruction is the third stage of an attack and involves deleting or corrupting data. 

Actors are the people or groups behind the attacks. They can be divided into three main categories: 

1. Hacktivists

2. Nation-states

3. Organized crime

Hacktivists are motivated by a desire to promote a political or social agenda. Nation-states are motivated by a desire to gain a political or economic advantage. Organized crime is motivated by a desire to make money. 

Threat intelligence can be used to protect organizations in a number of ways. It can be used to identify potential threats, assess the risk of those threats, and develop strategies for mitigating them. It can also be used to monitor the environment for changes that could indicate a new or emerging threat. 

Organizations can use threat intelligence to make their security programs more effective and efficient. By understanding the threats that they face, they can prioritize their resources and focus on the areas that are most at risk. They can also use threat intelligence to develop better detection and response capabilities. 

Threat intelligence is a valuable tool for security practitioners. By understanding the threats that they face, they can make informed decisions about how to best protect their organizations.