IT security, or information technology security, involves protecting computer systems, networks, and data from unauthorized access, attacks, damage, or theft. It encompasses a wide range of practices, tools, and methodologies designed to safeguard the integrity, confidentiality, and availability of information.

At its core, IT security seeks to prevent cyber threats, which can range from malware, viruses, and phishing attacks to more sophisticated threats like advanced persistent threats (APTs) and ransomware. Cybercriminals, hackers, and malicious insiders are common sources of these threats, often aiming to exploit vulnerabilities in systems for financial gain, espionage, or simply to cause disruption.

A key component of IT security is risk management, which involves identifying potential threats and vulnerabilities in a system and then implementing measures to mitigate these risks. This might include the deployment of firewalls, antivirus software, intrusion detection systems, and encryption techniques. Additionally, security policies and procedures are critical in ensuring that users within an organization follow best practices, such as using strong passwords, updating software regularly, and being vigilant about phishing attempts.