Malware is software deliberately designed to damage, disrupt, gain unauthorised access to, or exfiltrate data from a computer system, encompassing categories such as viruses, worms, trojans, ransomware and spyware. It is typically delivered through an attack vector such as a phishing email, compromised download or vulnerable network service, then executes to achieve goals ranging from data theft to system disruption or extortion. Defence against malware combines endpoint detection, network monitoring, patching and user awareness within a broader cybersecurity programme.