In IT systems, multiple countermeasures may be applied for enhanced security. Protective countermeasures may be in the form of hardware or software.

Examples include:

• Routers: Mask Internet Protocol (IP) addresses
• Anti-virus and anti-spyware applications: Protect against malicious software (malware), including viruses, Trojans and adware
• Behavioral techniques: Applied by users to deter threats, such as suspicious email attachments
• Firewalls: Facilitate authorized network access
• Intrusion detection systems (IDS): Prevent and/or block unauthorized system access
• Physical security (especially in enterprises): Prevents hacking and network subterfuge