A countermeasure is an action, process, device, or system that can prevent, or mitigate the effects of, threats to a computer, server or network. In this context, a threat is a potential or actual adverse event that may be malicious or incidental, and that can compromise the assets of an enterprise or the integrity of a computer or network.
Countermeasures can take the form of software, hardware and modes of behavior. Software countermeasures include:
- personal firewalls
- application firewalls
- anti-virus software
- pop-up blockers
- spyware detection/removal programs.
- biometric authentication systems
- physical restriction of access to computers and peripherals
- intrusion detectors
- frequent deletion of stored cookies and temporary files from Web browsers
- regular scanning for viruses and other malware
- regular installation of updates and patches for operating systems
- refusing to click on links that appear within e-mail messages
- refraining from opening e-mail messages and attachments from unknown senders
- staying away from questionable Web sites
- regularly backing up data on external media.
In military applications, a countermeasure is a system or strategy intended to prevent an enemy from compromising a target. This can be done by shielding, concealing or moving the target, creating decoys or otherwise confusing the enemy.