How does Windows Defender protect against viruses?

Windows Defender, formerly known as Microsoft Security Essentials, is an antivirus software suite developed by Microsoft for Windows PCs. It serves as one of the primary security features provided by Microsoft, combining traditional signature-based antivirus detection and heuristics scans with a cloud-based scanning system.

At a foundational level, Windows Defender uses signatures to detect known viruses and malware. These are all built-in to the software and are updated periodically to ensure that the latest threats are covered. The signatures are created using methods such as reverse engineering, which involves analyzing existing malicious code in search of clues to its behavior. This helps to make sure that the definitions are up-to-date and cover the latest threats.

When a computer is connected to the internet, Windows Defender can automatically initiate a scan that checks the computer’s memory and hard drive for any potential threats. It will also look for suspicious files or processes that may be indicators of malicious activity. If a threat is identified, the antivirus will alert the user and offer one of several response options. These range from deleting the malicious file to moving it to a quarantined area of the computer’s hard drive, where it can be studied further.

In addition to signature and heuristic-based scans, Windows Defender also offers protection against online threats through the use of cloud-based scanning. When a computer connects to the internet, Windows Defender transmits data about the system to Microsoft’s cloud servers, which then compare the information to a database of known virus signatures. If the signature matches a known virus, the antivirus can identify the threat and take preventive measures before it has the opportunity to infect the computer.

Finally, Windows Defender also offers real-time protection against online threats. As soon as the antivirus detects a potential threat, it will alert the user and take the appropriate action to protect the computer. This includes blocking access to malicious websites, preventing downloads of harmful files, and alerting the user if a file or program is running that may contain malicious code.

In sum, Windows Defender offers comprehensive protection against viruses and other forms of malware for Windows computers. It combines signature-based detection, heuristic scanning, and cloud-based scanning to ensure that the latest threats are quickly identified and neutralized. Furthermore, its real-time protection feature allows it to take action before a virus has the chance to do significant damage to the computer.