Malicious code is the kind of harmful computer code or web script designed to create system vulnerabilities leading to back doors, security breaches, information and data theft, and other potential damages to files and computing systems. It's a type of threat that may not be blocked by antivirus software on its own. According to Kaspersky Lab, not all antivirus protection can treat certain infections caused by malicious code, which is different from malware. Malware specifically refers to malicious software, but malicious code includes website scripts that can exploit vulnerabilities in order to upload malware.
It is an auto-executable application that can activate itself and take on various forms, including Java Applets, ActiveX controls, pushed content, plug-ins, scripting languages or other programming languages that are designed to enhance Web pages and email.
The code gives a cybercriminal unauthorized remote access to the attacked system — called an application back door — which then exposes sensitive company data. By unleashing it, cybercriminals can even wipe out a computer's data or install spyware. These threats can reach a high level: The U.S. Government Accountability Office has even warned about the threat of malicious code against national security.
Scripts, worms and viruses can harm your computer by finding entry points that lead to your precious data. Visiting infected websites or clicking on a bad email link or attachment are major gateways for malicious code to sneak its way into your system. Antivirus software that features automatic updates, malware removal capabilities, Web-browsing security and the capability to detect all types of infections are the best defense.