This active content allows information servers to customise the presentation of their information, but also provides a mechanism to attack systems running a client browser. Mobile malware may arrive at a site through active content such as JavaScript, Java Applets and ActiveX controls. Refer to Handbook 10 Web Security for further details. The Internet is constantly being flooded with information about computer viruses and trojans. While these hoaxes do not infect systems, they are time consuming and costly to handle.
Chain letters are an irritation rather than a major problem.
They can be a way of distributing viruses and trojans. The impact of an infection of malicious code is as varied as any function that can be performed using a programming technique, eg. System flooding, system shutdown, deletion of data, data capture, data transfer etc. Malicious code can impact on one or all aspects of the security requirements ie. Confidentiality, availability and integrity.