What are Virus & Malicious Code

Malicious code refers to a broad category of programs that can cause damage or undesirable effects to computers or networks. Potential damage can include modifying, destroying or stealing data, gaining or allowing unauthorised access to a system, bringing up unwanted screens, and executing functions that a user never intended.

Examples of malicious code include computer viruses, worms, trojan horses, logic bombs, spyware, adware and backdoor programs. Because they pose a serious threat to software and information processing facilities, users and administrators must take precautions to detect and prevent malicious code outbreaks.

Computer viruses are still the most common form of malicious code. A virus is a program that infects a computer by attaching itself to another program, and propagating itself when that program is executed. Another frequently encountered malicious code is the worm, which is a computer program that can make copies of itself, spreading through connected systems and consuming resources on affected computers or causing other damage.

Some malicious codes, including most viruses, are fragments of programs that cannot exist alone and need to attach themselves to host programs. Other types of malicious code are able to spread and replicate by themselves (such as worms) and are able to propagate from computer to computer across a network.

It should be noted that some malicious programs are able to exhibit the behaviors of more than one type of malicious code. For example, certain programs may be a virus and a trojan horse at the same time.

Growing Risk

The risks posed by malicious code are on the rise, due to fundamental changes in the threats and purposes that malicious code is put to. Instead of just causing a nuisance and being destructive, malicious code attacks are becoming more motivated by financial gain. Attackers are increasingly sophisticated and organised, adopting methods that are similar to traditional software development and business practices.

It has been shown that the amount of time between the discovery of a software vulnerability and attempts to exploit that vulnerability via attacks from new computer viruses/worms is continuously decreasing. In addition, it takes time for anti-virus vendors to develop virus and malicious code definitions, so there is always a chance that your anti-virus software cannot detect newly discovered malicious code in time. Thus, your computer is still vulnerable to virus attack if other security best practices are not put in place.

Your computer system could be infected if:

• a user is lured into installing or opening a malicious attachment / program / plug-in from an un-trusted source or from a spam email

• a user is lured into visiting a malicious website

• the computer is not properly patched, so attackers take advantage and exploit a vulnerability

• the computer is not properly configured, so attackers take advantage and exploit a vulnerability