Types of Malicious Code

Malicious code can be defined as code that has been developed to perform various harmful activities on a normal computer. Examples of such harmful activity can be actions such as stealing the end users data or personal information, infecting other ma-chines on a network or sending spam through infected machines. There are several categories of malicious code which include but are not limited to viruses, worms, trojan horses and bots. Each of these categories has differing characteristics according to their intended purpose. As we move forward, our aim is to discuss the various techniques we can use for effectively analyzing such malicious code.

Let us discuss the basic definitions of some different types of malicious code:


• Virus: Viruses are simple programs, which are written to change the way the computer works without the permission of its user. A virus cannot infect other PCs on a network until someone executes an infected file.

• Trojan Horse: In the context of computer software, a Trojan horse is a program that unlike a virus, contains or installs a malicious program (sometimes called the payload or 'Trojan') while under the guise of being something else.

• Worms: A computer worm is a self-replicating computer program. It uses the network to send copies of itself to other nodes (computer terminals on the network)
and it may do it without any user intervention.

• Bots: A bot is a malicious program, which receives instructions from its controller and performs operations according those instructions. By their nature, bots will replicate using various techniques like exploiting remote systems, sending e-mails using social engineering and subsequently creating a network of bots which are referred to as botnets. This network of compromised computers can be used to launch Distributed Denial of Service attacks, install malware or perform other nefarious activities. Bots are rising in popularity.