Malware is the collective name for a number of malicious software variants, including viruses, worm, Trojan and Adware. Shorthand for malicious software, malware typically consists of code developed by cyber attackers, designed to cause extensive damage to data and systems or to gain unauthorized access. The exponential growth and complexity of malware is a big problem for the computer and network security. In the past decade, there has been a tremendous increase in the dependency on the computer systems. Almost every task ranging from daily life activities to business activities have been automated. Two research communities are working in parallel towards their objectives. One is developing the malicious software and second is developing defensive software to protect the systems from malware attacks.