International Journal of Advanced Research in Computer Science and Software Engineering (IJARCSSE)
A common technique that virus writers use to avoid detection is to enable the virus to change itself by having some kind of self-modifying code. Metamorphic viruses, which are arguably the most dangerous of all, change their structure or signature each time they propagate without changing the functionality of the virus. Metamorphism provides one of the strong known methods for evading malware detection. If the virus is metamorphic it could potentially be difficult to find a single signature that will consistently be found in every version of a metamorphic virus.