As we know that all these three are type of unwanted computer programs/code that results in slowness or completely stops the execution of our program due to which system behaves unexpectedly in nature.
On the basis of features and type of these program/code, we can distinguish between Virus, Worm and Trojan Horse as follows −
|Sr. No.||Key||Virus||Worm||Trojan Horse|
|1||Definition||Virus could be defined as a computer program or software which get installed either by itself or unknowingly by the user and get connect itself to another software/program to perform unexpected task when actual program going to run by the system.||On other hand Worm could be defined as a computer program like virus but it does not get connected with other system program but get more in number and executes itself to make system slow and degrades its performance.||On other hand Trojan Horse is a hidden piece of code that primarily steals the sensitive information/data from user system and made export to other outer location over the network.|
|2||Remote Accessible||Virus can't be get controlled by remote as they get install over the target machine itself or unknowingly by the user.||On other hand Worms can be controlled by the remote as it may create a back door on the host.||Also Trojan Horse can be controlled by the remote as like of worms over the network.|
|3||Repetition||Virus could not get repeated by itself just like worm also the spreading rate of viruses are moderate.||On other hand Worm get repeated by itself in the system and spreading rate of Worms are faster than virus and Trojan horse.||Spreading rate of Trojan Horse is slow in comparison of both virus and Worms.|
|4||Objective||Virus has main objective of modify or delete the data of system.||On other hand objective of Worms is to degrade the system performance and slow the system by consuming the system resources.||Just like in the tale, the Trojan horse virus disguises as a normal program and steals the vital information.|