EICAR is the European Institute of Computer Anti-virus Research (http://www.eicar.org).
The EICAR Standard Anti-Virus Test file is a special dummy file which is detected exactly as if it were a virus. It is used to test the correct operation of F-Secure Anti-Virus products; it is also detected by several other antivirus products in a similar manner.
When executed, the EICAR test file will simply display the text "EICAR-STANDARD-ANTIVIRUS-TEST-FILE!" and exit.
How to Create an EICAR file
To create an EICAR test file, use any text editor to create a file with the following single line in it:
Save the file with any name using a COM extension; for example, EICAR.COM. Make sure you save the file in standard MS-DOS ASCII format. Now you can use this file to demonstrate what occurs when a virus is detected.