The EICAR (European Institute for Computer Anti-Virus Research) Test File helps to test performance of anti-virus programs that detect viruses using signatures.
For this purpose, most of the anti-virus software vendors generally use a standard test.com program. This program was designed specially so that users could test reaction of newly-installed anti-virus tools to virus detection without compromising security of their computers. Although the test.com program is not actually a virus, it is treated by the majority of anti-viruses as if it were a virus. On detection of this file, Dr.Web reports the following: EICAR Test File (Not a Virus!). Other anti-virus tools alert users in a similar way.
The test.com program is a 68-byte COM-file that prints the following line on the console when executed: EICAR-STANDARD-ANTIVIRUS-TEST-FILE!
The file test.com contains the following character string only:
To make your own test file with the “virus”, create a new file with this line and save it as test.com.