This is a virus detection. Viruses are programs that self-replicate recursively, meaning that infected systems spread the virus to other systems, which then propagate the virus further. While many viruses contain a destructive payload, it's quite common for viruses to do nothing more than spread from one system to another.
This tool is an industry recognized testing file. The name is derived from an organization named EICAR, or European Institute for Computer Anti-Virus Research. The file, and its use, is also described at this website.
The file is comprised of a test string, and is a DOS executable. Running the file should not do anything more than display a message on your screen:
The EICAR.COM test file can be obtained from either EICAR or by copying the text below into NOTEPAD and saving the file as EICAR.COM:
The file should be 68 or 70 bytes in length and is an executable on Intel platforms. If on-access scanning is enabled, the file will be detected during the save process in NOTEPAD.
There is one known attack on the concept of the EICAR test file; please read the description of Bat/Bwg.a@MM for details.
This is not a virus.