Virus.DOS.Bad.389 is a memory resident parasitic DOS virus.


When the virus is loaded into memory, it hooks INT 21h to infect any DOS executable that is run. The timestamp of the infected file will be changed to the time of infection.

Memory usage

The exact memory usage is 624 bytes.


After system starts up, the virus outputs a message without running the host program by the time the first infected program is run:

Bad command or file name

The user may run the program normally afterwards since it shows once only in every section.

Other details

The virus contains the internal text strings:

Bad command or file name





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