Adri is a Hungarian virus. The virus overwrites the MBR of the first
hard drive after one month of the first infection. The virus infects
EXE files during execution and appends its excrypted virus body to the
end of such files.
It does not display a message when it activates, thus the problem with
the hard disk will be visible after booting the PC next time.
[Analysis: Peter Szor, F-Secure, 1998]