This is a dangerous memory-resident encrypted parasitic virus. It hooks INT 21h and writes itself to the end of COM and EXE files that are accessed. The EXE files are infected incorrectly, they halt the system being executed. In some cases the virus also hooks INT 14h (COM port), and on some calls (BBS login?) it displays the message:
XXXXXXXX xXXXXXx xXXXXXx XXX XX xXXXXXXx XX XX xXXXXXXx XXXXXXxx
xXx XXxxxXX XXxxxx XXXxxxXX XXxxxxXX XXxx xXX XXxxxxXX XX XXX
xXx XXxxxXX xxxxXX XXXxxxXX XXxxxxXX xXXXXx XXxxxXXX XXXXXX
xXx XX XX xXXXXXXx XX XX XX XXX xXx XX XX XXX xXX
Proudlyy Presentedd by Quantuum
It also contains the string:
[Tasha Yar] by Quantum / VLAD
