For the HLLO version, see AIDS (HLLO).
Not to be confused with AIDS II or OlympicAIDS.

Virus.DOS.Aids is a parasitic virus on DOS.

There are 2 variants:

  • Virus.DOS.Aids.552
  • Virus.DOS.Aids.872


They search for files in current directory, and then write themselves to the end of file.


This is an encrypted memory resident variant, which infects .EXE executable.


This is a non-memory resident variant which infects DOS executable. The virus does not infect every file but it might corrupt them during infection. Files infected by this variant might cause a system hang or memory allocation error when run.

Memory usage

The following table shows the memory usage of the variants.

Variant Memory usage in bytes
Aids.552 1,024
Aids.872 Non-TSR



This variant displays a graphical effect when activated.


When an infected program is run on the 10th day in any month, the virus hangs the system.

Other details

There is a virus having the same alias, the HLLO.AIDS, which is a file overwriting virus written in high level programming language.

Aids.872 contains the internal text string:



  1. Payload simulation of AIDS.552 on