Virus.DOS.HLLO.187Killa is a very dangerous file overwriting virus on DOS, written in C++.


When the virus is run, it overwrites the first uninfected EXE executable file in current directory, and overwrites the content of C:\CONFIG.SYS with the string:


The modified CONFIG will have only 8 bytes long. This makes all configuration to lost and some programs to fail on initialization (see screenshot).

After that, it outputs the message:

Out of memory error

This virus uses file replacement overwriting technique. Any file overwritten by the virus will have a size of 48,117 bytes, no matter the size of the original program is larger or smaller than the virus.

This virus contains a bug, if there is no EXE file in the same directory except itself to infect, running it would result a system crash by accessing invalid sector of the disk.

Advanced details

This virus does not stay memory resident after execution.

MD5 hash:


Other details

Most of the code in the virus' binary is built by the compiler and they are useless as they are reserved and have no effect, the actual size of the virus is not larger than 32KB.

See also