Companion Virus

While it is possible for COM and EXE files to have similar names, it’s also very rare. More often than not, it a sign of this crafty infection. The companion virus typically installs a COM file, or infection, for every executable file available on the hard drive. Systems such as DOS will run COM files before EXE. This allows the infection to run first, slithering its way into the memory and executing all EXE files. Often the companion virus will conceal the additional files by storing them in another directory or assigning hidden attributes. This prevents a basic DIR command from displaying it. This infection is able to hide its COM files while active in the memory, but can also inflict damage from other areas. The companion virus is easily detected with the presence of additional COM files. By viewing a map of what should actually be on the hard drive, a user can locate the infection and safely remove it.