What runtime is used by most Windows Viruses?

Most开发者_StackOverflow applications created with Microsoft developer tools need some kind of runtime to be installed first. However most viruses never need any kind of runtime to work. Also they also seem to use undocumented core/kernel APIs without have lib files etc.

So what runtime/application do most virus /virus writers use ?

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If the runtime is statically linked in (as opposed to dynamically), then an EXE will be self-contained and you won't need a runtime DLL. However, really, you don't even need a runtime library at all if your code can do everything without calling standard library functions.

As for Windows APIs, in many cases you don't strictly need an import library either -- particularly if you load addresses dynamically via GetProcAddress. Some development tools will even let you link directly against the DLLs (and will generate method stubs or whatever for you). MS tries to ensure that names for documented API calls stay the same between versions. Undocumented functions, not so much...but then, compatibility typically isn't the foremost of concerns anyway when you're deliberately writing malicious software.