"The Romanian security vendor said its removal tool will delete all versions of Downadup and will not be detected by the virus." .. Uhm well it got detected by /dot.

Whichever language, concentrate on algorithms (data and exectuion flow), terminology and practice. I'd use C.

PS: in which case you shouldn't forget to tell them why "int main(void/int argc,char **argv/char **env) { return EXIT_SUCCESS; }" are the only three ways of doing it right :)
PPS: teach them to indent/format their code consistently, I want to be able to read their crap when they'll get employed in the industry. Pyhon would inherently help here.