Isso não é muito para continuar (provavelmente há muitas histórias que correspondem à sua descrição), mas dado o prazo, minha aposta seria A adolescência da P-1 (1977) por Thomas Joseph Ryan.
Do artigo da Wikipédia:
After reading a Scientific American article on game theory outlining how to teach matchboxes to play tic-tac-toe, he becomes interested in using artificial intelligence techniques to crack systems. After manually cracking the university's 360, he sets aside a portion of memory to experiment in, calling it "P-1", suitably cryptic so operators would not notice it. He then uses this area of memory as an experimental scratchpad to develop a program known as The System. The System follows any telecommunications links it can find to other computers, attempting to compromise them in the same way, and remembering failed attempts to tune future attacks. If successful, The System sets up another P-1 on that computer, and injects itself and everything it has learned so far into it.