Fools' Experiments — Edward M. Lerner

We are not alone, and it's our own damn fault ... Something demonic is stalking the brightest men and women in the computer industry. It attacks without warning or mercy, leaving its prey insane, comatose--or dead.
Something far nastier than any virus, worm, or Trojan horse program is being evolved in laboratory confinement by well-intentioned but misguided researchers. When their artificial life-form escapes onto the Internet, no conventional defense against malicious software can begin to compete. As disasters multiply, computer scientist Doug Carey knows that unconventional measures may be civilization's last hope.
And that any artificial life-form learns very fast ….