8. Sasser – $500 Million
Sasser was developed by an 18 years old student from German in response to Microsoft’s $250,000 bounty for the person behind it. Infected machines usually have Win.log file in the root directory of drive C:. However, the most distinguishable symptom is a shutdown timer that appears when LSASS.exe crashes. During the peak of its attacks, Sasser successfully delayed some trans-Atlantic flights and blocked satellite communications. Some Scandinavian banks also came to a complete halt for a few days.