"The Windows Update team needs to describe in more detail how they are going to fix the problem. Until then, I bet a lot of people will be thinking twice about the security of Windows Update," said Storms.
Users should deploy last Sunday's certificate revocation update as soon as possible, Microsoft has said, to protect themselves from possible copy-cat hackers.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His e-mail address is firstname.lastname@example.org.
Read more about cybercrime and hacking in Computerworld's Cybercrime and Hacking Topic Center.