French navy officials suspect than an infected USB drive is to blame for a Conflicker/Downandup worm infection last month that interfered with the operation of naval logistics systems running Microsoft Windows.

But a French defense ministry spokesperson has denied reports that the worm grounded French navy jets, as claimed in The Telegraph and several French publications.

Citing a French intelligence publication, Intelligence Online, The Telegraph in the United Kingdom reported on Saturday that the Rafale, a plane used in the French navy, had been grounded following a Conflicker worm infection that had spread last month throughout the French nonsecured internal naval network called Intramar. The worm supposedly interfered with French navy's ability to transfer flight data to its planes.

In October, Microsoft issued an out-of-band Security Bulletin, MS08-067, for a vulnerability affecting its Server service. It warned that the vulnerability was "potentially wormable." As Microsoft feared, the vulnerability was wormable and the worm that was released, known as Conflicker or Downandup, and its variants, affected at least 9 million PCs last month.

According to French newspaper Ouest France, the worm's impact on Intramar forced the French navy to "return to conventional means of communication such as telephone, fax, or regular mail" while the infection was mitigated.

Jerome Erulin, a spokesperson for the French navy, said the incident served as an exercise and that it affected communication but resulted in no data loss.

And in keeping with a long tradition of Anglo-Gallic rivalry, Ouest France observed, "The only consolation for the [French] navy is that it is not alone in facing such problems." Its report notes that DefenseTech.org last month said that the U.K. Ministry of Defense had begun investigating what appeared to be a major worm-driven breach affecting over 24 RAF bases and 75% of Royal navy ships."

The Telegraph, in its article on the French security incident, reported the finger-pointing of the French press without comment.

Besides the Conflicker/Downandup worm infection, what other security threats are deemed most serious? InformationWeek polled more than 400 business technology professionals to find out. Download the report here (registration required).