Japan's Ministry of Finance announced on Friday that 123 of its computers were found to be infected with Trojans that could be stealing sensitive data.

"The discovery was made when an outside consultancy was preparing to upgrade the Ministry’s 2,000 PCs," Infosecurity reports. "Few specific details have been released, and it is not known whether the infection spread via an e-mail attachment, by drive-by downloading, or by a USB device. There is concern, however, that it had evaded detection by the Ministry’s anti-malware software."

"Information stored on the PCs is suspected to have been stolen over a period of several months," AsiaOne reports. "The ministry has launched an investigation to find the route of the infection and determine what information was stolen. ... The infection is believed to have spread for more than one year. The infected PCs were improperly accessed by servers in Japan, China, the United States and other countries."

"[A finance ministry official] said the computers didn't include any used by senior ministers or bureau heads, and only a handful of them were used by division heads," Total Telecom reports. "'No information pertaining to private individuals' tax information, or confidential defense information was saved on any of the infected computers,' the official said, adding that any possible leaks were likely confined to the users' emails and documents created for meetings. ... The official declined to comment on whether the affected computers had access to any sensitive domestic or international information."