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Japan defense forces used USB drives with China-linked virus: Nikkei investigation

Asia.Nikkei • June 25, 2026

Counterfeit memory sticks infected computers that had access to classified information

The Ground Self-Defense Force used USB drives infected with a virus said to be linked to Chinese hackers. (Photo by Taro Yokosawa)

TOKYO -- Japan's Self-Defense Forces used USB drives containing a China-linked virus on computers with access to classified information for nearly a year, then elected not to disclose the matter even though similar memory sticks were widely available online, a Nikkei investigation has revealed.

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Malware-Infected USB Drives Compromise Japan's Self-Defense Forces Japan's Ground Self-Defense Force unknowingly used counterfeit USB drives embedded with malware linked to Chinese hackers for nearly a year. The incident came to light after personnel noticed abnormal computer performance in February 2025. Investigations revealed that six out of eight tested USB drives contained the same malicious software. These drives were connected to over 50 computers, many of which accessed sensitive command information. The counterfeit drives were procured during disaster relief operations in March 2024 and were found to have significantly lower storage capacity than advertised. The malware was not detected due to antivirus software not scanning USB drives at the time. The incident raises serious concerns about cybersecurity protocols within Japan's defense infrastructure. 7 sources 74

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Japan defense forces used USB drives with China-linked virus: Nikkei investigation

The full story

Extracted Entities

Attack Types (1)

Countries (1)

MITRE ATT&CK (1)