The Russia–affiliated hacking group Killnet claimed responsibility for a series of cyber–attacks against Japanese companies and 20 websites across four government ministries.
In particular, the country's government is reportedly looking into whether problems to the aforementioned sites were caused by a denial-of-service (DDoS) attack, according to Chief Cabinet Secretary Hirokazu Matsuno.
Japan's digital agency also said its e–Gov administrative portal was experiencing login problems to some services on Wednesday but did not specify the cause.
"We are aware that the [Killnet] hacker group suggested it was behind the attacks, but at the moment, we are still investigating the cause of the failures, including the group's involvement," Matsuno added.
The minister also said that while the government websites could not be accessed on Tuesday evening, they were restored on the same day.
According to Sergey Shykevich, threat intelligence group manager at Check Point Software, however, it is likely that Killnet was behind these attacks.
"Killnet's reasoning for these attacks is due to Japan's support of Ukraine in the ongoing Russia–Ukraine war, as well as a decades–long dispute over the Kuril Islands, which both sides claim sovereignty over," Shykevich told Infosecurity Magazine.
"Disrupting citizens' daily lives with attacks on the government and organizational websites are a surefire means of inconveniencing the government and people."
Further, the cybersecurity expert said organizations in countries being attacked by Killnet must be vigilant of the risks, as the group uses various tools to achieve its goals, including data theft and disruptive attacks.
"An adoption of a prevention–first cybersecurity strategy will help to reduce the likelihood of a cyber–attack, such as preparing a proper offline backup of critical business information, including a recovery plan in the event of a worst–case scenario and segmentation between critical and less critical areas of the corporate network," Shykevich explained.
The alleged attacks against Japanese state websites follow a recent wide–scale attack by Killnet on sites in Italy, Lithuania, Estonia, Poland and Norway.