There are “strong indications” that Russia was behind a cyber attack on the Dutch public prosecution department’s internal systems, justice ministry sources have told the AD.

The affected systems contain sensitive information on ongoing police investigations and court cases, as well as personal data on staff. The department has not yet said what, if any, information was accessed.

The first warning came in June, when the National Cyber Security Centre (NCSC) issued an alert about a vulnerability in Citrix software used by the department. However, the weakness was not closed for another seven days, and the prosecution department only took its systems offline on July 17.

That delay gave hackers at least three weeks to access the system, the AD said. The actual breach may have started even earlier if the flaw was exploited before the public warning was issued.

Cybersecurity experts told the AD that hackers linked to both China and Russia have been targeting dozens of organisations, and this now appears to include Dutch institutions.

Russia is considered more likely than China to be interested in the prosecution service’s files due to the MH17 investigation, one expert said.

In 2017, Russia’s intelligence service SRU infiltrated Dutch police systems during the investigation into the downing of flight MH17 by a Russian-backed militia in eastern Ukraine in 2014.

The Dutch military police are also examining possible war crimes committed by Russian forces in Ukraine, which would be another possible motive, Pim Takkenberg of cybersecurity firm Northwave told the paper.

Russian hackers are also suspected of being behind a separate attack on the Dutch police network last September, during which work-related details of tens of thousands of officers were stolen.