Authorities in the Netherlands have arrested the co-owners of two related Internet hosting companies for operating IT infrastructure used by Russia to carry out cyberattacks, influence operations and disinformation campaigns inside the European Union. The two men were the focus of a 2025 KrebsOnSecurity story about how their hosting companies had assumed control over the technical infrastructure of Stark Industries Solutions, an Internet service provider sanctioned last year by the EU as a frequent staging ground for cyber mischief from Russia’s intelligence agencies.

An investigator with the Tax Intelligence and Investigation Service (FIOD), the Dutch financial crimes agency, during the raid. Image: FIOD.

The Dutch daily news outlet de Volkskrant reports that the Dutch financial crime agency FIOD on May 18 arrested a 57-year-old from Amsterdam and a 39-year-old from The Hague, charging them with violating sanctions law by directly or indirectly making economic resources available to EU-sanctioned entities.

The Dutch investigation focuses on Stark Industries, a sprawling hosting provider that materialized just two weeks before Russia invaded Ukraine. As detailed in this May 2024 deep-dive, Stark quickly became the source of massive distributed denial-of-service (DDoS) attacks against European targets, and emerged as a top supplier of proxy and anonymity services that showed up time and again in cyberattacks linked to Russia-backed hacking groups.

That report identified two Moldovan brothers — Ivan and Yuri Neculiti and their company PQHosting — who were providing one of Stark’s two main conduits to the larger Internet. In May 2025, the EU sanctioned PQHosting and the Neculiti brothers for aiding Russia’s hybrid warfare efforts. But as KrebsOnSecurity observed in September 2025, those sanctions failed to target Stark’s remaining connection to the Internet — an Internet service provider based in the Netherlands called MIRhosting.

MIRhosting is operated by Andrey Nesterenko, a 39-year-old Russian native who runs the business out of the Netherlands.  News that PQHosting and the Neculiti brothers were about to be sanctioned by the EU leaked in the media nearly two weeks before the sanctions were announced last year. During that time, the Stark network assets were transferred from PQHosting to a new entity called the[.]hosting, under the control of the Dutch entity WorkTitans BV.

And as our September 2025 report showed, WorkTitans was controlled by Nesterenko and a 57-year-old from Amsterdam named Youssef Zinad. On top of that, WorkTitans was getting connectivity to the larger Internet solely through MIRhosting, where Zinad had worked previously.

On May 18, Dutch financial crime investigators arrested Nesterenko and Zinad, and searched three businesses in Enschede and Almere and two data centers in Dronten and Schiphol-Rijk. A statement from the Dutch authorities said they also seized laptops, telephones and more than 800 servers.

A message to the-hosting customers immediately after 800 of its servers were seized by Dutch authorities. The message says that unfortunately data stored on the server has been lost and cannot be recovered.

De Volkskrant said it reviewed data showing WorkTitans and MIRhosting were the most-used networks in pro-Russian attacks on Danish government bodies between November 13 and 19, 2025, the week of Denmark’s municipal elections.

The publication wrote that prior to Nesterenko’s arrest, the MIRhosting founder denied that he knew his servers had been misused by pro-Russian cybercriminals. “He said he had ended all services with the Neculiti brothers when the EU sanctions came into force in May 2025,” and the he “reserved all rights to take action against ‘harmful and incorrect publications,” de Volkskrant wrote.

MIRhosting released a statement saying it has initiated an internal investigation into the alleged facts concerning the elections in Denmark, and that it has temporarily paused services to WorkTitans as a precautionary measure while the matter is being reviewed further.

“Based on our preliminary findings, there are no indications that the services over which we exercise control were actually used to influence the Danish elections,” the statement reads. “No anomalies or spikes were observed in our network traffic during the period mentioned in the publication; had large-scale DDoS attacks occurred, such activity would have been evident. Furthermore, prior to the media publication, we had not received any complaints, abuse reports, or official requests regarding suspicious activities or misuse of our network. Meanwhile, our regular operational activities continue, and our service to our other clients remains fully intact.”

Born in Nizhny Novgorod, Russia, Mr. Nesterenko grew up as a piano prodigy who performed publicly at a young age. In 2004, Nesterenko founded MIRhosting’s parent Innovation IT Solutions Corp., which has the notable distinction of being the company responsible for hosting stopgeorgia[.]ru, a hacktivist website for organizing cyberattacks against Georgia that appeared at the same time Russian forces invaded the former Soviet nation in 2008. That conflict was thought to be the first war ever fought in which a notable cyberattack and an actual military engagement happened simultaneously.

Responding to questions shared via email, Nesterenko said MIRhosting does not support cybercrime, sanctions evasion, or illegal activity, and that the allegations and arrest by Dutch authorities have been extremely harmful to him and his company.

“The transition to the.hosting was not intended to evade sanctions,” Nesterenko wrote. “The hardware and customer portfolio had already been transferred to WorkTitans before the sanctions appeared. Closing or damaging a legitimate Dutch infrastructure company will not stop cybercrime, but it will harm many people who have done nothing wrong.”

Far less is public about the 57-year-old Zinad, who reportedly has been keeping a low profile since our story last year. De Volkskrant reported that Zinad blocked access to his LinkedIn account, had gone months without responding to emails, WhatsApp messages and phone calls, and told a colleague that illness was forcing him to lead a somewhat more reclusive life.

Mr. Zinad’s now-defunct LinkedIn profile. It was full of posts for MIRhosting’s services.

Mr. Nesterenko claims Zinad was never an employee of MIRhosting.

“He helped me and MIRhosting with certain business tasks under a normal business-to-business arrangement between companies,” Nesterenko explained.

However, in previous emails to KrebsOnSecurity, Nesterenko carbon copied Mr. Zinad (who had a @mirhosting.com email), explaining that he was part of the company’s legal team. Also, the Dutch website stagemarkt[.]nl lists Youssef Zinad as an official contact for MIRhosting’s offices in Almere.

Mr. Zinad has never responded to requests for comment. Nor did de Volkskrant have any luck tracking him down. The publication said it repeatedly asked Mr. Zinad (referred to here as simply “Z”), but he reportedly avoided every form of contact.

“‘I am unavailable but will respond to your message as soon as possible,’ reads an automated reply on WhatsApp on 2 October 2025,” de Volkskrant reported. “It is the only response de Volkskrant would receive in months. He did not pick up his phone and did not call back. When an acquaintance asked him via LinkedIn to contact the reporter, he blocked access to his LinkedIn page. At an address in Almere where Z.’s personal limited company is registered, no one was present in April. The corner house’s blinds were drawn, and a pile of rubbish bags lay outside next to a container, as if someone had recently left. A neighbour said he knew the man but did not know where he was staying. Z. was later arrested at a residence in Amsterdam.”

Until this past weekend, a contractor for the Cybersecurity & Infrastructure Security Agency (CISA) maintained a public GitHub repository that exposed credentials to several highly privileged AWS GovCloud accounts and a large number of internal CISA systems. Security experts said the public archive included files detailing how CISA builds, tests and deploys software internally, and that it represents one of the most egregious government data leaks in recent history.

On May 15, KrebsOnSecurity heard from Guillaume Valadon, a researcher with the security firm GitGuardian. Valadon’s company constantly scans public code repositories at GitHub and elsewhere for exposed secrets, automatically alerting the offending accounts of any apparent sensitive data exposures. Valadon said he reached out because the owner in this case wasn’t responding and the information exposed was highly sensitive.

A redacted screenshot of the now-defunct “Private CISA” repository maintained by a CISA contractor.

The GitHub repository that Valadon flagged was named “Private-CISA,” and it harbored a vast number of internal CISA/DHS credentials and files, including cloud keys, tokens, plaintext passwords, logs and other sensitive CISA assets.

Valadon said the exposed CISA credentials represent a textbook example of poor security hygiene, noting that the commit logs in the offending GitHub account show that the CISA administrator disabled the default setting in GitHub that blocks users from publishing SSH keys or other secrets in public code repositories.

“Passwords stored in plain text in a csv, backups in git, explicit commands to disable GitHub secrets detection feature,” Valadon wrote in an email. “I honestly believed that it was all fake before analyzing the content deeper. This is indeed the worst leak that I’ve witnessed in my career. It is obviously an individual’s mistake, but I believe that it might reveal internal practices.”

One of the exposed files, titled “importantAWStokens,” included the administrative credentials to three Amazon AWS GovCloud servers. Another file exposed in their public GitHub repository — “AWS-Workspace-Firefox-Passwords.csv” — listed plaintext usernames and passwords for dozens of internal CISA systems. According to Caturegli, those systems included one called “LZ-DSO,” which appears short for “Landing Zone DevSecOps,” the agency’s secure code development environment.

Philippe Caturegli, founder of the security consultancy Seralys, said he tested the AWS keys only to see whether they were still valid and to determine which internal systems the exposed accounts could access. Caturegli said the GitHub account that exposed the CISA secrets exhibits a pattern consistent with an individual operator using the repository as a working scratchpad or synchronization mechanism rather than a curated project repository.

“The use of both a CISA-associated email address and a personal email address suggests the repository may have been used across differently configured environments,” Caturegli observed. “The available Git metadata alone does not prove which endpoint or device was used.”

The Private CISA GitHub repo exposed dozens of plaintext credentials for important CISA GovCloud resources.

Caturegli said he validated that the exposed credentials could authenticate to three AWS GovCloud accounts at a high privilege level. He said the archive also includes plain text credentials to CISA’s internal “artifactory” — essentially a repository of all the code packages they are using to build software — and that this would represent a juicy target for malicious attackers looking for ways to maintain a persistent foothold in CISA systems.

“That would be a prime place to move laterally,” he said. “Backdoor in some software packages, and every time they build something new they deploy your backdoor left and right.”

In response to questions, a spokesperson for CISA said the agency is aware of the reported exposure and is continuing to investigate the situation.

“Currently, there is no indication that any sensitive data was compromised as a result of this incident,” the CISA spokesperson wrote. “While we hold our team members to the highest standards of integrity and operational awareness, we are working to ensure additional safeguards are implemented to prevent future occurrences.”

A review of the GitHub account and its exposed passwords show the “Private CISA” repository was maintained by an employee of Nightwing, a government contractor based in Dulles, Va. Nightwing declined to comment, directing inquiries to CISA.

CISA has not responded to questions about the potential duration of the data exposure, but Caturegli said the Private CISA repository was created on November 13, 2025. The contractor’s GitHub account was created back in September 2018.

The GitHub account that included the Private CISA repo was taken offline shortly after both KrebsOnSecurity and Seralys notified CISA about the exposure. But Caturegli said the exposed AWS keys inexplicably continued to remain valid for another 48 hours.

CISA is currently operating with only a fraction of its normal budget and staffing levels. The agency has lost nearly a third of its workforce since the beginning of the second Trump administration, which forced a series of early retirements, buyouts, and resignations across the agency’s various divisions.

The now-defunct Private CISA repo showed the contractor also used easily-guessed passwords for a number of internal resources; for example, many of the credentials used a password consisting of each platform’s name followed by the current year. Caturegli said such practices would constitute a serious security threat for any organization even if those credentials were never exposed externally, noting that threat actors often use key credentials exposed on the internal network to expand their reach after establishing initial access to a targeted system.

“What I suspect happened is [the CISA contractor] was using this GitHub to synchronize files between a work laptop and a home computer, because he has regularly committed to this repo since November 2025,” Caturegli said. “This would be an embarrassing leak for any company, but it’s even more so in this case because it’s CISA.”