Polish officials reported a failed late-December cyberattack targeting the country’s energy infrastructure, described by Energy Minister Milosz Motyka as the “strongest attack” on the sector in years. The activity on December 29–30 targeted two combined heat and power (CHP) plants and attempted to disrupt systems and communications supporting electricity management from renewable sources (including wind and photovoltaic installations) and their links to power distribution operators; local reporting indicated the impact could have been significant if successful.
Security firm ESET said the attempted disruptive operation involved a previously undocumented wiper malware it named DynoWiper, designed to irreversibly destroy data and render systems inoperable. ESET attributed the activity with medium confidence to Sandworm (a GRU-linked threat actor) based on overlaps with prior Sandworm-associated destructive campaigns, particularly against Ukraine’s energy sector; Polish leadership publicly blamed Russia-linked groups and indicated additional safeguards and cybersecurity legislation were being prepared to strengthen IT/OT risk management and incident response. Both reporting noted the timing was close to the 10-year anniversary of Sandworm’s 2015 attacks on Ukraine’s power grid.

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On February 5, 2026, Elastic Security Labs released a technical analysis of a DynoWiper sample, describing its file-corruption behavior, exclusions, and reboot logic. Elastic also published hashes, IP indicators, a YARA rule, and noted that canary-based EDR protections had stopped overwriting on more than 100 machines at the CHP plant.
The CERT report said the attacks disrupted communications and remote control at renewable sites but did not stop electricity generation, while the attempt to affect heat supply at the CHP plant failed. In the CHP environment, an EDR product reportedly blocked DynoWiper execution, preventing broader destruction.
CERT Polska said the attackers primarily gained access through internet-exposed Fortinet FortiGate VPN and firewall devices, often unpatched and lacking multi-factor authentication, then reused credentials and moved laterally through Active Directory. The report also described months of reconnaissance, credential theft, and attempts to access Microsoft 365 from on-premises credentials.
On January 30–31, 2026, CERT Polska released a technical report detailing coordinated attacks on 30-plus wind and solar farms, a manufacturing company, and a major CHP plant. CERT attributed the activity to Static Tundra, also tracked as Berserk Bear/Ghost Blizzard/Dragonfly and linked to Russia's FSB Center 16, creating a public attribution dispute with ESET and Dragos.
Dragos assessed with medium confidence that the operation was conducted by ELECTRUM, a cluster it says overlaps with the Sandworm/APT44 ecosystem, with KAMACITE possibly supporting access operations. The firm said the attackers likely exploited exposed network devices and vulnerabilities in RTUs and communications infrastructure.
On January 28, 2026, Dragos reported that the campaign compromised control and communications systems at roughly 30 distributed energy facilities and gained access to OT systems. Dragos said some key equipment was disabled beyond repair and characterized the operation as a first major cyberattack focused on distributed energy resources.
By January 23–24, 2026, ESET publicly analyzed the malware used in the incident, named it DynoWiper (Win32/KillFiles.NMO), and attributed the operation to the Russia-aligned Sandworm group with medium confidence. ESET said it was not aware of any successful disruption and cited overlap with Sandworm's prior destructive tooling and tactics.
In the aftermath of the attack, Polish officials described it as the strongest or one of the largest attacks on the country's energy infrastructure in years, and Prime Minister Donald Tusk said indications pointed to groups linked to Russian services. The government also said it was preparing stronger safeguards and cybersecurity legislation covering IT/OT risk management and incident response.
Polish authorities and responders detected and mitigated the attack before it could interrupt national electricity or heat supply. Reporting indicates communications and control were impaired at affected sites, but critical infrastructure remained operational and no grid-wide outage occurred.
During the late-December operation, the intruders used the previously undocumented DynoWiper wiper and, in some reporting, a PowerShell-based wiper called LazyWiper, alongside firmware tampering, controller resets, and other destructive actions. These actions disrupted monitoring and remote-control capabilities and in some cases damaged equipment beyond repair, but did not cause a blackout.
On December 29–30, 2025, attackers targeted more than 30 wind and solar facilities, two heat-and-power/combined heat and power plants, and related communications and control systems in Poland. The operation aimed to disrupt communications between distributed renewable installations and power distribution operators during peak winter conditions.
CERT Polska later reported that in the combined heat and power plant case, the intruders had been stealing data and escalating access since March 2025, focusing on OT modernization and SCADA-related information. This established that the December sabotage attempt was preceded by months of reconnaissance and preparation.
In December 2015, Sandworm conducted a cyberattack on Ukraine's power grid that caused significant outages, a benchmark repeatedly cited by later reporting on the Poland incident. The event is referenced as the first known malware-induced blackout and as a precursor to later grid-focused operations.
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