Sandworm-Associated DynoWiper Malware Targets Polish Power Infrastructure
A cyber intrusion targeting the nation's energy infrastructure occurred in late 2025, which security experts have described as one of the largest cyberattacks the nation has faced in many years. It underscores the growing vulnerability of critical national systems in light of increasing geopolitical tensions, which are at odds with one another.
ESET, a cybersecurity company specializing in cyber security, has uncovered new data indicating that the operation was carried out by Sandworm, an advanced persistent threat group closely aligned with Russia that has been associated with disrupting energy and industrial networks for decades.
ESET researchers found that a deeper analysis of the malware used during the incident revealed operational patterns and code similarities that are consistent with Sandworm's past campaigns, indicating that the attack follows Sandworm's established playbook for damaging cyber activity.
According to the assailants, they were planning to use a malware strain named DynoWiper that was designed to permanently destroy files and cripple affected systems by irreversibly destroying them, a strategy which could have caused widespread disruptions across the Poland electricity industry if it had been successful.
At the time of publication, the Russian Embassy in Washington did not respond to requests for comment.
According to cyber experts, Sandworm, which is also known as UAC-0113, APT44, or Seashell Blizzard in the cybersecurity community, has been active for more than a decade and is widely regarded as an act of state-sponsored hacking, most likely aimed at Russian military intelligence agencies.
The group's ties to Unit 74455 of the Main Intelligence Directorate (GRU) have been established by security researchers after repeated accusations that the organization has committed high-impact cyber-operations intended to disrupt and degrade critical infrastructure systems.
Throughout its history, Sandworm has been credited with some of the most significant cyber incidents against energy networks, most notably a devastating attack on the Ukraine's power grid nearly a decade ago, which used data-wiping malware and left around 230,000 people without power for a period of nearly 10 days.
It is important to note that this episode still remains a prototypical example of the group's capabilities and intentions, and it continues to shape the assessment of the group's role in more recent attempts to undermine energy systems beyond Ukraine's borders.
As detailed in a recent report issued by ESET, they believed that the operation bore the hallmarks of Sandworm, a threat actor widely linked to Russia's military and intelligence apparatus, evidenced by its involvement in the operation.
A data wiping malware, DynoWiper, dubbed DynoWiper, was identified by investigators and tracked as Win32/KillFiles.NMO, which had previously been undocumented, pointing the finger at the group. The wiper campaign was similar in both technical and operational aspects to earlier Sandworm wiper campaigns, especially those that were observed following Russian invasion of Ukraine in February of that year.
In a statement published by ESET on December 29, 2025, the company stated that the malware had been detected during an attempt to disrupt Poland's energy sector, but that there are no indications that the attackers succeeded in causing outages or permanently damage the energy sector.
In an email sent on December 29, the Polish authorities confirmed that there was activity observed in the area of two combined heat and power plants and a system used to manage the generation of electricity from renewable sources, such as the power of wind and sun.
In a public statement, the Prime Minister said that the attacks were directed by groups “directly linked to Russian services,” citing the government's plans to strengthen national defenses through additional safeguards and cybersecurity legislation that will require more stringent requirements on risk management, information technology and operational technology security, and preparedness for incidents. Tusk said this legislation is expected to be implemented very soon.
Moreover, the timing of the incident attracted the attention of analysts as it coincided with the tenth anniversary of Sandworm's historic attack on Ukraine's power grid in 2015. BlackEnergy and KillDisk malware were deployed during the attack, and the attack caused hours-long blackouts for thousands of people, something that was cited as a continuation of a pattern of disruption campaigns against critical infrastructure that has been occurring for years.
A company named ESET stated that the attempted intrusion coincided with Sandworm's tenth anniversary of the devastating attack on Ukraine's power grid in the year 2000, though it only provided limited technical information beyond the identification of the malware involved.
Researchers are pointing out that the use of a custom-built wiper, as well as the pattern of Russian cyber operations in which data-destroying malware has been a strategic tool, aligns with a broader pattern observed in cyber operations.
The use of wipers in attacks linked to Moscow has increased significantly since 2022.
The use of AcidRain to disable roughly 270,000 satellite modems in Ukraine has been an effort to disrupt the communication of the country. A number of campaigns targeting universities, critical infrastructure, and the like have been attributed to Sandworm.
This is also true in the case of the NotPetya outbreak in 2017, a destructive worm that in its early stage was targeted at Ukrainian targets, but quickly spread worldwide, causing an estimated $10 billion in damage and securing its place as one of the highest-profile case studies in the history of cybercrime.
There are no indications yet as to why DynoWiper had failed to trigger power outages in Poland; the investigation has left open the possibility that the operation may have been strategically calibrated to avoid escalation or that strong defenses within the country’s energy grid prevented it.
In the aftermath of the incident, governments and operators of critical infrastructure across Europe have been reminded once again that energy systems continue to be an attractive target among state-sanctioned cyber operations even when those attacks do not result in immediate disruptions.
It is noted that security analysts have noted the attempt to deploy DynoWiper in a strategic capacity reflects a continued reliance on destructive malware as a strategy tool, and emphasize the importance of investing in cyber resilience, real-time monitoring, and coordinated incident response across both the information technology as well as operational technologies.
Although it appears that Polish officials are using the episode as a springboard in order to strengthen their defenses, experts point out that similar threats may not be bound by borders in the near future since geopolitical tensions are unlikely to ease at all.
Despite the fact that the failure of the attack may offer some reassurance for the time being, it also emphasizes a more significant reality: adversaries continue to search energy networks for weaknesses, and it will be crucial to be prepared and cooperative if we wish to avoid future disruptions, as well as to be able to detect and neutralize malware before it becomes a major problem.
