Cellcom aWisconsin-based wireless provider, has officially confirmed that a cyberattack is behind a major outage of its network that began on the evening of May 14, 2025. The incident affected thousands of subscribers, disrupting critical phone and SMS services in areas of Wisconsin and Upper Michigan.
After several days of silence and initial statements of a “technical problem,” Cellcom CEO Brighid Riordanhas officially admitted to a cyberattack. In a letter , she notes that the company had already anticipated such incidents and immediately activated crisis response protocols.
The company says it immediately worked with cybersecurity experts and notified the appropriate authorities, including the FBI, and immediately began restoring systems.
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According to Riordan, the attack was limited to network infrastructure that does not host users' personal or financial data, and – so far – there is no indication of a breach of sensitive information.
Initially, Cellcom announced that the outages were only related to technical issues and that essential services, such as mobile data, iMessage, RCS and emergency calls , remained active. However, the delayed admission of the truth, combined with the difficulty of customers to port their numbers to other providers due to Cellcom's problems, caused strong dissatisfaction.
According to an announcement by the company on May 19, basic functions such as sending/receiving SMS and voice calls between Cellcom subscribers were selectively restored.
Despite the first signs of progress, the company is avoiding giving a specific timeline for the full restoration of services. As stated in a relevant update on the Cellcom website, the goal remains full functionality by or before the end of the week, but without guarantees.
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For subscribers who are still experiencing connection problems, Cellcom suggests temporarily activating flight mode for 10 seconds or, alternatively, restarting the device.
Despite growing concerns, the company is still not answering questions about whether the attack is related to ransomware or other forms of targeted cybercrime.
However, Cellcom CEO Brighid Riordan released a video message to customers, explaining the situation and the actions being taken to restore services, attempting to enhance transparency and trust amid the crisis.
The cyberattack on Cellcom is indicative of the systemic risks that telecommunications providers, regardless of size or location. Although not one of the industry’s “giants,” Cellcom serves critical areas and the disruption of essential services – such as voice calls and SMS – immediately jeopardized daily communication and access to emergency services.
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What's worrying is not only the technical scope of the attack, but also the fact that it took days for the company to admit the true nature of the problem. This is hurting subscriber confidence.
In an era where cybersecurity must be treated as a public infrastructure, such attacks highlight the need for stronger protocols, transparency, and faster response.
Source: www.bleepingcomputer.com
