Wisconsin-based wireless provider Cellcom has confirmed that a cyberattack caused the service outage impacting thousands of customers across Wisconsin and Upper Michigan. For over a week, customers experienced disruptions to voice and text services. While some services are now gradually coming back online, full restoration is still in progress.
Cellcom CEO Brighid Riordan addressed the issue directly in a letter to customers, stating, “We experienced a cyber incident. While unfortunate, it’s not something we were unprepared for. We have protocols and plans in place for exactly this kind of situation.”
The company notified federal authorities and is working closely with external cybersecurity experts to investigate the incident and ensure a secure recovery process.
No Customer Data Compromised, But Recovery Continues
Cellcom reassured users that no personal data was accessed in the breach. The attack targeted a network segment that does not store sensitive customer information, including names, addresses, or financial records.
“We have no evidence that personal information related to you […] is impacted by this event,” the company emphasized.
While progress is being made, the timeline for full service restoration remains uncertain. Cellcom acknowledged a key milestone was reached overnight and noted that recovery work continues with caution and precision. “We expect to have the rest of service restored this week,” the carrier added. “Every part of this recovery is being handled with care — we will not rush anything that compromises safety, security, or trust.”
So far, Cellcom has not revealed the nature of the cyberattack. Although the scope of the outage suggests a possible ransomware attack, no known ransomware groups have claimed responsibility as of yet.
Efforts to contact Cellcom for further comment were unsuccessful. The company’s public relations inbox currently blocks messages from outside senders, including press inquiries.
