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Cellcom, a Wisconsin-based mobile carrier, has confirmed that a cyberattack is the cause of a week-long service outage that began on the evening of May 14, 2025. Customers across Wisconsin and Upper Michigan experienced disruptions to voice and SMS services, leaving them unable to make phone calls or send text messages. Initially, the company attributed the issue to a technical problem but later acknowledged the cyber incident in a video and letter from CEO Brighid Riordan. The attack specifically targeted a network segment responsible for handling voice and SMS, but the company assured customers that sensitive data, such as names, addresses, and financial details, was not compromised.

Cellcom has engaged federal authorities, including the FBI, and international cybersecurity experts to assist in mitigating the impact and restoring full service. CEO Brighid Riordan stated that the company was not unprepared for such an incident and emphasized their commitment to recovery. Partial service has been restored, and the company anticipates a full restoration by the end of the week. Cellcom has also pledged to cover service fees for affected customers during the outage as a gesture of accountability and thanks.

The cyberattack on Cellcom highlights the critical importance of cybersecurity and the potential consequences of a breach on essential communication services. The outage has disrupted both personal and business communications, with some customers reporting business losses due to the prolonged downtime. The Wisconsin Department of Agriculture, Trade and Consumer Protection has received at least 15 customer complaints related to the disruption. Cellcom is advising affected users to try turning on their phone’s airplane mode for 10 seconds or restarting their device if they continue to experience connection issues.

ImgSrc: dysruptionhub.c

References :

• bsky.app: Wisconsin wireless provider Cellcom has confirmed that a cyberattack is responsible for the widespread service outage and disruptions that began on the evening of May 14, 2025.
• The Dysruption Hub: Cyberattack Disrupts Cellcom Voice and Text Services in Wisconsin
• The DefendOps Diaries: The Cellcom Cyberattack: Lessons in Cybersecurity and Communication Resilience
• PCMag UK security: Cyberattack Takes Down Wisconsin-Based Mobile Carrier
• www.bleepingcomputer.com: Mobile carrier Cellcom confirms cyberattack behind extended outages
• BleepingComputer: Infosec Exchange post confirming Cellcom cyberattack
• securityaffairs.com: A cyberattack was responsible for the week-long outage affecting Cellcom wireless network

Classification:

• HashTags: #cyberattack #Cellcom #serviceoutage
• Company: Cellcom
• Target: Cellcom
• Product: Mobile communication services
• Feature: Phone and text services
• Malware: Unspecified
• Type: Hack
• Severity: Medium