A cybersecurity incident at Eurofiber France was officially confirmed after the company identified unauthorized activity on November 13, 2025. The incident involved a software vulnerability that allowed a malicious actor to access data from Eurofiber France’s ticket management platform and the ATE customer portal.
According to the company, the situation is now under control, with systems secured and additional protective measures implemented.
Cybersecurity Incident Impacted Ticketing Platform and ATE Portal
Eurofiber France stated that the cybersecurity incident affected its central ticket management platform used by regional brands Eurafibre, FullSave, Netiwan, and Avelia. It also impacted the ATE portal, part of Eurofiber France’s cloud services operating under the Eurofiber Cloud Infra France brand. The company confirmed that the attacker exploited a software vulnerability in this shared environment, leading to the exfiltration of customer-related data.
The company emphasized that the incident is limited to customers in France using the affected platforms. Customers using Eurofiber services in Belgium, Germany, or the Netherlands, including Eurofiber Cloud Infra in the Netherlands, were not impacted.
Eurofiber also noted that the effect on indirect sales and wholesale partners within France remains minimal, as most partners operate on separate systems.
Immediate Response and Containment Measures
Within hours of detecting the breach, Eurofiber France placed both the ticketing platform and the ATE portal under reinforced security. The vulnerability was patched, and additional layers of protection were deployed. The company said its internal teams, working alongside external cybersecurity experts, are now focused on assisting customers in assessing and managing the impact.
Eurofiber clarified that no sensitive financial information, such as bank details or regulated critical data stored in other systems, was compromised. All services remained fully operational during the attack, and there was no disruption to customer connectivity or service availability.
Customers were notified immediately after the breach was detected. Eurofiber stated it would continue to update affected organizations transparently as the investigation progresses.
Regulatory Notifications and Ongoing Investigation
In line with European regulatory requirements, Eurofiber France has notified the CNIL (France’s Data Protection Authority under GDPR) and reported the incident to ANSSI (the French National Cybersecurity Agency). A police complaint has also been filed in connection with an extortion attempt linked to the attack.
The company reaffirmed its commitment to transparency, data protection, and cybersecurity throughout the remediation process.
External Research Points to Larger Data Exposure
International Cyber Digest, a third-party cybersecurity research group, reported that the breach may have exposed information belonging to approximately 3,600 customers. According to their analysis, the threat actor — who identifies as “ByteToBreach” — gained full access to Eurofiber’s GLPI database, including client data, support tickets, internal messages, passwords, and API keys.
Researchers noted that Eurofiber’s GLPI installation may have been operating on versions 10.0.7–10.0.14, potentially outdated and vulnerable. The attacker, in comments shared with the researchers, claimed to have executed a slow, time-based SQL injection attack and extracted nearly 10,000 password hashes over a period of 10 days. They reportedly used administrator-level API keys to download internal documents and customer PII.
ByteToBreach also claimed to have contacted both GLPI’s developer, Teclib, and Eurofiber to negotiate ransom demands. According to the research group, those attempts received no response.
Eurofiber France operates over 76,000 kilometers of fiber network and 11 data centers, serving between 9,000 and 12,000 business and government customers. The company’s French clientele includes several major public institutions and private-sector organizations.
Eurofiber France reiterated that all systems have now been secured and that enhanced monitoring and preventive measures are in place. The company said its teams remain fully mobilized until the cybersecurity incident is completely resolved.