Spanish telecommunications giant Telefonica recently fell victim to a significant cybersecurity breach, showing that even large organizations can be vulnerable. The event highlights how important it is to maintain strong defenses, especially against infostealers, which are designed specifically to steal information.
The Breach: What Happened?
This month (January 2025), Telefonica confirmed unauthorized access to its internal Jira ticketing system. The breach, orchestrated by a group of attackers allegedly linked to the Hellcat ransomware group, resulted in the theft of approximately 2.3 GB of sensitive data. The stolen information included:
- 24,000 employee emails and names
- 500,000 Jira issues and summaries
- 5,000 internal documents
- 236,493 lines of customer data
The Attack Vector: Infostealer Malware
The breach was facilitated by infostealer malware, a type of malicious software designed to harvest sensitive information such as login credentials from infected devices. Numerous employees were reported to be compromised, providing attackers with critical credentials for initial access.
The Broader Infostealer Problem at Telefonica
Data from Twilight Cyber reveals the alarming extent of compromises Telefonica experienced in 2024 alone:
- 469 employee credentials on Telefonica’s domain were compromised.
- 266 customer credentials on Telefonica’s domain were exposed.
- 3,163 employee credentials on third-party services (e.g., Office365, Salesforce) were stolen. This includes JIRA which was the main facilitator of this breach.

Over 100 employee machines were confirmed to be infected with infostealers.
These infections allowed attackers to harvest corporate credentials across multiple platforms, including Active Directory access to cloud services, intranet logins, webmail accounts, and third-party systems.
The Role of Social Engineering
Once inside Telefonica’s systems, the attackers employed sophisticated social engineering techniques to expand their access. They targeted two employees with administrative privileges, tricking them into revealing critical information that enabled brute-forcing SSH access.
Infostealer attacks like these are completely preventable: The Twilight Cyber Solution
This breach highlights the urgent need for proactive infostealer threat intelligence. Platforms like Twilight Cyber provide real-time detection of compromised credentials and infected machines, offering organizations a chance receive alerts to breached machines and compromised credentials, enablind them to mitigate threats before they escalate. Twilight Cyber’s solution delivers:
- Real-time dark web monitoring for compromised credentials and machines
- Rapid detection of machine infections within hours
- Instant verification of credential security during user logins with Account Takeover Prevention
- Hourly updates on compromised machines and credential information
Companies like Telefonica could significantly enhance their cybersecurity posture by leveraging Twilight Cyber’s advanced threat intelligence platform. This solution would enable them to:
- Proactively identify infected machines using unique identifiers, allowing for swift remediation before attackers can exploit vulnerabilities.
- Efficiently remove malware with precise path information, minimizing downtime and reducing the risk of data exfiltration.
- Instantly update compromised credentials, creating a robust defense against unauthorized access attempts.
Moreover, Twilight Cyber’s platform offers seamless integration with Identity and Access Management (IAM) systems, enabling automatic account takeover prevention measures. This integration empowers organizations to:
- Implement real-time credential monitoring and validation during login attempts.
- Automatically trigger additional authentication factors for potentially compromised accounts.
- Instantly revoke or suspend access for confirmed compromised credentials.
By adopting such a comprehensive and automated approach, companies like Telefonica can stay one step ahead of cyber threats, significantly reducing the risk of successful breaches and maintaining the integrity of their digital infrastructure.

Moving Forward
The Telefonica breach serves as a cautionary tale for organizations worldwide. It highlights the need for:
- Proactive infostealer threat intelligence solutions like Twilight Cyber.
- Regular security audits and employee training on phishing and social engineering.
- Strong password policies combined with multi-factor authentication.
- Rapid incident response capabilities to contain breaches quickly.
As cyber threats continue improve, organizations must adopt comprehensive security measures to stay ahead of attackers.
Contact us to schedule a demo and see how Twilight Cyber can help keep your data off the dark web.