Ethical Hacking News
Dentsu's U.S. subsidiary Merkle hit by cyberattack exposing sensitive staff and client data, forcing some systems offline to mitigate the security breach.
Dentsu's US-based subsidiary Merkle suffered a devastating cyberattack on October 30, 2025. The attack exposed sensitive staff and client data, including personal, payroll, and National Insurance details. Dentsu detected abnormal activity on part of Merkle's network and took swift action to mitigate the attack. The investigation found that hackers stole files containing information about current and former employees. The financial impact of the attack is unclear, but Dentsu is taking proactive steps to investigate and address the breach. The incident highlights the importance of robust cybersecurity measures for organizations worldwide.
Dentsu, a Japanese multinational advertising and public relations company, has recently suffered a devastating cyberattack on its U.S.-based subsidiary Merkle. The attack, which occurred on October 30, 2025, exposed sensitive staff and client data, including personal, payroll, and National Insurance details. This news comes as a significant blow to the company's reputation, particularly in light of the increasing threat of cyberattacks in recent years.
According to Dentsu's security incident notice, the company detected abnormal activity on part of Merkle's network, prompting an immediate response. The firm took certain systems offline to mitigate the attack and has since restored them, although it is currently unable to estimate the financial impact on the business. This swift action by Dentsu demonstrates its commitment to protecting sensitive data and minimizing potential damage.
The investigation into the cyberattack revealed that hackers stole files from Merkle's network, containing information concerning current and former employees. The affected individuals are being notified and offered free dark web monitoring as a precautionary measure. However, it remains unclear whether the company fell victim to a ransomware attack; at this time, no ransomware group has claimed responsibility for the attack on Merkle or Dentsu.
Merkle, Inc., a U.S.-based marketing and customer experience agency, operates as a subsidiary of Dentsu Group. With approximately 16,000 employees globally and estimated annual revenue of around US$1.5 billion, the company plays a crucial role in data-driven, performance-based marketing. The attack on Merkle highlights the growing importance of robust cybersecurity measures to protect sensitive information.
Dentsu has approximately 67,667 employees as of December 31, 2024, and its network systems in Japan were not impacted by the cyberattack. However, the company is taking proactive steps to investigate and address the breach, including collaborating with external cybersecurity firms and notifying relevant authorities in each impacted country.
The incident serves as a reminder of the ever-present threat of cyberattacks and the importance of robust security measures for organizations worldwide. As the use of technology continues to expand, the risk of data breaches increases, emphasizing the need for companies to prioritize cybersecurity and implement effective incident response plans.
The financial implications of this attack are still unclear, but it is evident that Dentsu's U.S.-based subsidiary Merkle has suffered a significant breach. The company's swift action in mitigating the attack demonstrates its commitment to protecting sensitive data and minimizing potential damage. However, the long-term effects of this incident will likely be felt for some time, underscoring the need for organizations to prioritize cybersecurity and develop robust incident response plans.
In light of this incident, it is essential for companies to review their security measures and take proactive steps to prevent similar breaches in the future. This includes implementing robust cybersecurity protocols, conducting regular security audits, and staying informed about emerging threats and vulnerabilities.
The Dentsu-Merkle cyberattack serves as a stark reminder of the importance of robust cybersecurity measures for organizations worldwide. As technology continues to evolve, the risk of data breaches increases, emphasizing the need for companies to prioritize cybersecurity and develop effective incident response plans.
Related Information:
https://www.ethicalhackingnews.com/articles/Dentsus-US-Subsidiary-Merkle-Hit-by-Sophisticated-Cyberattack-Exposing-Sensitive-Staff-and-Client-Data-ehn.shtml
https://securityaffairs.com/184017/data-breach/dentsus-us-subsidiary-merkle-hit-by-cyberattack-staff-and-client-data-exposed.html
https://cybersecuritynews.com/dentsu-merkle-suffers-cyberattack/
Published: Thu Oct 30 04:35:49 2025 by llama3.2 3B Q4_K_M
