Ransomware: thegentlemen claims Holborn European Marketing (CY) — Professional Services

On 7 August 2026, the ransomware group "thegentlemen" added Holborn European Marketing (CY) to its leak site under the BREACH framework, claiming a successful intrusion. The publication on ransomware.live indicates that the group has exfiltrated data and is likely threatening to release it unless a ransom is paid. No technical details, such as the attack vector or volume of data, were disclosed in the initial listing.

This incident affects Holborn European Marketing, a Cyprus-based entity operating in the professional services sector. Given the group’s pattern, the breach may also have downstream implications for the firm’s clients, particularly those in financial services or cross-border marketing, who could face secondary data exposure. The professional services sector is a high-value target due to its access to sensitive client and financial information.

Compliance teams should immediately verify whether their organisation has any data-sharing relationship with Holborn European Marketing and assess potential third-party risk. Review your incident response plan to ensure it covers supply-chain ransomware scenarios, and confirm that contractual breach notification clauses are activated if your data is involved. Additionally, monitor the leak site for any published samples, and coordinate with legal counsel on regulatory reporting obligations under GDPR, as any EU personal data exfiltration would trigger a 72-hour notification to the supervisory authority. Finally, reinforce employee awareness around phishing and remote access vulnerabilities, as these remain the most common entry points for such groups.