Cyber Brief: Nikkei breach, Records leak, firefighter data exposed

Today’s Cyber Brief focuses on a trio of major data-exposure incidents: Japan’s Nikkei media group confirming a credentials-based compromise, a Swedish IT provider leaking 1.5 million records, and a U.S. municipal department mishandling personal data. Each case underlines how routine errors and endpoint hygiene failures can create large-scale risks that affect trust and compliance worldwide.

Nikkei discloses credentials-based breach affecting 17 000 users

Japanese media company Nikkei has confirmed that hackers accessed internal Slack accounts belonging to employees and partners after malware stole credentials from an infected personal computer. The attackers were able to view names, email addresses and chat logs from roughly 17 000 users. The company stated that journalistic sources and editorial data were not affected but acknowledged that lateral access inside corporate messaging systems had occurred. The breach investigation is ongoing.

Source: SecurityWeek

Why it matters:
Credential theft through personal or unmanaged devices remains one of the most common entry points for attackers. UK SMEs should ensure staff and contractors use corporate-managed endpoints, enable multifactor authentication on collaboration tools, and monitor access logs for unusual activity. Even trusted platforms like Slack or Teams can be exploited if device hygiene and credential discipline are weak.

Swedish IT firm Miljödata exposes 1.5 million personal records

Sweden-based software provider Miljödata AB is under investigation by the national data protection authority after an exposure affecting more than 1.5 million people. Early reports suggest misconfigured databases or public web interfaces allowed access to personal details tied to HR and payroll systems used by clients in healthcare and education. The company has not yet specified the affected data fields but confirmed that containment and notification measures are under way.

Source: CyberPress

Why it matters:
Large-scale data leaks caused by configuration errors remain a leading GDPR risk. For UK organisations handling EU-resident information or working with European suppliers, this highlights the need for continuous configuration audits, encryption of stored data, and rehearsed breach-notification processes. Prompt transparency and effective containment can significantly reduce regulatory and reputational damage.

Houston firefighter data incident exposes 7 500 social-security numbers

An administrative error within the Houston Fire Department led to a spreadsheet containing 7 500 firefighters’ names and social-security numbers being shared through an unsecured link. The file was circulated during promotion-exam preparations and discovered by staff after external access was detected. City officials have begun notifying affected personnel and reviewing data-handling policies.

Source: Click2Houston

Why it matters:
Accidental exposure of sensitive data remains a frequent cause of breaches in both public and private sectors. For UK SMEs, this reinforces the importance of applying access controls to every shared document, using password-protected links with expiry dates, and maintaining staff awareness about secure file-sharing. Human error is often the last barrier between compliance and compromise.

🔍 Today’s Key Actions

1. Review collaboration-tool access policies; require managed devices and MFA for all accounts.
2. Conduct a permissions and configuration audit across databases and file-storage systems.
3. Implement company-wide training on secure file-sharing and enforce password protection for all external links.

💬 Secarma Insight

Today’s incidents demonstrate that cyber resilience often depends less on sophisticated technology and more on disciplined everyday practice. Weak credentials, cloud misconfigurations and casual file-sharing still account for most data-exposure events. At Secarma, we help UK SMEs and regulated firms build sustainable resilience through policy enforcement, technical assurance and practical user awareness.

Get in touch with us to prioritise your next steps and strengthen your security posture.