Nikkei Suffers Breach Via Slack Compromise

Nikkei Inc. disclosed a data breach that exposed data and chat histories for more than 17,000 Slack accounts, with 17,368 individuals potentially affected. The breach stemmed from an unauthorized external login in the Slack workspace after a personal computer used by an employee was infected with a virus, leading to leakage of Slack authentication credentials.

According to Nikkei Inc., these credentials were used to gain unauthorized access to employee accounts, and the incident was identified in September, with countermeasures such as password changes implemented. The compromised data included names, email addresses, and chat histories for the affected users, covering both employees and business partners, though the extent to third parties remains unclear. The incident underscores how corporate communications platforms can present rich attack surfaces for threat actors.

Nikkei said it voluntarily reported the matter to the Personal Information Protection Commission to ensure transparency.