Japanese media conglomerate Nikkei disclosed a significant cyberattack after unauthorized actors infiltrated its internal Slack workspace using stolen credentials. The breach compromised personal information, email addresses, and chat histories belonging to more than 17,000 employees and business partners. Company investigators determined that the intrusion stemmed from an infostealer malware infection that captured valid user session details. Despite the widespread access to workspace chats, Nikkei confirmed that it has found no evidence that sensitive journalistic sources or proprietary reporting data were leaked. In response to the security incident, the media group immediately revoked compromised credentials, forced widespread password resets, and launched a comprehensive internal review.

Full report : Attackers breach internal chat environment, exposing data of over 17,000 individuals.