Eisai Co., Ltd.
atomsiloThis record tracks a ransomware attack claimed by the atomsilo group against Eisai Co., Ltd.. It collects the publicly disclosed attack details — sector, location and timeline — as published on the operator's leak site and indexed by Breach House.
Window Zero
EXPOSURE GAPWindow Zero is the time the breach stayed in the open before anyone said so — the gap between when the attack was first discovered on the operator's leak site (t1) and when it was publicly disclosed (t2). The wider this window, the longer victims, staff and customers were exposed with no warning.
Attack Summary
Eisai Co., Ltd. is a prominent Japanese pharmaceutical company headquartered in Tokyo that operates within the global healthcare services sector. The organization focuses on the research, development, and marketing of prescription medicines across various therapeutic areas, including neurology and oncology. As a research-driven entity, Eisai maintains a significant international presence to support its pharmaceutical product pipeline and patient care initiatives. This entity has been identified as a ransomware victim in a listing associated with the threat actor group known as AtomSilo.
Leak Screenshots
SAMPLEProof-of-breach screenshots the operator posted from the stolen data. Previews are redacted and locked — the originals are available on HaveIBeenRansom.