Intrusion setG0033

Poseidon Group

Poseidon Group is a Portuguese-speaking threat group that has been active since at least 2005. The group has a history of using information exfiltrated from victims to blackmail victim companies into contracting the Poseidon Group as a security firm.

Documented techniques
8
Assessed motivation
Data theft
First seen
2005
Basis
MITRE ATT&CK

How they break in

Techniques MITRE has documented this group using, grouped by the stage of an attack they belong to. This is the actionable half: each one is a behaviour you can look for in your own logs, and a control you can test.

Source: MITRE ATT&CK View the original record · Last synchronised 2026-09-09 · Origin and motivation are read from MITRE’s own description and are not structured fields in ATT&CK. Where the text does not attribute a group, this page leaves them blank rather than guessing.