The Everest ransomware group claimed a data breach targeting Petrobras, Brazil’s state-owned oil giant, alleging the theft of over 176 GB of seismic navigation data, with 90+ GB belonging directly to Petrobras. The compromised files include highly sensitive technical details—ship positioning, equipment configurations, hydrophone readings, depth measurements, quality control documents, metadata, and processed reports outlining survey progress and operational conclusions.Seismic surveys are critical for oil/gas exploration, requiring massive investments. Competitors gaining access to this data could replicate Petrobras’ methods, reduce their own costs, or leverage it in contract negotiations, undermining the company’s competitive edge. The group also targeted Campos Basin seismic surveys (3D/4D datasets), totaling another 90+ GB with similar sensitive information, including ship coordinates, source depths, and shot pressures.Everest demanded Petrobras contact them via Tox encrypted messaging within four days, threatening further action if ignored. The breach poses strategic risks to Petrobras’ industrial competitiveness and operational security, with potential long-term financial and reputational damage. The company has not yet publicly responded to the claims.