Paris-area wastewater agency SIAAP hit by cyberattack

Service public de l'assainissement francilien (SIAAP), the public body that treats wastewater for the Paris region, was hit by a cyberattack that began on Friday, November 17, 2023. The agency announced the incident publicly in the days that followed and described the operation as highly structured.

SIAAP serves roughly nine million people across four departments in the Ile-de-France region and operates close to 275 miles of piping. The agency said the intrusion affected its administrative information technology, including email, human resources and general administration systems. It stated that industrial control systems were not affected and that wastewater transport and treatment continued without interruption.

Responders convened a crisis unit and cut external connection paths into the network to stop the attack spreading. SIAAP filed a complaint with judicial police and notified CNIL, the French data protection authority. The Record reported that an emergency order was issued allowing the agency to hire outside cybersecurity firms and buy whatever equipment was needed to recover systems.

No group claimed responsibility, and neither a ransom demand nor data encryption was confirmed publicly, though The Record noted that water authorities have been a prime target for ransomware gangs. SIAAP said staff were working under badly degraded conditions and that a full return to normal would take several weeks. The investigation remained open at the end of November 2023.