The cybersecurity authorities of Australia, New Zealand, Singapore, the United Kingdom, and the United States have released Joint Cybersecurity Advisory AA21-055A: Exploitation of Accellion File Transfer Appliance. Cyber actors worldwide have exploited vulnerabilities in Accellion File Transfer Appliance to attack multiple federal, and state, local, tribal, and territorial government organizations as well as private industry organizations in the medical, legal, telecommunications, finance, and energy fields. In some instances, the attacker extorted money from victim organizations to prevent public release of information exfiltrated from a compromised Accellion appliance.
CISA encourages users and administrators to review AA21-055A: Exploitation of Accellion File Transfer Appliance and MAR-10325064-1.v1 – Accellion FTA for more information.