The firm added that it does not appear core IT systems have been compromised, as the route of access was isolated from the rest of Shell's central infrastructure. However, the data breach has been connected to Accellion's File Transfer Appliance (FTA), enterprise software used to transfer large files — and a solution linked to a string of security incidents in December 2020 and January 2021. Accellion FTA, a legacy product that has now been formally retired, contained a zero-day vulnerability that was patched within three days of the vendor being made aware of active attacks utilizing the security flaw. However, thousands of organizations worldwide rely on the appliance, leading to a string of attacks against high-profile corporations and government entities. The first case was reported by the Reserve Bank of New Zealand. Organizations including the Australian Securities and Investments Commission (ASIC), Singtel, and Qualys soon followed.