In August 2017, the Commission learned that an incident previously detected in 2016 may have provided the basis for illicit gain through trading. Specifically, a software vulnerability in the test filing component of the Commission’s EDGAR system, which was patched promptly after discovery, was exploited and resulted in access to nonpublic information. It is believed the intrusion did not result in unauthorized access to personally identifiable information, jeopardize the operations of the Commission, or result in systemic risk. An internal investigation was commenced immediately at the direction of the Chairman.

Source: SEC.gov | SEC Chairman Clayton Issues Statement on Cybersecurity