The access enabled Clop ransomware actors to deploy a malicious web shell and steal troves of sensitive data from a number of clients. The group began to directly extort Accellion clients in January, threatening to leak the exfiltrated information. The ongoing tally includes at least 100 impacted companies, affecting more than 3.51 million patients. For Cayuga Medical, the impacted data was tied to its vendor, Guidehouse, which was compromised by the Accellion incident. The data could include patient names, dates of birth, some medical information, and insurance account numbers. Affected patients will receive free credit monitoring services. The ongoing investigation shows only a fraction of Cayuga Medical's patients were impacted. The incident is not yet listed on the Department of Health and Human Services' breach reporting tool, so the exact total is unknown for now.