data exfiltration is the unauthorized transfer of data from an organization's network to an external destination, usually for malicious purposes such as espionage, sabotage, or theft. The details given in the question suggest that data exfiltration is occurring from an endpoint device. The bursts of network utilization every seven days indicate periodic data transfers. The content being transferred appears to be encrypted or obfuscated to avoid detection or analysis. The persistent outbound TCP connection from the host to infrastructure in a third-party cloud indicates a possible command and control channel for an attacker. The HDD utilization on the device grows by 10GB to 12GB over the course of every seven days, and single file sizes are 10GB, indicating that large amounts of data are being collected and compressed before being exfiltrated.

The first action that should be taken to prevent a more serious compromise is to check the hash signatures, comparing them with malware databases to verify if the files are infected. This will help to determine if the changes to hash signatures were caused by malicious software or legitimate updates. If the files are infected, they should be quarantined and removed from the network. Checking the hash signatures will also help to identify the type and source of the malware, which can inform further actions such as blocking malicious domains or IPs, updating antivirus signatures, or notifying users3.