Amazon cloud servers - slush funds - malware uploads - unclassified servers.

CIA malware does not "explode on impact" but rather permanently infests its target. In order to infect target's device, copies of the malware must be placed on the target's devices, giving physical possession of the malware to the target. To exfiltrate data back to the CIA or to await further instructions the malware must communicate with CIA Command & Control (C2) systems placed on internet connected servers. But such servers are typically not approved to hold classified information, so CIA command and control systems are also made unclassified.

https://www.businessinsider.com/amazon-web-services-launches-secret-region-2017-11