An example method of secure attestation of a workload deployed in a virtualized computing system is described. The virtualized computing system includes a host cluster and a virtualization management server, the host cluster having hosts and a virtualization layer executing on hardware platforms of the hosts. The method includes: launching, in cooperation with a security module of a host, a guest as a virtual machine (VM) managed by the virtualization layer, the security module generating an attestation report from at least a portion of the VM loaded into memory of the host; sending the attestation report from the security module to a trust authority; receiving, in response to verification of the attestation report by the trust authority, a secret from the trust authority at the security module; and providing the secret from the security module to the guest.