Incorrect Access Controls of Security Officer (SO) in PKCS11 R2 provider that ships with the Utimaco CryptoServer HSM product package allows an SO authenticated to a slot to retrieve attributes of keys marked as private keys in external key storage, and also delete keys marked as private keys in external key storage. This compromises the availability of all keys configured with external key storage and may result in an economic attack in which the attacker denies legitimate users access to keys while maintaining possession of an encrypted copy (blob) of the external key store for ransom. This attack has been dubbed reverse ransomware attack and may be executed via a physical connection to the CryptoServer or remote connection if SSH or remote access to LAN CryptoServer has been compromised. The Confidentiality and Integrity of the affected keys, however, remain untarnished.