What happens after a ransom is paid to a fraudster in a ransomware attack?

After a ransom is paid to a fraudster in a ransomware attack, there is no guarantee that victims will receive a valid decryption key to unlock their files. This highlights the inherent risks involved in paying ransomware, as fraudsters may choose to either provide a key that does not work or not provide one at all. Even if the payment is made, there is the possibility that the attackers could have already exfiltrated sensitive data and could ask for further payments to not release that information publicly, or they might simply choose to disappear without fulfilling their end of the deal.

In the context of the other options, while some victims might experience recovery after payment, this is not universally applicable. Access to locked files is not guaranteed (contrary to the first option). The malware's removal is also not a certain outcome, as paying does not involve any automated process for cleaning the infected machine (which addresses the second option). Additionally, it is possible that fraudsters might take advantage of the situation by demanding more payments or escalating their tactics, which relates to the last option regarding upgrading the ransomware. However, the most critical and relevant aspect remains that victims may not receive the promised decryption key after payment.