Ransomware known as Seftad overwrites the master boot record on infected machines and demands a payment of $100 to reverse the damage. After infection, it tells victims that their hard drives have been encrypted and that any attempt to recover their files will result in data loss. The malware simply replaces the infected PC s MBR with a malicious one. Using the password aaaaaaciip without the quotation marks will deactivate the malware and restore the original MBR.
Source: https://threatpost.com/new-seftad-ransomware-attacks-master-boot-record-113010/74714/