Malware
DoppelPaymer
aka Pay OR Grief
Doppelpaymer is a ransomware family that encrypts user data and later on it asks for a ransom in order to restore original files.
DoppelPaymer, also known as Pay OR Grief, is a Windows malware family operated by DOPPEL SPIDER.
Background
Doppelpaymer is a ransomware family that encrypts a victim's data and then demands a ransom for the recovery of the original files. It can be identified by the signature .doppeled extension it appends to encrypted files, and it drops a ransom note named ".how2decrypt.txt".
Source: Malpedia (Fraunhofer FKIE).