Below are two signatures for the ciurrent version of Magniber ransomware, which is targeting Asia, especially South Korea, via exploit kits. Copy them, put them n a Notepad file, and save it to the ClamWin db folder with the filename of Sigfile.mdb. Do not save it as a text file--make sure it is named Sigfile.mdb in the db folder (without a .txt on the end). The signature will probably last for several weeks, after which you can delete it because the malware authors will probably have a newer version after that. I keep my custom signatures like this for about a month and then delete them.

32256:6f945ab875fa638173fa42224a382859:Win.Trojan.Ransom-071618.1340
35840:a9d27275d880e0ba0cda3c1a9d1ba0f7:Win.Trojan.Ransom-071618.1338

Regards,