This week we have seen three new Dharma Ransomware variants released that append either the .Gamma, .Bkp, & .Monro extensions to encrypted files.
It is highly unusual for this ransomware family to release so many variants released in a short period of time. Typically, one variant used for a month, if not more, and then a new variant is released. Instead, we saw three new variants released in the same week.
All three variants were discovered by security researcher Jakub Kroustek, who posted the samples on Twitter.
Less than a week, and there's yet another version of the #CrySiS #ransomware - extension ".gamma" (".id-%ID%.[firstname.lastname@example.org].gamma") + ransomnotes in "FILES ENCRYPTED.txt". https://t.co/4eKDceeTAg pic.twitter.com/LPoQxpxIqX— Jakub Kroustek (@JakubKroustek) September 16, 2018
Another day, another new #CrySiS/#Dharma #ransomware varianta - this time with ".monro" extension and usual "FILES ENCRYPTED.txt" & "Info.hta" ransom notes. Email "email@example.com" (@gexcolo). https://t.co/sUMmNP6KOQ + https://t.co/FXYEndpVKh pic.twitter.com/VuBGB0bfEJ— Jakub Kroustek (@JakubKroustek) September 18, 2018
When victims are infected with these variants their files will be encrypted and renamed. Depending on the particular variant they are infected with a file called test.jpg would be encrypted and renamed to test.jpg.id-%ID%.[firstname.lastname@example.org].gamma, test.jpg.id-%ID%.[email@example.com].monro, or test.jpg.id-%ID%.[firstname.lastname@example.org].bkp.
These ransomware infections will also drop a ransom note named FILES ENCRYPTED.txt that contains payment instructions.
In order to protect yourself from Dharma, or from any ransomware, it is important that you use good computing habits and security software. First and foremost, you should always have a reliable and tested backup of your data that can be restored in the case of an emergency, such as a ransomware attack.
As the Dharma Ransomware is typically installed via hacked Remote Desktop services, it is very important to make sure its locked down correctly. This includes making sure that no computers running remote desktop services are connected directly to the Internet. Instead place computers running remote desktop behind VPNs so that they are only accessible to those who have VPN accounts on your network.
It is also important to setup proper account lockout policies so that it makes it difficult for accounts to be brute forced over Remote Desktop Services.
You should also have security software that incorporates behavioral detections to combat ransomware and not just signature detections or heuristics. For example, Emsisoft Anti-Malware and Malwarebytes Anti-Malware both contain behavioral detection that can prevent many, if not most, ransomware infections from encrypting a computer.
Last, but not least, make sure you practice the following good online security habits, which in many cases are the most important steps of all:
For a complete guide on ransomware protection, you visit our How to Protect and Harden a Computer against Ransomware article.