The Fallout Exploit has been distributing the GandCrab Ransomware for the past few weeks, but has now switched its payload to the Kraken Cryptor Ransomware.
Kraken Cryptor is a Ransomware as a Service (RaaS) that is actively being distributed by affiliates. As this is an affiliate system, we are seeing different bad actors distributing the ransomware using a variety of methods. For example, last month a Kraken affiliate compromised the Superantispyware.com site and was distributing the ransomware as a fake installer for the SuperAntiSpyware security program.
The affiliate behind the SuperAntiSpyware compromise told BleepingComputer via email that they had originally planned on replacing the original SuperAntiSpyware.exe file with the ransomware executable, but for some reason never did it.
"Our plan that replace original file with our ransomware file. Not sure about other kids but we do this for more fun and little money."
Exploit kit expert nao_sec has told BleepingComputer in private conversations that the Fallout Exploit Kit started to distribute the Kraken Cryptor Ransomware earlier this week. First it started distributing version 1.5, which had an interesting comment of "EK Edition" in the ransomware's configuration.
Today, nao_sec told BleepingComputer that the exploit has started to distribute version 1.6, but as can be seen from the configuration, has removed the "EK Edition" comment found in the previous version.
Victims encounter the exploit kit by visiting compromised sites that redirect them through a series of gateways that ultimately land them on the page hosting the Fallout Exploit kit. You can see an example of these redirects in the Fiddler traffic below that was captured by Nao_sec. Fallout will then attempt to exploit the Windows CVE-2018-8174 VBScript vulnerability to install the ransomware.
Once the ransomware is installed, it will begin encrypting a victims files. Unlike previous versions which was using sequential numbers for the filename and then appending Lock.onion, this version will rename the encrypted files to a random name with a random extension.
For example, in our test it encrypted a file and renamed to a name like AaPeTejeKzqJZWlb.OCYAV.
While encrypting, the ransomware will also create ransom note named # How to Decrypt Files-[extension].html. This ransom note contains instructions on how to pay the ransom and contact the affiliate at firstname.lastname@example.org or BM-2cWdhn4f5UyMvruDBGs5bK77NsCFALMJkR@bitmessage.ch.
Unfortunately, at this time there is no way to decrypt encrypted files for free.
In order to protect yourself from Kraken Cryptor, 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.
Because Kraken is being installed via exploit kits, make sure you have all the latest Windows security updates installed and that your programs are updated to the latest versions. This will prevent exploit kits from using vulnerabilities to infect your computer.
As ransomware is also known to be 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.