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New EREBUS Ransomware Virus (Restore Files)

This article aims to help you remove the newly released EREBUS ransomware and try to get the encrypted files with .grf, .msj and .sqj extensions back.

ROT-23 or the so-called Caesar mode has been used by a newly discovered ransomware, known as EREBUS. The virus uses this algorithm to replace data of important files on the computers infected by it. This data is then no longer openable, and the virus appends different file extensions to the files, for example, .grf, .msj, .sqj and several others. The virus then drops a ransom note, named README.html which explains to the user that the files are encrypted, and he or she has to pay to get them back. In case you have been infected by EREBUS ransomware, we recommend not to pay any ransom and read this article instead.

Threat Summary

Name

EREBUS

TypeRansomware
Short DescriptionUses “UAC bypass” type of attack to infect computers. Encrypts files and demands a ransom of 0.85 BTC.
SymptomsThe files are encrypted with different file extension corresponding to different set of files. A ransom note, named README.html is dropped that leads to a TOR-based web-page with instruction son how to pay BTC to get the files back.
Distribution MethodVia an Exploit kit, Dll file attack, malicious JavaScript or a drive-by download of the malware itself in an obfuscated manner.
Detection Tool See If Your System Has Been Affected by EREBUS

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Malware Removal Tool

User ExperienceJoin our forum to Discuss EREBUS.
Data Recovery ToolWindows Data Recovery by Stellar Phoenix Notice! This product scans your drive sectors to recover lost files and it may not recover 100% of the encrypted files, but only few of them, depending on the situation and whether or not you have reformatted your drive.

EREBUS Ransomware – Technical Analysis

EREBUS ransomware is believed to either be an evolved version of a previous virus, also having the same name but using the .ecrypt file extension when it encodes files. However, this specific ransomware is using multiple file extensions and has a completely different ransom note and source code, in comparison to the other version, also named Erebus.

EREBUS Ransomware – Infection Process

The infection by EREBUS ransomware is a unique process. The virus takes advantage of the .msc types of files which can be executable if configured in a malicious way. What EREBUS does is it hijacks critical MSC processes, related to User Account Control in Windows. One of those may be the process lusrmgr.msc which is crucal to the Local Users and Groups, but there are other critical .msc processes that may also be hijacked by this ransomware to cause a bypass and hence an infection:

Potentially affected .msc processes:
admgmt.msc, azman.msc, certmgr.msc ciadv.msc, comexp.msc, compmgmt.msc, devmgmt.msc, dfrg.msc, dhcpmgmt.msc, diskmgmt.msc, eventvwr.msc, fsmgmt.msc, gpedit.msc, ipaddrmgmt.msc, lusrmgr.msc, ntmsmgr.msc, ntmsoprq.msc, perfmon.msc , rsop.msc, secpol.msc , services.msc, tsmmc.msc, uddi.msc, wmimgmt.msc, winsmgmt.msc

The virus exploits the .msc situation further focusing of the Windows objects related to UAC via the Windows Registry Editor. The sub-keys in the registry editor which it may target are the following:

→ HKEY_CLASSES_ROOT\.msc
HKCU\Software\Classes\mscfile

The virus has also been reported by malware researchers to start the process of Event Viewer which will open the .msc file, called “eventvwr.msc”. This file has scripts which bypass the original files that the Event Viewer should execute upon starting, but instead the malicious EREBUS encryptor starts working in an obfuscated mode that bypasses defenses.

EREBUS Virus – File Encryption

When it comes to encrypting files, the virus first connects to multiple remote hosts, which have tracking technologies. These determine where are you located and what is your system and they may reveal more information as well.

The virus will also start scanning the computer which has been infected. It looks for the following types of files:

→ ‘.accdb’, ‘.arw’, ‘.bay’, ‘.cdr’, ‘.cer’, ‘.crt’, ‘.crw‘, ‘.dbf‘, ‘.dcr‘, ‘.der‘, ‘.dng‘, ‘.doc‘, ‘.docm‘, ‘.docx‘, ‘.dwg‘, ‘.dxf‘, ‘.dxg‘, ‘.eps‘, ‘.erf‘, ‘.indd‘, ‘.jpe‘, ‘.jpg‘, ‘.kdc‘, ‘.mdb‘, ‘.mdf‘, ‘.mef‘, ‘.mrw‘, ‘.nef‘, ‘.nrw‘, ‘.odb‘, ‘.odm‘, ‘.odp‘, . ‘ods‘, ‘.odt‘, ‘.orf‘, ‘.pdd‘, ‘.pef‘, ‘.pem‘, ‘.pfx‘, ‘.png,‘ ‘.ppt‘, ‘.pptm‘, ‘.pptx‘, ‘.psd‘, ‘.pst‘, ‘.ptx‘, ‘.raf‘, ‘.raw‘, ‘.rtf‘, ‘.rwl‘, ‘.srf‘, ‘.srw‘, ‘.txt‘, ‘.wpd‘, ‘.wps‘, ‘.xlk‘, ‘.xls‘, ‘.xlsb‘, ‘.xlsm‘, ‘.xlsx‘

For the encryption a ROT-23 mechanism is used, also known as Caesar encryption is used to replace bytes of the files with the AES encryption algorithm, making them, no longer able to be opened. The virus ads a different extension for each set of files, for example a .jpg image would become .msj and so on. The files appear like the following:

The EREBUS virus also does not forget to delete the shadow volume copies of the infected computer, to eliminate any chance of backups. This happens by executing the following command in Windows command prompt with a “/all”, “/quet” and then “exit” script.

EREBUS Ransomware – Post-Encryption Activity

After having already done the damage, this nasty virus makes sure the user knows of it’s presence, by dropping an .html file, named README.html. This file has the following ransom note:

The virus also displays a small pop-up box, named “Files crypted !”. The box has a similar message as well:

“Every important file on this computer was crypted. Please look on your document or desktop folder for a file called README.html for instructions on how to decrypt them.”

The virus also shows which files were encrypted in it’s ransom note and has a button that says “Recover my files” with a web link to it’s website on the Onion network (TOR):

Once a unique ID which is on the ransom note is entered, the EREBUS virus provides detailed instructions on how to pay the ransom:

“Your files are still Encrypted
Your files have been Encrypted and are unusable unless you purchase a decryption key. The key will be deleted in 96 hours.
You still have 95 hours 07 minutes 24 seconds before the key deletion, once the key is destroyed, you will not be able to recover your files
Pay via Bitcoin
To buy the private key (decryption key) and decryptor you will need some bitcoins.
Bitcoin is a currency, just like dollars and euros but entirely on the internet.
1 : Get a wallet
Just like In real life you need a wallet to hold your coins when you’ll buy them. We suggest https://blockchain.info/ it’s a website easy to use, you’ll be set in no time !
2 : Buy some bitcoins
Depending on your country you can buy tem using various ways(paypal/credit card/ cash etc).
Look at tthis website https://www.buybitcoinworldwide.com to find where to buy some or ust search on google yourself.
Note that one of the fastest and easiest way is via https://localbitcoins.com because you buy bitcoins directly to other people. You could have a meeting tomorrow and buy them using cash instantly
3 : Payment
You need to buy 0.085 btc (bitcoins) and send them to this addres: {crooks’ BITCOIN url}
Once you’ve paid, wait a bit. The process can take up to 24 hours for us to check the payment. Then, you will receive on this same page your private key and a link to the decryption program that will automatically decrypt all your files so you can use them as before
you still have 0.085 bitcoins left to pay”

Remove EREBUS Ransomware and Restore Encrypted Files

Malware experts advise removing this ransomware virus and backing up the encrypted files somewhere else.

One of the best methods to remove this malware is if you hunt down the files responsible for the encryption, the touched files and the Windows Registry keys yourself.

One way to do this is if you follow the removal instructions below. In case you do not have experience for that, do not worry. Malware analysts claim that the best way of removing EREBUS ransomware is via an advanced anti-malware program, which will make sure you perform the removal automatically and will protect your system in the future.

At this current moment, there is no decryption available for this specific ransomware. However, there are several alternative methods that you can try. They are located in step “2. Restore files encrypted by EREBUS” below and they are no guarantee for file restoration, but you may get some of the data back. In the meantime, you can track this web page for any updates on the situation or simply write in our assistance forum topic about Erebus ransomware.

Manually delete EREBUS from your computer

Note! Substantial notification about the EREBUS threat: Manual removal of EREBUS requires interference with system files and registries. Thus, it can cause damage to your PC. Even if your computer skills are not at a professional level, don’t worry. You can do the removal yourself just in 5 minutes, using a malware removal tool.

1. Boot Your PC In Safe Mode to isolate and remove EREBUS files and objects
2.Find malicious files created by EREBUS on your PC

Automatically remove EREBUS by downloading an advanced anti-malware program

1. Remove EREBUS with SpyHunter Anti-Malware Tool and back up your data
2. Restore files encrypted by EREBUS
Optional: Using Alternative Anti-Malware Tools

Vencislav Krustev

A network administrator and malware researcher at SensorsTechForum with passion for discovery of new shifts and innovations in cyber security. Strong believer in basic education of every user towards online safety.

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