How to remove Erebus ransomware virus

Erebus Linux ransomware targets servers

Erebus ransomware is a malicious program that aims to compromise Linux systems and especially servers. Just like any other ransomware^[1], Erebus' primary goal is to corrupt as many machines as possible and demand an enormous ransom afterward.

The initial version of Erebus used RSA-2048 encryption, appended .ecrypt file extensions to files and leaved two files as ransom notes: YOUR_FILES_HAS_BEEN_ENCRYPTED.txt” and “YOUR_FILES_HAS_BEEN_ENCRYPTED.html. The virus was using hacked websites in South Korea as its Command and Control (C&C) servers. The version was able to encrypt over 423 different file types. 

The subsequent version of the ransomware was designed to bypass User Account Control (UAC) feature to launch itself with higher privileges. The virus stated that if the victim fails to comply with its demands and pay 0.085 BTC within 96 hours, the files stored on the computer will be deleted. The updated version of Erebus virus deleted victim's Volume Shadow Copies to prevent him from restoring encrypted files for free.

Although keeping a copy of personal files on an external storage device can help you to save part of your work in case of a ransomware attack, the majority of computer users do not feel the need to create them. Consequently, they have to sorrow over lost files later and desperately look for data recovery methods.

It doesn't matter whether you are a Windows, Mac or Linux user, you must take preventative measures to ward of malicious attacks. We suggest using software like FortectIntego or SpyHunterCombo Cleaner for ransomware removal. To remove Erebus, you must use a software that is compatible with Linux.

Update February 2017: Erebus improves, demands a smaller ransom

In February, cyber security experts noticed a new version of this virus that encrypts target files with AES encryption^[2] and then modifies their file extensions using ROT-23 cipher. After that, it saves the README.html file on the desktop. The file contains instructions on how to recover the files.

As common for this type of virus, it urges victims to pay within 96 hours. There has been a tendency among hackers to use single-use email addresses for contacting with the victims. However, there is too little information whether the cyber criminals respond to victims and transfer the files. If you have fallen into the trap of this ransomware as well, concentrate on Erebus removal.

Now the current edition bypasses User Account Control^[3] window, or in other words, disables the function which initiates dialogue boxes before installing a new program. Likewise, the cryptomalware deprives a victim of ceasing the infection manually. Besides, the virus modifies registry keys to accelerate its functionality.

The ransomware launches eventvwr.msc file, which then opens eventvwr.msc file. The EventViewer is no longer associated with mmc.exe file, therefore it launches a randomly entitled executable of the virus. Thanks to EventViewer's capabilities to run in elevated mode, the virus' executable will be launches with similar permissions.

Afterward, Erebus connects http://ipecho.net/plain and http://ipinfo.io/ to identify the geographical location of a user. Later on, the virus will also access Tor network and connect to its Command and Control server.

Do not underestimate the ransomware as it deletes shadow volume copies leaving fewer chances for its victims to recover data. At the moment, it demands quite a small amount of ransom – 0,85 BTC (90 USD). Lastly, it launches an additional message which once again informs users about the ransomware attack.

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

Update June 2017: Erebus malware strikes to South Korean web hosting company

Erebus successfully infected a web hosting company Nayana in South Korea^[4], which allowed the malware to compromise thousands of websites. The ransomware attack affected over hundred Linux servers and it seems that it encouraged the cybercriminals to demand for a ridiculously high ransom – 10 Bitcoins, which is nearly $26k. Later on, frauds realized that the ransom sum was too high and lowered it to 5.4 Bitcoin – approximately $14k.

The ransomware locked databases, images and videos. The company has published several notes on its official website, suggesting that it is sorry for the inconvenience and that legal authorities are investigating the case at the moment. In the meantime, Nayana employees are working hard to respond to customers and restore backup files provided by them. It is also known that the company is currently negotiating the ransom price with cyber criminals.

The notices posted on company's official website suggest that cybercriminals may have given the company quite a good discount – one of provided noticed contain a piece of message from cyber criminals, asking for 550 BTC. Frauds even provide a calculation proving that the company can pay it.

Distribution tricks

Unlike other ransomware infections, the virus concentrates on malvertising to deliver its attacks. Specifically, it works through ads which users carelessly click on. Afterward, they get redirected to the domain which is infected with RIG exploit kit ^[5].

Likewise, when a victim finds himself in such website, it becomes a matter of seconds until Erebus strikes. In order to avoid or at least lower the risk of a cyber attack, install a proper security program and let it deal with the virtual threat. It also comes in handy detecting such threats as trojans or smaller threats – hijackers.

Remove Erebus virus

In order to successfully remove Erebus virus, you will need a malware elimination utility. For that purpose, use practical tools that are compatible with Linux system. Keep in mind that they need to be updated in order for them to detect all components and registry entries of the threat.

After the elimination of Erebus, remember to follow safe browsing rules to prevent attackers from infecting your PC ever again. In the end, beware of spam emails since they also often happen to be harbingers of file-encrypting threats. By keeping updated software and cautiously surfing the Web, you might lower the risk not only of Erebus ransomware attack but other crypto-virus as well.