Erebus ransomware infects Linux web servers in South Korea

Since the crypto ransomware called Erebus is professionally designed and currently cannot be cracked, it is shaping up to be another serious security problem.

There is no computer completely immune to ransomware. What is more, these threats are getting increasingly sophisticated over time. Even if one exercises due caution with files that go with malicious spam, there is always probability of crooks leveraging RDP or exploit kits that need a minimum of user action to deploy the bad program. A recent extortion hoax depositing the Erebus ransomware on Windows machines shows how efficient these campaigns can be. This sample has been circulating since February 2017, but it’s not until early June that a significant upswing in its distribution took root. Erebus is unusual in several ways. First of all, it is capable of getting around UAC (User Account Control) on an infected host. Secondly, in addition to encrypting files proper, it scrambles every file extension.

This strain is making the rounds by dint of spam generated by a large network of bots. The contagious emails may impersonate various local service providers, including ISPs, as well as international delivery companies, potential employers or even law enforcement agencies. Regardless of the email subject, the gist of the attack vector lies in the attachment. If opened, what looks like an innocuous invoice, job offer or scanned fax will unleash the infection behind the recipient’s back. As it has been mentioned, payload execution is followed by a UAC circumvention trick, where the bad code makes changes to the system registry in order to tweak certain file associations. This enables the ransomware process to run at elevated privileges without displaying any authorization prompts.

A number of media resources are unveiling some disconcerting details on the current Erebus outbreak. The ransomware reportedly hit a high-profile target around June 10, which has led to immense collateral damage. Nayana, a web hosting company based in South Korea, had 153 of its Linux servers contaminated with the crypto malware in question. Consequently, about 3,400 websites hosted on the hijacked servers got affected in the aftermath of this compromise. As per official coverage of this incident, the threat actors originally demanded a whopping 10 Bitcoin (about $27,000) for data decryption but ended up reducing it down to 5.4 Bitcoin, which is still a hefty amount. Nayana officials claim to be negotiating with the crooks at the time of this writing and have called in local authorities to investigate.

Once executed, the Erebus ransomware identifies files stored in the most popular data formats. The built-in list of these formats isn’t as broad as with most crypto infections, but it does cover the most potentially valuable information. Then, it encrypts the contents of every such file using AES (Advanced Encryption Standard), which makes it impossible to open or edit the data without the criminals-owned secret key. Additionally, Erebus jumbles up file extension through the use of ROT-23, a variant of the so-called Caesar cipher. Meanwhile, filenames are not altered. As a result, a sample spreadsheet named Receipt.xlsx will turn into an entry named Receipt.uipu.

Having completed the encryption, the Trojan displays a “Files crypted!” popup dialog. It reads, “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.” Indeed, the Erebus virus drops a troubleshooting how-to named README.html onto the desktop and into every directory with locked files. This ransom note includes unique victim ID, the list of hostage data entries, and a button leading to a Tor-based decryption service page. The latter instructs the victim to submit 0.085 Bitcoin (about $230) during 96 hours. This is a fairly small amount compared to other extortion waves, but that’s cold comfort anyway. No free decryption tool supports the Erebus ransomware at this time, so the data recovery techniques below are must-try.

Erebus ransomware automated removal and data recovery

When faced with ransomware like Erebus, one of the best shortcuts in terms of removal is to use Combo Cleaner, a lightweight and incredibly effective application with PC security and optimization features under the hood. It detects and thoroughly deletes threats while giving you insights into the overall health of your computer.

This program’s protection power spans modules that forestall all known types of malware, including ransomware and browser hijackers, and take your online security to the next level by blocking phishing sites and other suspicious web pages. Follow these simple steps to eliminate the infection for good:

1. Download Combo Cleaner installer.

Download Erebus remover

^{Combo Cleaner scans your PC with no strings attached, but you’ll have to buy its fully functional version to remove the threats it detects. The disk optimization tools that find large files and duplicates are free to use.}

2. Open the CCSetup.exe file to get started. Several subsequent screens will allow you to make initial customizations so that the program works exactly as you need from the get-go.

3. The installation will be followed by an update of malware signatures. Once this process is through, click the Start Scan button in the left-hand sidebar.

4. Combo Cleaner will then check system locations that are most often polluted by Windows malware. The first scan can take a while to finish.

5. Combo Cleaner will display a system tray notification as soon as the scan is over. Click the Resolve found threats button to view the results.

6. The scan summary shows the names and types of the detected threats as well as their statuses and locations. Click the Remove all threats button and follow further on-screen prompts to get rid of these items.

Data recovery toolkit to the rescue

Some strains of ransomware are known to delete the original files after the encryption routine has been completed. As hostile as this activity appears, it can play into your hands. There are applications designed to revive the information that was obliterated because of malfunctioning hardware or due to accidental removal. The tool called Stellar Data Recovery features this type of a capability and therefore it can be applied in ransom attack scenarios to at least get the most important files back. So use the app to get an idea of what data can be restored and let it do the recovery job. Here is a step-by-step walkthrough:

1. Download and install Stellar Data Recovery.

Download Stellar Data Recovery

2. Open the application, select the types of recoverable files to look for, and click Next.

3. Choose the areas you want the tool to recover from and click the Scan button.

4. Having scanned the specified locations, the program will display a notification about the total amount of recoverable data. Close the dialog and click the Recover button. This will hopefully help you get some of your valuable files back.

Erebus ransomware manual removal and file recovery

Some ransomware strains terminate themselves after completing the encryption job on a computer, but some don’t. Furthermore, the Erebus virus may prevent victims from using popular antimalware tools in order to stay on board for as long as possible. Under the circumstances, it may be necessary to utilize the Safe Mode with Networking or System Restore functionality.

Be advised that even after the ransomware is removed, files will still be encrypted and inaccessible. The malicious code cleanup part, however, is important because it keeps a relapse of the infection from occurring further on and eliminates all opportunistic malware.

Ways of non-ransom recovery of files encrypted by Erebus

Cracking the crypto used by this ransom Trojan is more of a science fiction thing rather than an attainable prospect for the masses. This is why the troubleshooting in predicaments of this sort is a matter of two approaches: one is to pay the ransom, which isn’t an option for many victims; and the other is to apply instruments that take advantage of the ransomware’s possible weaknesses. If the latter is your pick, the advice below is a must-try.

Ransomware Prevention Tips

To avoid Erebus ransomware and other file-encrypting infections in the future, follow several simple recommendations:

These techniques are certainly not a cure-all, but they will add an extra layer of ransomware protection to your security setup.

Revise your security status

Post-factum assessment of the accuracy component in malware removal scenarios is a great habit that prevents the comeback of harmful code or replication of its unattended fractions. Make sure you are good to go by running an additional safety checkup. Another benefit of using the antimalware tool is that it will keep ransomware threats from intruding on your computer further on.

Download Erebus removal tool