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Remove CryptoWall 4.0 ransomware virus and recover encrypted files

3 min read
Learn how to decode the files encrypted by CryptoWall 4.0, a new generation ransomware that uses advanced AV bypassing techniques and strong encryption.

The recently spotted circulation of the news-making CryptoWall file-encoding malware’s remake has once again accentuated the multimillion-dollar security industry’s helplessness in combatting these attacks. This is the fourth known iteration of this trojan, with the first samples having surfaced about a year ago. The tweaking of malign features in CryptoWall 4.0 version is significant enough for experts to state it is a revolutionary upgrade that now addresses some of the previously uncloaked weak links in the operation of this ransomware. So, it’s time to get into some detail. The malicious code dropper has become more sophisticated in the context of evading detection and blocking on the firewall as well as the antivirus end. The ransom information presented to victims has transformed into a different-named document as compared to the forerunner: it’s called HELP_YOUR_FILES, with the TXT, HTML and PNG variants around.

Ransom instructions in HELP_YOUR_FILES.TXT document
Ransom instructions in HELP_YOUR_FILES.TXT document

Due to a system startup interference routine, the above-mentioned message is displayed once the user logs on to Windows. It sneeringly says “Congratulations!!! You have become a part of large community #Cryptowall”, providing answers to the common questions asked by victims and also containing a user-specific ‘Personal Code’ to kick off with the decryption. The trojan still uses the same algorithm to encode personal files on the hard drive, namely the public-key RSA-2048 cryptosystem. A major hurdle to recovery attempts when it comes to the 4.0 version is that the infection encrypts all filenames along with their contents proper, making the targeted people yet more confused because they can hardly tell which file a specific object represents. Overall, the unaltered workflow followed by the virus is it scans all letter assigned volumes of the HDD as well as removable and mapped drives, encrypts the items that it deems personal based on their extensions, and keeps displaying windows with instructions on further action with regard to decryption.

The no longer accessible user files encrypted by CryptoWall 4.0
The no longer accessible user files encrypted by CryptoWall 4.0

One more concern about this upgrade is about the distribution part of the ransomware infrastructure. Not only does CryptoWall 4.0 rely on social engineering maneuvers involving harmful email attachments, but it reportedly gets also delivered to PCs via the Nuclear exploit kit. This way, the process is more obfuscated and harder to thwart. Furthermore, the virus reaches out to an array of compromised sites, including frc-pr(dot)com, tuvestir(dot)com and quite a few others, thus making the PC join a botnet used to contaminate other machines.

CryptoWall 4.0 connects to its command and control server through Tor gateways. Its extortion presupposes that the victims make payments in Bitcoins, with the sum currently being a little under 2 BTC, or around 700 USD. Recovery of the captured files via paying up to the crime actors is a thimblerig, but sometimes there is hardly any other option left. Study the remediation part of the present guide to learn what else you can do.

CryptoWall 4.0 ransomware automated removal and data recovery

Owing to an up-to-date database of malware signatures and intelligent behavioral detection, the recommended software can quickly locate the infection, eradicate it and remediate all harmful changes. So go ahead and do the following:

1. Download and install the antimalware tool. Open the solution and have it check your PC for PUPs and other types of malicious software by clicking the Start Computer Scan button

Download CryptoWall 4.0 virus remover

2. Rest assured the scan report will list all items that may harm your operating system. Select the detected entries and click Fix Threats to get the troubleshooting completed.

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.Stellar Data Recovery main screen

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

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.Recover files

Ransomware Prevention Tips

To avoid CryptoWall 4.0 ransomware and other file-encrypting infections in the future, follow several simple recommendations:

  • Toggle your email provider’s anti-spam settings to filter out all the potentially harmful incoming messages. Raising the bar beyond the default protection is an important countermeasure for ransom Trojans
  • Define specific file extension restrictions in your email system. Make sure that attachments with the following extensions are blacklisted: .js, .vbs, .docm, .hta, .exe, .cmd, .scr, and .bat. Also, treat ZIP archives in received messages with extreme caution
  • Rename the vssadmin.exe process so that ransomware is unable to obliterate all Shadow Volume Copies of your files in one shot
  • Keep your Firewall active at all times. It can prevent crypto ransomware from communicating with its C&C server. This way, the threat won’t be able to obtain cryptographic keys and lock your files
  • Back up your files regularly, at least the most important ones. This recommendation is self-explanatory. A ransomware attack isn’t an issue as long as you keep unaffected copies of your data in a safe place
  • Use an effective antimalware suite. There are security tools that identify ransomware-specific behavior and block the infection before it can do any harm.

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 CryptoWall 4.0 ransomware removal tool

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