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.
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.
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.
Automated removal of CryptoWall 4.0 ransomware
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
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.
Ways of non-ransom recovery of CryptoWall 4.0 encrypted data
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.
Backups can make your day
Not only are you a lucky person in case you’ve been backing up your most important files, but you’re also a wise and prudent user. This isn’t necessarily a resource-heavy activity these days – in fact, some providers of online services are allocating a sufficient size of cloud storage space for free so that every customer can easily upload their critical data without paying a penny. Having removed CryptoWall 4.0, therefore, all you have to do is download your stuff from the remote server or transfer it all from an external piece of hardware if that’s the case.
Restore previous versions of encrypted files
A positive upshot of using this technique depends on whether or not the ransomware has erased the Volume Shadow Copies of the files on your PC. This is a Windows feature that automatically makes and keeps the backups of data elements on the hard drive as long as System Restore is enabled. The cryptoware in question is programmed to switch off the Volume Shadow Copy Service (VSS), but it has reportedly failed to in some cases. Checking one’s options regarding this workaround is doable in two ways: through the Properties menu of each file or by means of the remarkable open-source tool called Shadow Explorer. We recommend the software-based way because it’s automated, hence faster and easier. Just launch the app and use its intuitive controls to get previous versions of the encrypted objects reinstated.
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 Data Recovery Pro by ParetoLogic features this type of capability therefore it can be applied in ransom attack scenarios to at least get the most important files back. So download and install the program, run a scan and let it do its job.
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.
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