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Decrypt .cry files virus and remove CryLocker ransomware

3 min read
The CryLocker ransomware, which appends .cry extension to encrypted files, impersonates an inexistent government organization and demands $625 for recovery.

The scourge of crypto malware is one of the few computer plagues that AV labs and the community of security experts have virtually no viable response for, although these infections have been around for years. The kernel component that’s nearly impossible to get around is encryption with symmetric or asymmetric cryptographic algorithms, where one’s files become locked and the only mechanism to unlock them is through obtaining a criminals-owned secret key. CryLocker, a new sample on the loose, appears to be flawless in terms of cipher implementation. At first sight, it looks like one of many suchlike extortion products, but some deeper insight reveals quite a few offbeat properties under its hood. First of all, some of the warning notifications are allegedly displayed on behalf of a mythical law enforcement entity called the “Central Security Treatment Organization”, in particular the department of pre-trial settlement.

CryLocker desktop wallpaper
CryLocker desktop wallpaper

The idea behind this deceit is to make the attack look like an attempt to help the victim evade prosecution for some framed-up cyber felony. Furthermore, the name and fancy logo displayed in the infected person’s User Cabinet are supposed to make such a deal more trustworthy. This, however, is nothing but a lame try to leverage social engineering and manipulate people into coughing up some money. If CryLocker is on board a Windows PC, it most likely got there through the use of the Sundown exploit kit, which means that the victim had surfed malicious or compromised websites prior to the breach. The exploit kit covertly harnesses vulnerabilities in unpatched software installed on the machine. Having made its way inside, the ransomware scans the hard drive for data, comparing every stored object against a predefined list of hundreds of popular file extensions. Every match is then subject to modification with the RSA cipher.

CryLocker User Cabinet with ransom payment options and deadline countdown
CryLocker User Cabinet with ransom payment options and deadline countdown

A conspicuous byproduct of this routine is the concatenation of the .cry extension at the end of filenames. Of course, it’s impossible to open these items as per the unbreakable RSA encryption. To instruct the victim what to do next, the Trojan creates the following files on the desktop: !Recovery_[6 random chars].txt and !Recovery_[6 random chars].html. It also replaces the desktop wallpaper with its own, which says, “Attention! All your files were encrypted by CryLocker!” The above-mentioned ransom notes contain the user’s unique ID and explain how to visit the Tor payment site.

Once the victim logs into their User Cabinet, they see a bunch of alerts, the size of the ransom, a digital clock counting down the time before the 4-day deadline expires. The commission for decryption is originally 1.13 Bitcoins, or 625 USD. In four days, this amount goes up to 2.27 Bitcoins. The Tor page also provides the test decryption option, but it appears to be unstable at this point. Since the encryption standard is too strong to brute force in this case, the only workarounds involve forensic techniques covered below.

Automated removal of CryLocker

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 .cry files 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.

Ways of non-ransom recovery of .cry files

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 the ransomware, 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 install the app and use its intuitive controls to get previous versions of the encrypted objects reinstated.
Shadow Explorer

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.

Download Data Recovery Pro

Data Recovery Pro

Ransomware Prevention Tips

To avoid the CryLocker 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.

Download CryLocker ransomware removal tool

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