The article covers must-know facts about Cryptolocker, an advanced persistent Trojan that applies uncrackable RSA cipher to encode victims’ data.
It has been around three years since the first fully functional instances of encryption-based ransomware emerged. The threat landscape has changed considerably over this period, but some infections from this cluster stay and still thrive. The malicious program known as Cryptolocker typifies such an inviolability. Although it has gone through several critical ups and downs, its recurrent iterations never failed to hit the headlines due to the invariably large attack surface, unbeatable cryptographic grip on infected users’ personal files, and high success rate of payload serving. The way this crimeware deploys encryption is tricky as it actually leverages an amalgam of RSA and AES, thus leaving hardly any data recovery options for the assaulted person other than paying the ransom.
Incidentally, the recent edition of Cryptolocker mentions RSA-4096 asymmetric cipher on its warning screen, but this isn’t quite true. The entropy is in fact smaller as the keys are 2048 bits long, but it’s still enough to make the decryption vector of file recovery efforts null and void. Anyway, it takes this ransomware some time before it gets down to the crypto job proper. The first thing it does on a contaminated Windows computer is it adjusts the work of the host system in its own way by adding autostart values and disabling VSS (Volume Shadow Copy Service) to prevent easy file restoration. The next stage is a scan of all letter volumes both on the hard drive and the adjacent network if any. Unmapped network shares are not at risk.
Once the list of the victim’s personal files has been compiled, Cryptolocker triggers the encryption routine and makes them inaccessible. Some versions of the malware contort the appearance of files by modifying the filenames and adding bizarre extensions. It’s only at this point that the Trojan notifies the user of the attack. It displays a UI with a warning message and configures an image with ransom instructions to replace the original desktop wallpaper. According to the notifications, the victim has to pay 0.5-1 Bitcoin during 72 hours. The payment processing service is built into the program’s pane, so the person can navigate back and forth using the toggles provided.
Should the ransom not be submitted in time, the extortionists threaten the target to erase the private decryption key from their Command & Control server. In plain language, this means that the data will remain locked for good. Under certain circumstances, though, it may be possible to reanimate some files through the use of specially crafted recovery tools. Furthermore, Shadow Copies of some items may not be lost if the ransomware has failed to terminate the respective service. All in all, there might be a little bit of chance for remediation.
Automated removal of Cryptolocker 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 encrypted 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 Cryptolocker, 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.
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.