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Recover .micro files encrypted by Cryptolocker (Crypt0l0cker) ransomware

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This post covers the latest edition of Cryptolocker ransom trojan that encrypts files on a computer and adds .micro extension to all personal files.

The malicious cryptoware industry features odd associations and interchangeability between ostensibly unrelated infection samples. Here’s an example of this trend: a new, third iteration of TeslaCrypt virus surfaced a few weeks ago, which uses unique infrastructure and supplements every encrypted file with specific extensions, namely .micro, .ttt or .xxx. Now, the most recent build of another trojan, Cryptolocker, has a code that’s written independently, but one of the symptoms is shared by the two. It also appends the filenames of documents, images and video items on infected computers with the .micro tail. This may hint at copycat activity, but it in no way makes the predicament any less complicated for the victims.

Cryptolocker main application instructing a victim on data recovery
Cryptolocker main application instructing a victim on data recovery

According to its warning window, Cryptolocker claims to employ RSA-4096 algorithm for encrypting data on the contaminated workstation. Expert analysis, however, proves that this statement is exaggerated as it actually uses RSA-2048, a standard based on generating keys with less entropy. Unfortunately, none of these is crackable with regular computation power, so it’s a huge problem for infected people one way or another. Having encoded data with the most widespread extensions on a PC or enterprise network, the ransomware displays a message starting with the following phrase: “Your important files were encrypted on this computer: photos, videos, documents, etc. You can verify this by (sic) click on see files and try to open them.

Desktop wallpaper accompanying the compromise
Desktop wallpaper accompanying the compromise

The anatomy of Cryptolocker attack includes the generation of a key pair: public and private. It’s the private key that is needed for recovering files. The problem is, the trojan sends this piece of data over to its C2 server, so it’s inaccessible for the user. The fee, which must be paid for retrieving it, is set to 0.5 Bitcoins, although the amount may be different for some variants. Furthermore, while the extortionists recommend crypto currency as the “cheapest” option, an alternative way is via prepaid vouchers such as Ukash.

The attacked users are provided with a deadline for making the payment, which is 72 hours (3 days) in most cases. The sum will increase if the victim doesn’t submit the fee on time. Another sort of interesting fact is that in the event the infected person ventures to remove the crypto malware proper, a desktop wallpaper shown by Cryptolocker will list steps to reinstall it and then retain the ability to pay and restore the .micro files.

Whereas the standard key-assisted recovery is the only effective method, there are other techniques that may be of help. The main virtue of this tactic is you don’t have to send the ransom, so try it now.

.micro file 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 .micro file 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 .micro file 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 .micro file ransomware removal tool

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