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Remove SkidLocker Ransomware and Restore .locked Files

encrypted-files-.locked-SkidLockerRansomware, going by the name SkidLocker has been reported to threaten users that they will never see their files again unless they make a payoff to cyber-criminal. The ransom payment amount which SkidLocker demands to decrypt the files it encodes is ~0.5 BTC which is around 250 US dollars. What is more, this crypto virus uses AES encryption algorithm to encode the files of infected users. After doing so, SkidLocker ads the .locked file extension to the encrypted files. Users are left with no choice but to pay the ransom with no guarantee their files will be restored back.
However, we strongly advise against paying any ransom money to decrypt your files to any ransomware, not just SkidLocker. This is because there is no guarantee you will receive your files back and furthermore, you support the cyber-criminals to further develop their ransomware.

Threat Summary

Name

SkidLocker

Type Ransomware
Short Description The malware encrypts files with a strong AES algorithm and uses RSA cipher to encrypt the key for decryption.
Symptoms The user may witness his wallpaper changed and unfamiliar files on his desktop. READ_IT.txt appears as a ransom note text file..
Distribution Method Via an Exploit kit.
Detection Tool See If Your System Has Been Affected by SkidLocker

Download

Malware Removal Tool

User Experience Join our forum to Discuss SkidLocker Ransomware.

SkidLocker Ransomware – Distribution Strategy

In order to infect users successfully SkidLocker`s creators may use different types of distribution methods to reach the end user.

They may conduct massive spam campaigns that resemble reputable services like PayPal, eBay, different banks, BestBuy and other services. The messages often feature malicious URLs that may lead to the automatic execution of a .js(JavaScript) file or even an Exploit Kit infection.

Another campaign that may be used to distribute SkidLocker is extremely shady websites or compromised legitimate sites. Such sites may have malicious executables put instead of setups of original software that the user might believe he or she is downloading.

The ransomware may also be distributed wherever you meet malicious URLs – forums, social media like Facebook, twitter and other. Such links, however are a bit tricky to place because, the cyber-criminals need to make them undetectable by the malware filters of the website. One way is to make the web links bounce through several hosts until the user lands on the malicious URL.

SkidLocker Ransomware – Technical Analysis

After infection, SkidLocker has been reported to create the following files:

In C:\Users\{Username}\Desktop:
ransom.jpg
WindowsUpdate.bat
READ_IT.txt
In C:\Users\{Username}:
Decrypter.exe

After doing so, the ransomware is able to successfully encrypt files using not just one but two encryption algorithms:

  • AES to encrypt the files.
  • RSA to encrypt the decryption password of the AES encrypted files

The ransomware is pre-programmed to look for the following file types and encode them:

→ .txt, .doc, .docx, .xls, .xlsx, .pdf, .pps, .ppt, .pptx, .odt, .gif, .jpg, .png, .db, .csv, .sql, .mdb, .sln, .php, .asp, .aspx, .html, .xml, .psd, .frm, .myd, .myi, .dbf, .mp3, .mp4, .avi, .mov, .mpg, .rm, .wmv, .m4a, .mpa, .wav, .sav, .gam, .log, .ged, .msg, .myo, .tax, .ynab, .ifx, .ofx, .qfx, .qif, .qdf, .tax2013, .tax2014, .tax2015, .box, .ncf, .nsf, .ntf, .lwp

Researchers at Nyxbone have also established that the ransomware executes a so-called “CreatePassword” command to encrypt the files with an AES cipher and use a unique 32 character alpha-numerical password for deciphering them.

After doing so, SkidLocker ransomware uses a very strong RSA cipher to encrypt the AES key file. It executes a “EncryptTextRSA” and “RSAENcrypt” commands to conduct the encryption.

Finally after it encrypts the files, the .locked file extension is added, for example:

→ Picture.jpg.locked

The ransomware is also reported to establish an active connection with the server 23.227.199.83 which is believed by researchers to be the command and control center of the virus. When Nyxbone checked the index of the server, the following files appeared, suggesting that other malware may also be distributed in association with this server:

SkidLocker-index-server-sensorstechforum-nyxboneSource: nyxbone.com

This server may also be used to send the encryption key in a RSA encrypted form to the cyber-criminals, so that they are successfully able to extort users with it. After this is done, the ransomware then changes the wallpaper using the image “ransom.jpg” it created:

SkidLocker-wallpaper-sensrorstechforum

The ransomware also drops a READ_IT.txt file which has the following ransom message:

→ “(If you are in Notepad, please click the Format menu above ^^^^ and click Word Wrap)
Uh oh. It looks like your data has been the victim of the encryption thief. Your files have been encrypted with AES: search your drive for “locked” if you don`t believe me. Unfortunately you’re going to have to pay some money to get your files back and your fee is approximately $200 in US Dollars. I`ll get right to the ugly details for that:
*You have 72 hours to make this happen as of {date} {time}. Otherwise, your files are lost for good. I will delete the necessary code for all time and I don`t even have to revisit your machine to do it.
*You will be paying by Bitcoin. Don`t worry, it is easy to figure out. Your fee is 0.500639 BTC. Pay this amount precisely, or I might not know who it was that paid in order to rescue them.
*Use LocalBitcoins.com. It isn`t hard to user, there are numerous ways to pay for my bitcoins on there and most importantly, it is fast. Did I mention you have 72 hours?
*The address you will be sending the bitcoins to is {Cyber-criminal’s bitcoin address}.
*Then you will wait for me to get the unlock code for you. Your code will be shown here, http://let-me-help-you-with-that.webnode.com/, under the amount you paid. This may take a day or so: you are on my schedule now 😛
*Once you have the code, you can unlock your files as follows:
***Go to your Start Menu
***In the search field, type “cmd”
***Right-click the cmd program.
***Click Run As Administrator(doesn`t have to be but files might be missed otherwise)
***Click Yes to allow it to run like that
***Type “cd C:\Users\{Username}
***Type “Decrypter.exe
*** Other people’s codes will not work for you, obviously.
That is basically it. The rest of this document is a further description about your situation.
*You’ll never be able to find me. Police will never be able to find me. Go ahead and try them if you like, but don`t expect your data back. They will be concerned about helping the community not with helping you meed your deadline. If they say they need to keep your desktop for a few days well lol, you probably won`t be seeing your machine again soon, let alone your data. I`ve been doing this for five years now and haven`t been caught yet.
*Best Buy will have no ability to undo the encryption. Hell, even the NSA probably couldn`t undo it. Well, maybe they could, but I suspect you won`t be a high priority for their computation clusters for at least a couple of years.
*In 72 hours, you will never be able to get these files open. I don`t much like people struggling against the powerful and there is no way for you to argue for an extension. Just make it happen.
So just be thankful that it wasn’t worse. I could have asked for more money. I could have been working for ISIS and saving that money to behead children. I could have been a mean SOB and just destroyed your data outright. Am I those things? No. I just need the money to live off (true story) and don`t care at all about the hacker “community”. So there isn’t anyone you will be protecting by sacrificing yourself. I’ll just encrypt more people’s data to make up for the loss.
So you have your instructions. I’ll even tell you how you could have prevented this.
*Install a good antivirus and keep it up to date. This is basically where you fell down.
* Don`t click on any file from the internet that isn`t a piece of data like (jpg, txt, doc) or you better really know where that file came from.
* Back up your files in case the encryption thief visits you. 😛
Better luck to you in the future.”

There is nothing more to say about this ransomware, as it is mentioned in its ransom note. However, malware researchers and security experts strongly advise against paying the ransom money, because:

  • You help the cyber-crook further spread the malware.
  • You may not get your files back and they may want more money later on.
  • Researchers may discover a decryption possibility by analyzing flaws in the malware itself with time.
  • There are alternative methods of restoring even a small portion of the data.
  • Your files will not be deleted they will just stay encrypted until a reliable decryption is created.

Remove SkidLocker Ransomware and Restore .locked Files

To remove SkidLocker, you should simply follow the step-by-step instructions which are posted below. We strongly advise you to install an advanced anti-malware program because it will automatically detect and remove the ransomware without damaging the encrypted files and protect you in the future from such.

To try and restore files encrypted by SkidLocker, you may want to use the alternative file restoration methods posted in step “3. Restore files encrypted by SkidLocker” below. They may not be 100 percent effective but they could help you revert even a small portion of the data.

Manually delete SkidLocker from your computer

Note! Substantial notification about the SkidLocker threat: Manual removal of SkidLocker requires interference with system files and registries. Thus, it can cause damage to your PC. Even if your computer skills are not at a professional level, don’t worry. You can do the removal yourself just in 5 minutes, using a malware removal tool.

1. Boot Your PC In Safe Mode to isolate and remove SkidLocker files and objects
2. Find malicious files created by SkidLocker on your PC
3. Fix registry entries created by SkidLocker on your PC

Automatically remove SkidLocker by downloading an advanced anti-malware program

1. Remove SkidLocker with SpyHunter Anti-Malware Tool
2. Back up your data to secure it against infections and file encryption by SkidLocker in the future
3. Restore files encrypted by SkidLocker
Optional: Using Alternative Anti-Malware Tools

Vencislav Krustev

A network administrator and malware researcher at SensorsTechForum with passion for discovery of new shifts and innovations in cyber security. Strong believer in basic education of every user towards online safety.

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