AES-128 Encryption Employed by Locky Ransomware

by Milena Dimitrova | February 17, 2016 | 0 Comments AES encryption, Locky ransomware, ransomware

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Locky ransomware is one of the latest, most devastating additions to the ransomware malware category. Locky uses the RSA algorithm mixed with AES-128 encryption ciphers, as stated in its ransom note. The combination creates a very strong encryption.

We have already analyzed RSA algorithms:

AES Encryption General Description

AES stands for Advanced Encryption Standard (AES). It is a symmetric encryption algorithm. The original name of the algorithm is Rijndael, based on the names of the two Belgian cryptographers who developed AES – Joan Daemen and Vincent Rijmen. Rijndael is a family of ciphers.

The AES itself is a specification for the encryption of electronic data established by the American National Institute of Standards and Technology (NIST) in 2001. The Institute selected three 128-bit ciphers of the Rijndael family for the AES standard. However, each of the three has different key lengths – 128, 192 and 256 (via Wikipedia).

AES is an encryption that is widely used in various business applications. However, crypto-malware has discovered a way to take advantage of it and use it against PC users.

Ransomware and AES Encryption

Many ransomware pieces have employed AES, in some cases combined with another type of encryption algorithm (such as RSA):

Locky Ransomware’s Encryption in Detail
In the case of Locky ransomware, a mixture of the RSA algorithm and AES-128 ciphers has been used, thus making the decryption process very challenging. Malware researchers are currently seeking ways to beat Locky’s encryption and help its victims retrieve their files.

Researchers at Palo Alto just revealed that Locky ransomware requires communication with a command & control server for a key exchange to take place, before the encryption process has started. The key exchange is performed in memory – a unique feature, as most ransomware pieces generate encryption key locally and randomly on the victim machine and then send it to the attackers’ infrastructure.

This unique feature also shows that Locky’s creators have employed a mitigation strategy by disrupting associated command & control servers.

In addition, Locky changes the filenames entirely. A file encrypted by Locky looks like that:

&rarr0AC07E962F87084DA6793732FA3D31B4.locky

During the encryption process, the ransomware uses the AES algorithm and will only encrypt files matching these extensions:

→.mid, .wma, .flv, .mkv, .mov, .avi, .asf, .mpeg, .vob, .mpg, .wmv, .fla, .swf, .wav, .qcow2, .vdi, .vmdk, .vmx, .gpg, .aes, .ARC, .PAQ, .tar.bz2, .tbk, .bak, .tar, .tgz, .rar, .zip, .djv, .djvu, .svg, .bmp, .png, .gif, .raw, .cgm, .jpeg, .jpg, .tif, .tiff, .NEF, .psd, .cmd, .bat, .class, .jar, .java, .asp, .brd, .sch, .dch, .dip, .vbs, .asm, .pas, .cpp, .php, .ldf, .mdf, .ibd, .MYI, .MYD, .frm, .odb, .dbf, .mdb, .sql, .SQLITEDB, .SQLITE3, .asc, .lay6, .lay, .ms11 (Security copy), .sldm, .sldx, .ppsm, .ppsx, .ppam, .docb, .mml, .sxm, .otg, .odg, .uop, .potx, .potm, .pptx, .pptm, .std, .sxd, .pot, .pps, .sti, .sxi, .otp, .odp, .wks, .xltx, .xltm, .xlsx, .xlsm, .xlsb, .slk, .xlw, .xlt, .xlm, .xlc, .dif, .stc, .sxc, .ots, .ods, .hwp, .dotm, .dotx, .docm, .docx, .DOT, .max, .xml, .txt, .CSV, .uot, .RTF, .pdf, .XLS, .PPT, .stw, .sxw, .ott, .odt, .DOC, .pem, .csr, .crt, .key, wallet.dat

As we already said, for now decryption of files encrypted by Locky is not possible. Nonetheless…

Make sure to learn more about Locky’s methods and technical details.

Also, if you have been infected by Locky ransomware, make sure to remove it from your system via anti-malware software.

Spy Hunter scanner will only detect the threat. If you want the threat to be automatically removed, you need to purchase the full version of the anti-malware tool.Find Out More About SpyHunter Anti-Malware Tool / How to Uninstall SpyHunter

Milena Dimitrova

An inspired writer and content manager who has been with SensorsTechForum for 4 years. Enjoys ‘Mr. Robot’ and fears ‘1984’. Focused on user privacy and malware development, she strongly believes in a world where cybersecurity plays a central role. If common sense makes no sense, she will be there to take notes. Those notes may later turn into articles!

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may remain persistent on your system and may re-infect it. We recommend you to download SpyHunter and run free scan to remove all virus files on your PC. This saves you hours of time and effort compared to doing the removal yourself.

Keep in mind, that SpyHunter’s scanner is only for malware detection. If SpyHunter detects malware on your PC, you will need to purchase SpyHunter’s malware removal tool to remove the malware threats. Read our SpyHunter 5 review. Click on the corresponding links to check SpyHunter’s EULA, Privacy Policy and Threat Assessment Criteria.

Preparation before removing .

Before starting the actual removal process, we recommend that you do the following preparation steps.

Make sure you have these instructions always open and in front of your eyes.
Do a backup of all of your files, even if they could be damaged. You should back up your data with a cloud backup solution and insure your files against any type of loss, even from the most severe threats.
Be patient as this could take a while.

Step 1: Boot Your PC In Safe Mode to isolate and remove

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Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!

We Recommend To Scan Your PC with SpyHunter

1. Hold Windows key() + R

2. The “Run” Window will appear. In it, type “msconfig” and click OK.

3. Go to the “Boot” tab. There select “Safe Boot” and then click “Apply” and “OK”.

Tip: Make sure to reverse those changes by unticking Safe Boot after that, because your system will always boot in Safe Boot from now on.

4. When prompted, click on “Restart” to go into Safe Mode.

5. You can recognise Safe Mode by the words written on the corners of your screen.

Step 2: Clean any registries, created by on your computer.

The usually targeted registries of Windows machines are the following:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

You can access them by opening the Windows registry editor and deleting any values, created by there. This can happen by following the steps underneath:

1. Open the Run Window again, type “regedit” and click OK.

2. When you open it, you can freely navigate to the Run and RunOnce keys, whose locations are shown above.

3. You can remove the value of the virus by right-clicking on it and removing it.

Tip: To find a virus-created value, you can right-click on it and click “Modify” to see which file it is set to run. If this is the virus file location, remove the value.

Step 3: Find files created by

For Windows 8, 8.1 and 10.

For Windows XP, Vista, and 7.

For Newer Windows Operating Systems

1: On your keyboard press  + R and write explorer.exe in the Run text box and then click on the Ok button.

2: Click on your PC from the quick access bar. This is usually an icon with a monitor and its name is either “My Computer”, “My PC” or “This PC” or whatever you have named it.

3: Navigate to the search box in the top-right of your PC’s screen and type “fileextension:” and after which type the file extension. If you are looking for malicious executables, an example may be “fileextension:exe”. After doing that, leave a space and type the file name you believe the malware has created. Here is how it may appear if your file has been found:

N.B. We recommend to wait for the green loading bar in the navination box to fill up in case the PC is looking for the file and hasn’t found it yet.

For Older Windows Operating Systems

In older Windows OS’s the conventional approach should be the effective one:

1: Click on the Start Menu icon (usually on your bottom-left) and then choose the Search preference.

2: After the search window appears, choose More Advanced Options from the search assistant box. Another way is by clicking on All Files and Folders.

3: After that type the name of the file you are looking for and click on the Search button. This might take some time after which results will appear. If you have found the malicious file, you may copy or open its location by right-clicking on it.

Now you should be able to discover any file on Windows as long as it is on your hard drive and is not concealed via special software.

IMPORTANT!
Before starting “Step 4”, please boot back into Normal mode, in case you are currently in Safe Mode.
This will enable you to install and use SpyHunter 5 successfully.

Step 4: Scan for with SpyHunter Anti-Malware Tool

1. Click on the “Download” button to proceed to SpyHunter’s download page.

Download

Malware Removal Tool

It is recommended to run a scan before purchasing the full version of the software to make sure that the current version of the malware can be detected by SpyHunter. Click on the corresponding links to check SpyHunter’s EULA, Privacy Policy and Threat Assessment Criteria.

2. After you have installed SpyHunter, wait for it to update automatically.

3. After the update process has finished, click on the ‘Malware/PC Scan’ tab. A new window will appear. Click on ‘Start Scan’.

4. After SpyHunter has finished scanning your PC for any files of the associated threat and found them, you can try to get them removed automatically and permanently by clicking on the ‘Next’ button.

If any threats have been removed, it is highly recommended to restart your PC.

Step 5 (Optional): Try to Restore Files Encrypted by .

Ransomware infections and aim to encrypt your files using an encryption algorithm which may be very difficult to decrypt. This is why we have suggested several alternative methods that may help you go around direct decryption and try to restore your files. Bear in mind that these methods may not be 100% effective but may also help you a little or a lot in different situations.

Method 1: Scanning your drive’s sectors by using Data Recovery software.
Another method for restoring your files is by trying to bring back your files via data recovery software. Here are some suggestions for preferred data recovery software solutions:

Method 2: Trying Kaspersky and EmsiSoft’s decryptors.
If the first method does not work, we suggest trying to use decryptors for other ransomware viruses, in case your virus is a variant of them. The two primary developers of decryptors are Kaspersky and EmsiSoft, links to which we have provided below:

Method 3: Using Shadow Explorer

To restore your data in case you have backup set up, it is important to check for Volume Shadow Copies, if ransomware has not deleted them, in Windows using the below software:

Shadow Explorer

Method 4: Finding the decryption key while the cryptovirus sends it over a network via a sniffing tool.

Another way to decrypt the files is by using a Network Sniffer to get the encryption key, while files are encrypted on your system. A Network Sniffer is a program and/or device monitoring data traveling over a network, such as its internet traffic and internet packets. If you have a sniffer set before the attack happened you might get information about the decryption key. See how-to instructions below:

Instructions on How to Find Decryption Key for Files Encrypted By Ransowmare

Milena Dimitrova

OFFER

REMOVE IT NOW (PC)

with Spy Hunter

Preparation before removing .

Before starting the actual removal process, we recommend that you do the following preparation steps.

Make sure you have these instructions always open and in front of your eyes.
Do a backup of all of your files, even if they could be damaged. You should back up your data with a cloud backup solution and insure your files against any type of loss, even from the most severe threats.
Be patient as this could take a while.

Step 1: Boot Your PC In Safe Mode to isolate and remove

OFFER

Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!

We Recommend To Scan Your PC with SpyHunter

1. Hold Windows key() + R

2. The “Run” Window will appear. In it, type “msconfig” and click OK.

3. Go to the “Boot” tab. There select “Safe Boot” and then click “Apply” and “OK”.

Tip: Make sure to reverse those changes by unticking Safe Boot after that, because your system will always boot in Safe Boot from now on.

4. When prompted, click on “Restart” to go into Safe Mode.

5. You can recognise Safe Mode by the words written on the corners of your screen.

Step 2: Clean any registries, created by on your computer.

The usually targeted registries of Windows machines are the following:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

You can access them by opening the Windows registry editor and deleting any values, created by there. This can happen by following the steps underneath:

1. Open the Run Window again, type “regedit” and click OK.

2. When you open it, you can freely navigate to the Run and RunOnce keys, whose locations are shown above.

3. You can remove the value of the virus by right-clicking on it and removing it.

Tip: To find a virus-created value, you can right-click on it and click “Modify” to see which file it is set to run. If this is the virus file location, remove the value.

Step 3: Find files created by

For Windows 8, 8.1 and 10.

For Windows XP, Vista, and 7.

For Newer Windows Operating Systems

1: On your keyboard press  + R and write explorer.exe in the Run text box and then click on the Ok button.

N.B. We recommend to wait for the green loading bar in the navination box to fill up in case the PC is looking for the file and hasn’t found it yet.

For Older Windows Operating Systems

In older Windows OS’s the conventional approach should be the effective one:

1: Click on the Start Menu icon (usually on your bottom-left) and then choose the Search preference.

2: After the search window appears, choose More Advanced Options from the search assistant box. Another way is by clicking on All Files and Folders.

Now you should be able to discover any file on Windows as long as it is on your hard drive and is not concealed via special software.

Step 4: Scan for with SpyHunter Anti-Malware Tool

1. Click on the “Download” button to proceed to SpyHunter’s download page.

Download

Malware Removal Tool

2. After you have installed SpyHunter, wait for it to update automatically.

3. After the update process has finished, click on the ‘Malware/PC Scan’ tab. A new window will appear. Click on ‘Start Scan’.

If any threats have been removed, it is highly recommended to restart your PC.

Milena Dimitrova

OFFER

REMOVE IT NOW (PC)

with Spy Hunter

Preparation before removing .

Before starting the actual removal process, we recommend that you do the following preparation steps.

Make sure you have these instructions always open and in front of your eyes.
Be patient as this could take a while.

Step 1: Uninstall and related software from Windows

OFFER

Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!

We Recommend To Scan Your PC with SpyHunter

Here is a method in few easy steps that should be able to uninstall most programs. No matter if you are using Windows 10, 8, 7, Vista or XP, those steps will get the job done. Dragging the program or its folder to the recycle bin can be a very bad decision. If you do that, bits and pieces of the program are left behind, and that can lead to unstable work of your PC, errors with the file type associations and other unpleasant activities. The proper way to get a program off your computer is to Uninstall it. To do that:

1. Hold the Windows Logo Button and “R” on your keyboard. A Pop-up window will appear.

2. In the field type in “appwiz.cpl” and press ENTER.

3. This will open a window with all the programs installed on the PC. Select the program that you want to remove, and press “Uninstall”

Follow the instructions above and you will successfully uninstall most programs.

Step 2: Clean your Browsers from .

Remove an extension from Mozilla Firefox

Remove an extension from Google Chrome

Remove an extension from Internet Explorer

Remove an extension from Microsoft Edge

1. Start Mozilla Firefox. Open the menu window

2. Select the “Add-ons” icon from the menu.

3. Select the unwanted extension and click “Remove“

4. After the extension is removed, restart Mozilla Firefox by closing it from the red “X” button at the top right corner and start it again.

1. Start Google Chrome and open the drop menu

2. Move the cursor over “Tools” and then from the extended menu choose “Extensions“

3. From the opened “Extensions” menu locate the unwanted extension and click on its “Remove” button.

4. After the extension is removed, restart Google Chrome by closing it from the red “X” button at the top right corner and start it again.

1. Start Internet Explorer:
2. Click on the gear icon labeled ‘Tools’ to open the drop menu and select ‘Manage Add-ons’

3. In the ‘Manage Add-ons’ window.

4. Select the extension you want to remove and then click ‘Disable’. A pop-up window will appear to inform you that you are about to disable the selected extension, and some more add-ons might be disabled as well. Leave all the boxes checked, and click ‘Disable’.

5. After the unwanted extension has been removed, restart Internet Explorer by closing it from the red ‘X’ button located at the top right corner and start it again.

1. Start Edge

2. Open the drop menu by clicking on the icon at the top right corner.

3. From the drop menu select “Extensions”.

4. Choose the suspected malicious extension you want to remove and then click on the gear icon.

5. Remove the malicious extension by scrolling down and then clicking on Uninstall.

Step 3: Clean any registries, created by on your computer.

The usually targeted registries of Windows machines are the following:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

You can access them by opening the Windows registry editor and deleting any values, created by there. This can happen by following the steps underneath:

1. Open the Run Window again, type “regedit” and click OK.

2. When you open it, you can freely navigate to the Run and RunOnce keys, whose locations are shown above.

3. You can remove the value of the virus by right-clicking on it and removing it.

Tip: To find a virus-created value, you can right-click on it and click “Modify” to see which file it is set to run. If this is the virus file location, remove the value.

Step 4: Scan for with SpyHunter Anti-Malware Tool

1. Click on the “Download” button to proceed to SpyHunter’s download page.

Download

Malware Removal Tool

2. After you have installed SpyHunter, wait for it to update automatically.

3. After the update process has finished, click on the ‘Malware/PC Scan’ tab. A new window will appear. Click on ‘Start Scan’.

If any threats have been removed, it is highly recommended to restart your PC.

Milena Dimitrova

OFFER

REMOVE IT NOW (MAC)

with Combo Cleaner

may remain persistent on your system and may re-infect it. We recommend you to download Combo Cleaner and run free scan to remove all virus files on your Mac. This saves you hours of time and effort compared to doing the removal yourself.

Combo Cleaner’s scanner is free but the paid version is needed to remove the malware threats. Read Combo Cleaner’s EULA and Privacy Policy

Preparation Phase:

Before starting to follow the steps below, be advised that you should first do the following preparations:

Backup your files in case the worst happens.
Make sure to have a device with these instructions on standy.
Arm yourself with patience.

Step 1: Uninstall and remove related files and objects

OFFER

Manual Removal Usually Takes Time and You Risk Damaging Your Files If Not Careful!

We Recommend To Scan Your Mac with Combo Cleaner

Keep in mind, that Combo Cleaner needs to purchased to remove the malware threats. Click on the corresponding links to check Combo Cleaner’s EULA and Privacy Policy

1. Hit the ⇧+⌘+U keys to open Utilities. Another way is to click on “Go” and then click “Utilities”, like the image below shows:

2. Find Activity Monitor and double-click it:

3. In the Activity Monitor look for any suspicious processes, belonging or related to :

Tip: To quit a process completely, choose the “Force Quit” option.

4. Click on the “Go” button again, but this time select Applications. Another way is with the ⇧+⌘+A buttons.

5. In the Applications menu, look for any suspicious app or an app with a name, similar or identical to . If you find it, right-click on the app and select “Move to Trash”.

6. Select Accounts, after which click on the Login Items preference. Your Mac will then show you a list of items that start automatically when you log in. Look for any suspicious apps identical or similar to . Check the app you want to stop from running automatically and then select on the Minus (“–“) icon to hide it.

7. Remove any left-over files that might be related to this threat manually by following the sub-steps below:

Go to Finder.
In the search bar type the name of the app that you want to remove.
Above the search bar change the two drop down menus to “System Files” and “Are Included” so that you can see all of the files associated with the application you want to remove. Bear in mind that some of the files may not be related to the app so be very careful which files you delete.
If all of the files are related, hold the ⌘+A buttons to select them and then drive them to “Trash”.

Step 2: Remove – related extensions from your Mac’s browsers

Remove a toolbar from Mozilla Firefox

Remove a toolbar from Google Chrome

Remove an extension from Safari and reset it.

1. Start Mozilla Firefox. Open the menu window

2. Select the “Add-ons” icon from the menu.

3. Select the Extension and click “Remove“

4. After the extension is removed, restart Mozilla Firefox by closing it from the red “X” in the top right corner and start it again.

1. Start Google Chrome and open the drop menu

2. Move the cursor over “Tools” and then from the extended menu choose “Extensions“

3. From the opened “Extensions” menu locate the add-on and click on the garbage bin icon on the right of it.

4. After the extension is removed, restart Google Chrome by closing it from the red “X” in the top right corner and start it again.

1. Start Safari

2. After hovering your mouse cursor to the top of the screen, click on the Safari text to open its drop down menu.

3. From the menu, click on “Preferences“

4. After that, select the ‘Extensions’ Tab

5. Click once on the extension you want to remove.

6. Click ‘Uninstall’

A pop-up window will appear asking for confirmation to uninstall the extension. Select ‘Uninstall’ again, and the will be removed.

How to Reset Safari
IMPORTANT: Before resetting Safari make sure you back up all your saved passwords within the browser in case you forget them.

Start Safari and then click on the gear leaver icon.

Click the Reset Safari button and you will reset the browser.

Step 3: Scan for and remove files from your Mac

When you are facing problems on your Mac as a result of unwanted scripts and programs such as , the recommended way of eliminating the threat is by using an anti-malware program. Combo Cleaner offers advanced security features along with other modules that will improve your Mac’s security and protect it in the future.

Download

Combo Cleaner