ASN1 Ransomware

What is ASN1?

First discovered by MalwareHunterTeam, ASN1 is a ransomware-type virus that stealthily infiltrates the system and encrypts stored files. Cyber criminals spread ASN1 via spam emails (malicious attachments). Following infiltration, ASN1 encrypts files using asymmetric cryptography, unlike other ransomware-type viruses, it does not rename encrypted files or append extensions.

Following successful encryption, ASN1 opens a pop-up window and creates an HTML file ("!!!!!readme!!!!!.html"), placing it in each folder containing encrypted files.

The pop-up and HTML files contain an identical ransom-demand message stating that files are encrypted, and encouraging victims to visit a Tor website. The website contains a message stating that a ransom of 1 Bitcoin (currently, 1 Bitcoin is equivalent to ~$735) must be paid. Victims will then supposedly be provided with a private key used to decrypt their files.

The payment must be submitted with five days, otherwise decryption keys are deleted permanently. Be aware that files encrypted using asymmetric cryptography can only be restored using a private key. Criminals store this key on a remote server and attempt to trick victims into paying for it.

Be aware, however, that cyber criminals often ignore victims, despite submitted payments. Therefore, you are strongly advised to ignore all requests to pay. It is highly probable that paying will not deliver any positive result  and you will simply be scammed.

Furthermore, you will support their malicious businesses. Unfortunately, there are no tools capable of restoring files encrypted by ASN1 ransomware. Therefore, you can only restore your files/system from a backup.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

Updated ASN1 ransomware pop-up message:

ASN1 shares similarities with dozens of other ransomware-type viruses such as *.zzzzz, Shade, Locky, etc. All encrypt files and make ransom demands. There are just two noticeable differences: 1) type of cryptography (symmetric/asymmetric) used, and; 2) cost of decryption.

Ransomware is often distributed via third party software download sources (torrents, freeware download websites, free file hosting websites, etc.), infectious files attached to spam emails, fake software update tools, and trojans. Therefore, never download software from unofficial sources or open files received from suspicious/unrecognizable email addresses.

Cyber criminals are capable of exploiting software bugs/flaws to infect the system - for this reason, keep your installed applications up-to-date and use a legitimate anti-virus/anti-spyware suite. The key to computer safety is caution.

Screenshot of ASN1 HTML file:

Text presented within ASN1 pop-up and HTML file:

ALL YOUR FILES WERE ENCRYPTED!
1. Download and install TOR browser (recommended) or use your standard browser.
2. Follow the link that was generated for you.
3. On the next page you will see a Bitcoin wallet to pay, after you pay, you will get the key for decrypting your files.
4. Highlight (CTRL + A) and copy (CTRL + C) the key in clipboard, decoding will start.
5. Please, do not open files during decryption - opened files can not be decrypted.

Updated ASN1 .html ransom demanding file:

Text presented in this file:

Your computer is under attack. Each file has been encrypted. In order to restore them, please read the following instruction.
What do you need to know?
. You can not restore the files by yourself without our assistance. 1024 bit encryption key has been used. All files encrypted with TripleDES algorithm.
. We guarantee complete recovery. To prove it, you can choose any file in your computer and we can easily decrypt it.
. An interference into the process will lead to the data loss. We highly recommend you not to open the important files and we can not be held responsible for them.
What are you supposed to do in order to decrypt the system?
1. Download and install the TOR browser. The link can be obtained by clicking on the button "COPY LINK(Download TOR browser)".
t will take about 5 minutes to install it as any other browser.
2. Open the personal page in the TOR browser.
ou can get the link by clicking on the button "COPY LINK(Personal Link)".
3. On the personal page you can see an unique BitCoin wallet and the amount you are supposed to deposit.
itCoin is popular e-currency. There are more than 100 different ways you can buy BitCoin .
4. Deposit the required amount to BitCoin wallet.
nce payment is received and confirmed, your private key will appear on the page.
5. Copy paste the private key. Decoding process will start automatically.
elect the private key and then press "CTRL + C".
6. On the personal page you can ask for help in customer service.
ATTENTION!
or decryption our application must be running. If you do not see this text, so antivirus removed the application. Download and install it again on the personal page.
make sure to save the link for your personal page.
PERSONAL PAGE

Screenshot of ASN1 website:

Text presented within ASN1 website:

Your files were encrypted!
1(0) BTC -> 1QBrNs96QUFXaU22SJh77RSVQkdqyxwBDb (4:23:59:49)
For getting decryption key you must to pay amount, written above, to bitcoin address, written above. Amount in brackets indicates already paid amount. For buy bitcoin online, google it now. This page will refreshed every 120 seconds. If you already paid, please, wait for page refreshing.
If sofware was deleted, download it now . Absense of payment during next five days will double amount.
Chat with support now

Updated Tor website:

Text presented in this site:

Personal page
Remaining time is: 1:23:54:33 (after the time is expired, the required amount will be increased in 2 times)
The bitcoins left to be paid: 0.5 BTC
The wallet for the payment: 1BWxxj3QBZVpsXGuwY5ScnCkY5idTsXfop
ANY ATTEMPT TO REMOVE OR DAMAGE THIS CRYPTOLOCKER will lead to the loss of the private key and to the loss of your files.
To make sure that the files can be decrypted, you can decrypt any of the encrypted files for free.
To decrypt the file, follow the link Chat with support.
In the opened window click the Browse button, select the file to decrypt and click Send.
When you upload the page again, you will receive the link for downloading the decrypted file.
Download cryptolocker
Chat with support

Screenshot of files encrypted by ASN1:

ASN1 ransomware removal:

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Video suggesting what steps should be taken in case of a ransomware infection:

Quick menu:

• What is asn1 virus?
• STEP 1. Reporting ransomware to authorities.
• STEP 2. Isolating the infected device.
• STEP 3. Identifying the ransomware infection.
• STEP 4. Searching for ransomware decryption tools.
• STEP 5. Restoring files with data recovery tools.
• STEP 6. Creating data backups.

Reporting ransomware to authorities:

If you are a victim of a ransomware attack we recommend reporting this incident to authorities. By providing information to law enforcement agencies you will help track cybercrime and potentially assist in the prosecution of the attackers. Here's a list of authorities where you should report a ransomware attack. For the complete list of local cybersecurity centers and information on why you should report ransomware attacks, read this article.

List of local authorities where ransomware attacks should be reported (choose one depending on your residence address):

•  USA - Internet Crime Complaint Centre IC3
•  United Kingdom - Action Fraud
•  Spain - Policía Nacional
•  France - Ministère de l'Intérieur
•  Germany - Polizei
•  Italy - Polizia di Stato
•  The Netherlands - Politie
•  Poland - Policja
•  Portugal - Polícia Judiciária

Isolating the infected device:

Some ransomware-type infections are designed to encrypt files within external storage devices, infect them, and even spread throughout the entire local network. For this reason, it is very important to isolate the infected device (computer) as soon as possible.

Step 1: Disconnect from the internet.

The easiest way to disconnect a computer from the internet is to unplug the Ethernet cable from the motherboard, however, some devices are connected via a wireless network and for some users (especially those who are not particularly tech-savvy), disconnecting cables may seem troublesome. Therefore, you can also disconnect the system manually via Control Panel:

Navigate to the "Control Panel", click the search bar in the upper-right corner of the screen, enter "Network and Sharing Center" and select search result:

Click the "Change adapter settings" option in the upper-left corner of the window:

Right-click on each connection point and select "Disable". Once disabled, the system will no longer be connected to the internet. To re-enable the connection points, simply right-click again and select "Enable".

Step 2: Unplug all storage devices.

As mentioned above, ransomware might encrypt data and infiltrate all storage devices that are connected to the computer. For this reason, all external storage devices (flash drives, portable hard drives, etc.) should be disconnected immediately, however, we strongly advise you to eject each device before disconnecting to prevent data corruption:

Navigate to "My Computer", right-click on each connected device, and select "Eject":

Step 3: Log-out of cloud storage accounts.

Some ransomware-type might be able to hijack software that handles data stored within "the Cloud". Therefore, the data could be corrupted/encrypted. For this reason, you should log-out of all cloud storage accounts within browsers and other related software. You should also consider temporarily uninstalling the cloud-management software until the infection is completely removed.

Identify the ransomware infection:

To properly handle an infection, one must first identify it. Some ransomware infections use ransom-demand messages as an introduction (see the WALDO ransomware text file below).

This, however, is rare. In most cases, ransomware infections deliver more direct messages simply stating that data is encrypted and that victims must pay some sort of ransom. Note that ransomware-type infections typically generate messages with different file names (for example, "_readme.txt", "READ-ME.txt", "DECRYPTION_INSTRUCTIONS.txt", "DECRYPT_FILES.html", etc.). Therefore, using the name of a ransom message may seem like a good way to identify the infection. The problem is that most of these names are generic and some infections use the same names, even though the delivered messages are different and the infections themselves are unrelated. Therefore, using the message filename alone can be ineffective and even lead to permanent data loss (for example, by attempting to decrypt data using tools designed for different ransomware infections, users are likely to end up permanently damaging files and decryption will no longer be possible even with the correct tool).

Another way to identify a ransomware infection is to check the file extension, which is appended to each encrypted file. Ransomware infections are often named by the extensions they append (see files encrypted by Qewe ransomware below).

This method is only effective, however, when the appended extension is unique - many ransomware infections append a generic extension (for example, ".encrypted", ".enc", ".crypted", ".locked", etc.). In these cases, identifying ransomware by its appended extension becomes impossible.

One of the easiest and quickest ways to identify a ransomware infection is to use the ID Ransomware website. This service supports most existing ransomware infections. Victims simply upload a ransom message and/or one encrypted file (we advise you to upload both if possible).

The ransomware will be identified within seconds and you will be provided with various details, such as the name of the malware family to which the infection belongs, whether it is decryptable, and so on.

Example 1 (Qewe [Stop/Djvu] ransomware):

Example 2 (.iso [Phobos] ransomware):

If your data happens to be encrypted by ransomware that is not supported by ID Ransomware, you can always try searching the internet by using certain keywords (for example, a ransom message title, file extension, provided contact emails, crypto wallet addresses, etc.).

Search for ransomware decryption tools:

Encryption algorithms used by most ransomware-type infections are extremely sophisticated and, if the encryption is performed properly, only the developer is capable of restoring data. This is because decryption requires a specific key, which is generated during the encryption. Restoring data without the key is impossible. In most cases, cybercriminals store keys on a remote server, rather than using the infected machine as a host. Dharma (CrySis), Phobos, and other families of high-end ransomware infections are virtually flawless, and thus restoring data encrypted without the developers' involvement is simply impossible. Despite this, there are dozens of ransomware-type infections that are poorly developed and contain a number of flaws (for example, the use of identical encryption/decryption keys for each victim, keys stored locally, etc.). Therefore, always check for available decryption tools for any ransomware that infiltrates your computer.

Finding the correct decryption tool on the internet can be very frustrating. For this reason, we recommend that you use the No More Ransom Project and this is where identifying the ransomware infection is useful. The No More Ransom Project website contains a "Decryption Tools" section with a search bar. Enter the name of the identified ransomware, and all available decryptors (if there are any) will be listed.

Restore files with data recovery tools:

Depending on the situation (quality of ransomware infection, type of encryption algorithm used, etc.), restoring data with certain third-party tools might be possible. Therefore, we advise you to use the Recuva tool developed by CCleaner. This tool supports over a thousand data types (graphics, video, audio, documents, etc.) and it is very intuitive (little knowledge is necessary to recover data). In addition, the recovery feature is completely free.

Step 1: Perform a scan.

Run the Recuva application and follow the wizard. You will be prompted with several windows allowing you to choose what file types to look for, which locations should be scanned, etc. All you need to do is select the options you're looking for and start the scan. We advise you to enable the "Deep Scan" before starting, otherwise, the application's scanning capabilities will be restricted.

Wait for Recuva to complete the scan. The scanning duration depends on the volume of files (both in quantity and size) that you are scanning (for example, several hundred gigabytes could take over an hour to scan). Therefore, be patient during the scanning process. We also advise against modifying or deleting existing files, since this might interfere with the scan. If you add additional data (for example, downloading files/content) while scanning, this will prolong the process:

Step 2: Recover data.

Once the process is complete, select the folders/files you wish to restore and simply click "Recover". Note that some free space on your storage drive is necessary to restore data:

Create data backups:

Proper file management and creating backups is essential for data security. Therefore, always be very careful and think ahead.

Partition management: We recommend that you store your data in multiple partitions and avoid storing important files within the partition that contains the entire operating system. If you fall into a situation whereby you cannot boot the system and are forced to format the disk on which the operating system is installed (in most cases, this is where malware infections hide), you will lose all data stored within that drive. This is the advantage of having multiple partitions: if you have the entire storage device assigned to a single partition, you will be forced to delete everything, however, creating multiple partitions and allocating the data properly allows you to prevent such problems. You can easily format a single partition without affecting the others - therefore, one will be cleaned and the others will remain untouched, and your data will be saved. Managing partitions is quite simple and you can find all the necessary information on Microsoft's documentation web page.

Data backups: One of the most reliable backup methods is to use an external storage device and keep it unplugged. Copy your data to an external hard drive, flash (thumb) drive, SSD, HDD, or any other storage device, unplug it and store it in a dry place away from the sun and extreme temperatures. This method is, however, quite inefficient, since data backups and updates need to be made regularly. You can also use a cloud service or remote server. Here, an internet connection is required and there is always the chance of a security breach, although it's a really rare occasion.

We recommend using Microsoft OneDrive for backing up your files. OneDrive lets you store your personal files and data in the cloud, sync files across computers and mobile devices, allowing you to access and edit your files from all of your Windows devices. OneDrive lets you save, share and preview files, access download history, move, delete, and rename files, as well as create new folders, and much more.

You can back up your most important folders and files on your PC (your Desktop, Documents, and Pictures folders). Some of OneDrive’s more notable features include file versioning, which keeps older versions of files for up to 30 days. OneDrive features a recycling bin in which all of your deleted files are stored for a limited time. Deleted files are not counted as part of the user’s allocation.

The service is built using HTML5 technologies and allows you to upload files up to 300 MB via drag and drop into the web browser or up to 10 GB via the OneDrive desktop application. With OneDrive, you can download entire folders as a single ZIP file with up to 10,000 files, although it can’t exceed 15 GB per single download.

OneDrive comes with 5 GB of free storage out of the box, with an additional 100 GB, 1 TB, and 6 TB storage options available for a subscription-based fee. You can get one of these storage plans by either purchasing additional storage separately or with Office 365 subscription.

Creating a data backup:

The backup process is the same for all file types and folders. Here’s how you can back up your files using Microsoft OneDrive

Step 1: Choose the files/folders you want to backup.

Click the OneDrive cloud icon to open the OneDrive menu. While in this menu, you can customize your file backup settings.

Click Help & Settings and then select Settings from the drop-down menu.

Go to the Backup tab and click Manage backup.

In this menu, you can choose to backup the Desktop and all of the files on it, and Documents and Pictures folders, again, with all of the files in them. Click Start backup.

Now, when you add a file or folder in the Desktop and Documents and Pictures folders, they will be automatically backed up on OneDrive.

To add folders and files, not in the locations shown above, you have to add them manually.

Open File Explorer and navigate to the location of the folder/file you want to backup. Select the item, right-click it, and click Copy.

Then, navigate to OneDrive, right-click anywhere in the window and click Paste. Alternatively, you can just drag and drop a file into OneDrive. OneDrive will automatically create a backup of the folder/file.

All of the files added to the OneDrive folder are backed up in the cloud automatically. The green circle with the checkmark in it indicates that the file is available both locally and on OneDrive and that the file version is the same on both. The blue cloud icon indicates that the file has not been synced and is available only on OneDrive. The sync icon indicates that the file is currently syncing.

To access files only located on OneDrive online, go to the Help & Settings drop-down menu and select View online.

Step 2: Restore corrupted files.

OneDrive makes sure that the files stay in sync, so the version of the file on the computer is the same version on the cloud. However, if ransomware has encrypted your files, you can take advantage of OneDrive’s Version history feature that will allow you to restore the file versions prior to encryption.

Microsoft 365 has a ransomware detection feature that notifies you when your OneDrive files have been attacked and guide you through the process of restoring your files. It must be noted, however, that if you don’t have a paid Microsoft 365 subscription, you only get one detection and file recovery for free.

If your OneDrive files get deleted, corrupted, or infected by malware, you can restore your entire OneDrive to a previous state. Here’s how you can restore your entire OneDrive:

1. If you're signed in with a personal account, click the Settings cog at the top of the page. Then, click Options and select Restore your OneDrive.

If you're signed in with a work or school account,  click the Settings cog at the top of the page. Then, click Restore your OneDrive.

2. On the Restore your OneDrive page, select a date from the drop-down list. Note that if you're restoring your files after automatic ransomware detection, a restore date will be selected for you.

3. After configuring all of the file restoration options, click Restore to undo all the activities you selected.

The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups.

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