New decryption tool for Crysis ransomware

Update (March 2nd, 2017): Decryption tool for Crysis ransomware updated for new version

Today, ESET has released updated version of its free decryptor for victims of Crysis ransomware, adding new variant of the infamous ransomware – .dharma – to its list. The current update of ESET’s decrypting tool now can help victims of six variants of Crysis ransomware family with following extensions: .xtbl, .crysis, .crypt, .lock, .crypted, and .dharma.

If you have been a victim of Crysis ransomware, you can find and download the free ESET Crysis decryptor from our free utilities page. If you need additional information on how to use the tool, please refer to ESET Knowledgebase.

                                                                      

Since it first appeared, ransomware’s profitable business – in short, compromising and encrypting data belonging to companies and users and requesting payment in exchange for the restoration of infected files –has grown rapidly.

One of the threats that has had a significant impact and infected a considerable number of users worldwide was the family detected by ESET solutions as Win32/Filecoder.Crysis. However, and luckily, ESET has developed a free tool to decrypt files and recover the information that might have been compromised.

What is Crysis?

Crysis is a Filecoder-type malicious code whose purpose, as its name suggests, is to encrypt information and request the payment of a ransom in exchange for the return of said information. Crysis uses RSA and AES encryption with long encryption keys, which makes the recovery of processed files almost impossible.

This family of malware gained popularity after TeslaCrypt, another ransomware that also spread widely while it was active (it ceased its operations early this year upon the launch of a tool to revert it).

Top 10 most affected countries by Crysis

Crysis spreads via multiple vectors, ranging from emails to ads in social networks.

The growth in the number of worldwide detections started at the end of May. To date, ESET solutions have detected variants of this malware family in 123 countries, although almost 60% is concentrated in only 10 countries:

Top 10 countries_Crysis

Some characteristics of Crysis

This ransomware is simply an executable file that is not protected by a packer, which can be easily verified in the file header:

2_cabecera_Crysis

Doing a static analysis, we can identify some of the main characteristics. One of the first actions attempted by the ransomware is to create copies of itself in the following directories in order to persist in the system:

  • C:\Users\Victim\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup
  • C:\Windows\System32

The first directory is used by the operating system to execute all the applications within this directory once the user has logged on. It is clear that in this way the threat makes sure it encrypts recently created files.

3_persistencia_crysis

In the second folder, the ransomware prevents the user from noticing its presence by hiding itself in a native folder, essential for Windows.

4_carpeta_donde_se_oculta_crysis

One thing particular about Crysis is that it deletes the backup copies created by “Volume Shadow Copy Service”, a Windows XP built-in application.

In short, the VSS service creates shadow copies of files every time a variation in the system occurs as a consequence of the installation or update of a software. As observed in the screenshot, the threat will execute a series of specific commands to delete the backup, in case there is any.

5_borrado_vss_crysis

Below, we can see the malicious code execution flow, whose first instructions include calls to the functions mentioned before. We can also see that certain offsets contain the strings that will be used to rename the encrypted files and, in addition, a list of file extensions which will show the files searched by the threat to be encrypted.

6_strings_crysis

Then, files containing the steps to follow to recover files shall be created, which will vary depending on the ransomware; however, Crysis will use text files or images to guide the user.

7_mensajes_rescate_crysis

One of the last actions taken by the threat after encrypting the user information is to send information such as the device name and an identifying code, using the HTTP protocol. It is worth mentioning that the sites to where the threat connects are compromised sites, generally servers with some vulnerable version of WordPress.

8_conexiones_http_crysis

A new tool to recover encrypted files

ESET has created a free decryption tool for Crysis ransomware victims in order to help anyone whose data or devices have been affected by the Crysis family. The tool was developed using the master decryption keys recently published.

If you have been a victim of Crysis ransomware, you can find and download the ESET Crysis decryptor from our free utilities page. If you need additional information on how to use the tool, please refer to ESET Knowledgebase.

 

Author , ESET

  • Hello,

    Thank you very much for this.
    It works with {mailrepa.lotos@aol.com}.CrySiS extension.

    • kanlidy

      I have the same problem, which tool use to decrypt?

  • martin rodley

    Anything I can use on .wallet files

    • brijesh tekrawala

      I am having same issue, if any solution then let me know.

  • Jomon Johny

    There is no images on desktop . All my files are encrypted with .wallet extension . Anybody can suggest any right tool for decryption ??

    Thank You

    • brijesh tekrawala

      I am having same issue, please suggest any options

  • Matt

    What about files encrypted id-70019324.[gutentag@india.com].wallet

    • Matthew Micallef

      Hey Matt did you find anything to help with this ?

      Example
      IMG_9922.JPG.id-50C29A34.[breakdown@india.com].wallet

  • mohamed abd elazim abd elkader

    a new type start appear at march 2017
    Help needed :(

  • Matthew Micallef

    Hi did you find anything to help with the .wallet i also got hit and they encrypted all my backup files so would really love something to help decrypt them !

    Example
    IMG_9922.JPG.id-50C29A34.[breakdown@india.com].wallet

    • Santo Montecalvo

      Did you get any help?

      .

      • Rael

        any update guys?

  • smart soft

    gutentag@india.com].wallet help me with decripter still not found one

  • Michel Batista

    matacas@foxmail.com].wallet help me with decripter still not found one

  • Tom Bagley

    Hey a quick question We just got hit with one of the latest variants, leaving files enc
    rypted with .id-FA3B0904.[sm@uwmanage.com].java extension to the files.

    • Christian Pettersson

      Do not pay, you wont get your files back..

  • Just a guy

    same here got encypted by .java extension (decrypthelp@qq.com) they want half a bitcoin

    • Eslam

      did you find solution? i have same, please help
      my files infected with Workup Ransomware

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