Thanks for the infos.

I summarise in this case:

• 20 000+ files to be recovered with this kind of tool would mean a very heavy work load and delay, so fresh backups are still far away the best solution (if available).
• If the attack would have not been stopped very quickly (would have started a Friday evening, as example), this tool couldn't possibly be used to restore the 200+ million files.
• The lost of the exact file name, path and user rights means, for such a professional installation, the lost of the data, as the exact file names and path are mandatory for several critical business applications that are to be used all the time by the 70 staff.
• As the restored file integrity is not guaranteed, the situation of the victim is still not comfortable (how to check each file data correctness in such a large case ?).
• This tool would require the interruption of the share availability during the data restoration process. Thanks the backup and the restoration by a small bash script, the staff was still able to work during the restore period. So off-line regular full backups are definitely the best solution.
  

This tool is certainly useful for restoring some important files (and good to know), but I don't see it as a solution against those ransom-wares, especially in large scale professional installations...

Files in the "recycle-bin" are not actually removed yet, and chances
are, if the ransomware is any good, it will take care to remove the
recycle bin.

On the infected (so Windows) computer, I have no idea how it behaved, as the system has been switched off, promptly fully formatted and re-installed. But as this not the first version of this ransom-ware, I'm pretty sure it takes care to override the original file, as much as it could.

On the Samba server, a VFS stackable Samba module was used on some (selected) shares, and there, the original files have been found in the recycle directory after the attack. Unfortunately, those files were also encrypted !

Le 15.12.2015 09:49, Alain Knaff a écrit :

On 15/12/15 09:40, Brent Frère wrote:

Thanks for the trick.

In a corporate case, the server is usually heavily working, and so
re-allocating the hard-disk space frequently.

It also depends on how full it is. It is my understanding, that on a
less full disk, it may still take a while until the space is
re-allocated (but obviously this varies depending on which filesystem is
used...)

In this case, there are about 200 millions files on-line, 70 users and
several tens of TB involved.
The attack managed to encrypt more than 20 000 files before it was
stopped (half an hour or so).
Some of the files were founded back in trashes, but not all (far from
that) as such a "recycle bin" feature was not enabled on all the shares.
I don't know the default behaviour of Windows servers, but the server is
here a Samba on Linux, due to the need of compatibility, stability,
availability and scalability.
The file system is probably not compatible with your tool.

Errrm.... "his" tool is "photorec", a filesystem-independant tool that
looks for signatures of various file types, and from there just works on
the assumption that most files are stored contiguously (which is
generally true today, if the disk is not too filled up, and especially
on Linux filesystems). As such, the tool is totally file-system
independant, and recovers a large amount of files. The only disadvantage
is that file *names* are lost (for these, it would need to be filesystem
aware)

Is there a "recycle-bin" feature activated by default on Windows servers ?

Files in the "recycle-bin" are not actually removed yet, and chances
are, if the ransomware is any good, it will take care to remove the
recycle bin.

... and the next version will surely rewrite files in place, rather than
doing a copy+delete :-)

How to restore thousands of files from this situation ? Does you tool
automatise this ? Are the file names, paths and the access rights
correctly restored in all the cases ?

With photorec, no. It just gives the files generic names, only the
extension is meaningful. Same for permissions: these will be generic as
well. So, after photorec, there's still a lot of work to do to sift
through all the recovered files, to find those that are meaningful.

However, in some cases, there may be metadata in the files themselves
(such as dates in EXIF headers of photos), which may help with that task.

It's just a question, for me to know.

At least with a full daily backup, we managed to restore the 20 000+
files in half an hour, *thanks a small minute-maid bash script*.

Thanks for your info anyway.

Regards,

Alain

Le 11.12.2015 13:31, Micha Lippert a écrit :

Hello,

someone in my family managed to get infected by such a ransomware.
The files are encrypted, and the originals are deleted. These deleted
files may be recovered with a bit of luck.
I just used my favourite forensic tool (photorec) and managed to
salvage a large percentage of his files.

So if you encounter this problem: Don't panic. Shut down the machine.
Google about forensic tools.
But granted, backups are a better alternative, as long as they are
offline during the attack...

best regards,
Micha



2015-12-04 18:17 GMT+01:00 Brent Frère <Brent.Frere@abilit.eu
<mailto:Brent.Frere@abilit.eu>>:

    Vous avez peut-être lu récemment des articles dans la presse
    luxembourgeoise concernant les "rançonwares".
   
http://www.guichet.public.lu/citoyens/fr/actualites/2015/02/09-ransomware/index.html

    *Il y a actuellement une vague des ce type d'attaques sur le
    Luxembourg.*

    Ces attaques sont *très efficaces et très sérieuses*. Elles
    s'introduisent via des e-mails contenant des pièces-jointes
    contenant le logiciel malveillant, écrit en Java, souvent sous
    forme d'archive ZIP.
    Elles traverses tout type de firewall et la plupart des systèmes
    de filtrage des e-mails (antispam/antivirus).
    Il suffit que l'utilisateur ouvre ce logiciel (clique sur la pièce
    jointe) pour que _TOUS LES FICHIERS ACCESSIBLES_ par cet
    utilisateur, même sur les serveurs de l'entreprise, se retrouvent
    cryptés et donc inutilisables.
    La seule solution, ensuite, est de payer la rançon réclamée par
    les voleurs (donc leur donner votre numéro de carte de crédit et
    le cryptogramme... ???) ou de récupérer vos fichiers dans un
    backup, à condition qu'il soit à jour.

    Bien sûr, ces attaques ne fonctionnent pas sur le système le plus
    utilisé dans le monde et sur Internet (Linux, sous ses diverses
    formes et noms, dont Android), mais profitent des faiblesses
    (encore et toujours) des logiciels propriétaires bien connus:
    Windows (toutes versions), la version Java de Oracle, Outlook, etc...

    Si vous êtes (encore) utilisateurs de ces logiciels totalement
    perméables par nature (probablement par choix de leurs éditeurs si
    ce n'est du fait de leur incompétence), _veillez d'urgence_ à ce
    que vos backups soient à jour et inaccessibles par les ordinateurs
    tournant ce genre de système d'exploitation.

    De nombreuses attaches effectives et réussies ont eu lieu, y
    compris auprès de certains de nos clients. Si vous ne prenez pas
    les précautions élémentaires d'urgence, vous n'aurez plus, en
    quelques heures, que le genre de message suivant en remplacement
    de *_toutes les données de votre entreprise_*.

     
++++++==============================================================================================================+++++++======-

    What happened to your files ?
    All of your files were protected by a strong encryption with
RSA-2048.
    More information about the encryption keys using RSA-2048 can be
found
    here:http://en.wikipedia.org/wiki/RSA_(cryptosystem)
    <http://en.wikipedia.org/wiki/RSA_%28cryptosystem%29>

    What does this mean ?
    This means that the structure and data within your files have been
    irrevocably changed, you will not be able to work with them, read
them
    or see them,
    it is the same thing as losing them forever, but with our help,
you can
    restore them.

    How did this happen ?
    Especially for you, on our server was generated the secret key pair
    RSA-2048 - public and private.
    All your files were encrypted with the public key, which has been
    transferred to your computer via the Internet.
   
++++++==============================================================================================================+++++++======

    Decrypting of your files is only possible with the help of the
private
    key and decrypt program, which is on our secret server.

    What do I do ?
    So, there are two ways you can choose: wait for a miracle and get
your
    price doubled, or start obtaining BTC NOW, and restore your data
easy way.
    If You have really valuable data, you better not waste your time,
    because there is no other way to get your files, except make a
payment.

    For more specific instructions, please visit your personal home
page,
    there are a few different addresses pointing to your page below:
    1.http://alcov44uvcwkrend.paybtc798.com/96EF1674B48EED9A
    2.http://alcov44uvcwkrend.btcpay435.com/96EF1674B48EED9A
    3.https://alcov44uvcwkrend.onion.to/96EF1674B48EED9A
          If for some reasons the addresses are not available, follow
these steps:
    1. Download and install tor-browser:
    http://www.torproject.org/projects/torbrowser.html.en
    2. After a successful installation, run the browser and wait for
    initialization.
    3. Type in the address bar: alcov44uvcwkrend.onion/96EF1674B48EED9A
    4. Follow the instructions on the site.

    IMPORTANT INFORMATION:
    Your personal pages:
    http://alcov44uvcwkrend.paybtc798.com/96EF1674B48EED9A
    http://alcov44uvcwkrend.btcpay435.com/96EF1674B48EED9A
    https://alcov44uvcwkrend.onion.to/96EF1674B48EED9A       Your
personal page (using TOR-Browser):
    alcov44uvcwkrend.onion/96EF1674B48EED9A
    Your personal identification number (if you open the site (or
    TOR-Browser's) directly): 96EF1674B48EED9A
   
++++++==============================================================================================================+++++++======

    Si vous pensez que vos backups peuvent ne pas être parfaitement à
    jour, veuillez nous contacter _d'urgence_.
    Cette attaque fonctionne très très bien et il n'y a pas de moyen
    de récupérer vos données une fois l'attaque en cours.

    Vous avez été averti...

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