15 Dec
2015
15 Dec
'15
8:49 a.m.
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(a)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/i…
*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_*.
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++++++==============================================================================================================+++++++======-
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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