As a computer and security specialist, I see a lot of viruses and malware. But more often than not, the removal of the malicious code from a computer system repairs the issue. A new ransomware application has popped up however that raises some real concern, because it in fact destroys your data in a seemingly unrecoverable way, and removal of the malware simply leaves your files in an inaccessible state with no chance at recovery.
What is it?
CryptoLocker is a new and cunning piece of ransomware discovered last month. Its spread is increasing, and we’re starting to see infections in a growing number of unrelated networks here in Ontario.
CryptoLocker needs to be taken very seriously, because it can result in the total and irreversible destruction of all your personal and company files.
What Does It Do?
CryptoLocker places itself on a Windows machine, easily circumventing even the best antivirus protection, at least at the time I write this. It appears to get in by way of an infected web site or possibly an infected email attachment masquerading as a seemingly legitimate file such as tracking data for a courier shipment, a money transfer or other fake electronic money transaction.
Once infected, the malware crawls through all mounted volumes (hard drives, network shares, USB drives, camera cards, etc.) for a variety of filetypes, mostly documents, spreadsheets, PDF files, pictures, etc., and encrypts them. This means the files on your own hard drive, your network mapped drives, and even cloud-based drives are encrypted (destroyed, made unreadable). Because the decryption key is not known, recovery is not an option.
Once the encryption process is complete, the software then launches an application window displaying a message that all your files have been locked, and you must pay the ransom ($300 is common right now) in order to recover your files.
Current, up to date antivirus tools detect the trojan and remove the malware software after the damage is done to your files. This results in the permanent inability to recover your files.
Perhaps the best way to explain the devastating effects of CryptoLocker is with a couple of fictitious scenarios:
A small business has a two-drive RAID mirror unit in their server as a form of backup. They have one extra drive, and the system features a removable tray caddy. This allows them to swap one of the hard drives each day and take it off-site.
One staff member was working on the system that morning and received an alert that their data had been encrypted after they opened a suspicious email attachment. They closed the alert and left the room.
The manager arrived an hour later and removed the second hard drive from the array, replacing it with the one they brought from home: their morning routine. The drive rebuilt based on the first drive, which now contains only encrypted data, and now all three drives are corrupt. All files are lost, including their backup.
A business office with a shared folder on the server uses that share for all their company data. Every workstation in the office has the share mounted to their Q: drive. This contains Excel spreadsheets, Word documents, PDF catalogues, product pictures and more.
The company feels this is a good way to manage their internal files since it gives all staff access to the files, is a RAID 1 mirrored drive (so if a hard drive crashes, they lose nothing) and it allows them to backup one single folder to the external backup drive on a nightly basis, resulting in the backup of all critical files.
One staff member is wrapping up their shift and quickly uses their computer to search for discounted tickets for an upcoming concert. They do a search in Google and start clicking on all the results to see which one offers the best deal, unconcerned about the fact that they do not recognize even one of the web sites as a reputable ticket source. Unbeknownst to the user, one of those sites is infected with CryptoLocker, which installs itself in the background while they search.
CryptoLocker silently goes through C: and corrupts every document, every spreadsheet, practically every personally-created file. It then finds the Q: drive and gets to work doing the same: corrupting all user files on the network share.
The following morning the user returns to work and finds an alert on their screen saying all files have been encrypted, and they immediately recognize it as being a virus of sorts. They run their virus scanner and it removes the infection without any problem. They go about their day.
All the while, other users on the network start to complain that they can’t access their Q: drive. IT has a look and finds that all files are corrupt and unreadable. They look at the backup drive connected to the server, and it too has been corrupted due to the previous night’s backup. All files are lost, including their backup.
What Can You Do?
If you have already been infected with CryptoLocker and do not have an unaffected backup, unfortunately there is nothing that can be done. It is not recommended that you pay the ransom, nor is there any guarantee that the hacker responsible will actually unlock your files if you do pay (some users have reported having paid the ransom and yet never got their files back).
So it all comes down to preventative measures: protecting yourself from this malware before you get infected.
Backup, backup, backup
I’m not just saying it three times for emphasis. I really mean it: you should have more than one backup solution in place.
Realistically the only true protection against the effects of CryptoLocker and similar viruses is to have a multi-tier backup system protecting the integrity of your files at all times.
Since the files on your drives and network are basically destroyed by CryptoLocker—possibly including your backup—the easiest, safest, and most assured way to recover from an infection should it occur, is by having a detached, unaffected copy of your files.
An off-site backup solution is likely the best option. It means your files are safely stored elsewhere, and if done right, they are stored incrementally. This means if you get an infection and CryptoLocker destroys all your files, and then your backup runs, your good backup does not get overwritten, as would be the case with both scenarios listed above. With an incremental backup, you can in fact restore from days gone by—from before the infection took place.
There are many off-site backup services out there, and I don’t want this to seem like a sales pitch—I genuinely just want you to be safe—so feel free to shop around. But all I ask is that you please include Positive E Solutions in your list of companies to check out. They have a very good, fully encrypted off-site backup service with hosting entirely in Canada. It can be used in conjunction with your existing backup infrastructure to leverage its effectiveness and further protect your critical data. It’s very affordable for either business or home use, and I can even let you try it for free for 30 days to see if it meets your needs. http://positiveesolutions.com/try-now.php
Enable Volume Shadow Copy
Windows 7/Server 2008/Vista/Server 2003 have a feature called Volume Shadow Copy. It’s not to be mistaken for a backup, but it is a helpful tool in recovering from this type of infection: essentially a duplicate of the files found on volumes you specified to have shadowed. In the event of a CryptoLocker attack, your files are destroyed from their original locations, but the Volume Shadow Copy is untouched by the current incarnation of CryptoLocker, due likely to the special permissions required to write to the Volume Shadow Copy itself. Therefore, following the removal of CryptoLocker, you can right-click on the affected files or folders and revert to an earlier snapshot.
There are a ton of tutorials out there which teach how to enable Volume Shadow Copy, so I’ll avoid making this one of them. Activating Volume Shadow Copy helps reduce recovery time should a CryptoLocker infection take place.
It is a good idea, I think, to enable Volume Shadow Copy at the server level, directly on the volume containing your network share folders. In Scenario 2 above, this would be the RAID 1 which contains the contents of their Q: drives. That way, the shadow copy could be used to quickly restore to a previous set of files. If that doesn’t work, the backup can be used.
Update Flash and Java, But Disable Java in your Browser
I had a discussion with malware expert Adam Kujawa yesterday about CryptoLocker. He mentioned that Java and Flash are two of the main ways this virus is able to enter a Windows system. An unsuspecting user might conduct a search for something in Google, and click on a few links, and one of those web sites could be infected with the distribution mechanism to install CryptoLocker on your system. The recommendation is to disable Java from your web browser (only enabling it when needed), and absolutely keep both Java and Flash up to date.
Keep Your Antivirus / Anti-Malware Up To Date
The instant they release protection for this, you want to receive it. This is not a replacement for my backup suggestion above, but will save you some headaches.
Be Careful What You Click
We have received reports that CryptoLocker infections originated both from infected web sites and emails. It’s tough to ensure entire staff are cautious, but it’s still important for me to mention. If something appears suspect, don’t click it. If you receive an email you’re not expecting, don’t open it. If “your bank” sends you transaction details for a transaction you don’t remember making, don’t click the links. Just be careful what you click. These infections are able to circumvent the antivirus.
Mac and Linux Users
While CryptoLocker does not directly infect Mac or Linux machines at this time, these systems may have network-accessible file shares open to the network or a virtual machine. Therefore if a Windows computer on the network or a Windows virtual machine becomes infected with CryptoLocker, it is possible to lose the files hosted on your Mac or Linux computer (or NAS device).
Cloud Users Beware
CryptoLocker will crawl through and destroy personal files on cloud-based mapped drives such as Google Drive, PogoPlug or DropBox.
Thanks for reading, and stay safe!