Beware CryptoLocker

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We have seen a rise in CryptoLocker virus attacks; these attacks can cripple the data files on your computer and on your computer network.

CryptoLocker is a destructive, ransomware virus; once downloaded, it locates and encrypts data files, which renders them inaccessible.  CryptoLocker does not announce its presence until all data files (Microsoft Office files, PDF files, etc.) are encrypted; it then asks for payment (ransom) to unencrypt these files.  (This type of ransomware is called “cryptoviral extortion”.)

The usual virus-delivery method is via email; the email looks legitimate and includes an attachment.  Once the attachment is clicked, the virus starts and then continues until all data files are encrypted or until the computer is powered-down.

You will not be able to unencrypt these files.  There is no cure.  There is no fix.

If the infected computer is connected to a computer network, data files on other computers and/or on the server(s) may also be encrypted and made inoperable.

Although payment is demanded to unencrypt the files, it should not be sent since any type of response to these criminals could open your computer network to future attacks.  The only recommended recovery method is to restore the encrypted data files from the latest backup.

Please visit http://www.bleepingcomputer.com/virus-removal/cryptolocker-ransomware-information for more information on CryptoLocker.

Mike Morel, Engineer at Bryley Systems, suggests adopting these practices to reduce the risk of activating the CryptoLocker virus on your computer:

  • Do not open attachments within emails from sources that look legitimate, but are unexpected.
  • If you are expecting an attachment from someone, save the attachment first (without opening it) and then scan the attachment with your malware and anti-virus scanners before opening it.
  • Backup all data files regularly.

If you discover this virus, please immediately power-down the offending computer; if it is connected to a computer server, shutdown the computer network.  Then, call Bryley Systems at 978.562.6077 and select option one for technical support.

For additional information, see our lead article “Cybercrime targets smaller organizations” from the September 2012 edition of Bryley Tips and Information at

https://www.bryley.com/news/newsletter/bryley-tips-and-information-september-2012/.

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Tips on email attachments

Most folk send attachments with their emails; it is a quick, easy way to share a file with the email recipient.  However, attachments can have a negative impact on your computer-network infrastructure:

  • Emails saved with attachments consume storage.
  • Large attachments slow performance and may be rejected by the provider.
  • Attachments copied to a distribution list (a group of email users) are copied multiple times, once for each user, which can impact network bandwidth.

In addition, emails received with attachments should be treated cautiously, since attachments may become sources of infection.  Basic suggestions when receiving:

  • Do not open if the sender is unknown or suspect.
  • Limit total attachments to under one Gb; zip files greater than one Gb.