Further to our earlier story regarding Synology NAS users having their files encrypted through a ransomware exploit known as “SynoLocker”, the company today admitted that they were unable to offer decryption support for affected users.

An update from Synology today reinforced the fact that the security exploit in the company’s DiskStation Manager software was patched in December 2013. While the company recommends users update their NAS devices to the latest version of DSM (or one of a number of earlier releases apparently unaffected by the issue) there is little comfort for users whose files have already been taken hostage by the exploit.

Synology said today, “For users who have encountered the above symptoms, please shutdown the system immediately to avoid more files from being encrypted and contact our technical support… However, Synology is unable to decrypt files that have already been encrypted.”

Over the last few months, Synology has released a number of updates to patch security holes in the DiskStation Master software. In February 2014, the company announced a patch for a serious exploit that could allow users to gain unauthorised access to data remotely. Then, just last week, another update was released to prevent denial of service attacks on Synology NAS devices.

Whether Synology’s software is less secure than other NAS vendors is unknown, however. It may be that the company is simply the first NAS vendor to be attacked with such an exploit at scale. Certainly, you’d like to think that all of the NAS manufacturers are reviewing their code urgently in the light of this development.

If you have concerns about the vulnerability of the data on your NAS, then you may wish to switch off remote access to your device for the time being – or at the very least, ensure you have the latest version of your NAS device’s operating system on board.

Here’s the latest update from Synology in full:

 

Synology has confirmed the ransomware affects Synology NAS servers running older versions of DiskStation Manager, by exploiting a vulnerability that was fixed in December, 2013, at which time Synology released patched software and notified users to update via various channels. Affected users may encounter the following symptoms:

  • When attempting to log in to DSM, a screen appears informing users that data has been encrypted and a fee is required to unlock data.
  • Abnormally high CPU usage or a running process called “synosync” (which can be checked at Main Menu Resource Monitor).
  • DSM 4.3-3810 or earlier; DSM 4.2-3236 or earlier; DSM 4.1-2851 or earlier; DSM 4.0-2257 or earlier is installed, but the system says no updates are available at Control Panel >DSM Update.

For users who have encountered the above symptoms, please shutdown the system immediately to avoid more files from being encrypted and contact our technical support here:https://myds.synology.com/support/support_form.php. However, Synology is unable to decrypt files that have already been encrypted. For other users who have not encountered the above symptoms, Synology strongly recommend downloading and installing DSM 5.0, or any  version below:

  • DSM 4.3-3827 or later
  • DSM 4.2-3243 or later
  • DSM 4.0-2259 or later
  • DSM 3.x or earlier is not affected

Users can manually download the latest version from our Download Center and install it at Control Panel DSM Update Manual DSM Update.

Synology sincerely apologises for any problems or inconvenience this issue has caused our users. As cybercrime proliferates and increasingly sophisticated malware evolves, Synology continues to devote resources to mitigate threats and is dedicated to providing users with reliable solutions. If users notice their DiskStation behaving suspiciously even after being upgraded to the latest DSM version, please contact security@synology.com

For the technical details on how the SynoLocker exploit works, check out this article from F-Secure.