I've visited here a number of times, and found the forum contributions very useful. Thanks to the admins for what is an extremely informative and useful site. My first (of hopefully, few) postings relates to an issue following an infection on our network by ransomware calling itself CRYPTOSHIELD 2.0 DANGEROUS. While the moniker might sound like self-praise, it seems well-earned.
We managed to limit the damage by disconnecting the file server from the network as soon as we realised the encryption was under way. We also scanned all PCs and servers with MalwareBytes and we found the source and isolated that too. It will have its hard disk formatted and the OS re-imaged before being reconnected.We had a good backup of the files from the previous night, so the amount of work lost wasn't as bad as it might have been.
The big challenge with this one is the encrypted files themselves. The filename is completely changed and doesn't bear any relation to what it was originally, although you can take a guess at it based on file size. Here is a sample: GUHZOF.QO.[R_SP@INDIA.COM].ID[089042D6D7F07054].CRYPTOSHIELD. The big problem with these is that you can't delete them to make room for the restored files. It appears that the ransomware. Windows is convinced that the file doesn't actually exist, no matter what you try to do with it. I ended up creating a new virtual disk and restoring the files to there and recreating the original share name.
I am looking at ways of responding more quickly to such infections, but even if only a handful of files become encrypted, we don't want to be forced to leave the encrypted ones there even after the originals have been restored. Is there a way to delete these files?
I am also looking at some specific anti-ransomware offerings such as Sophos Intercept X and CyberReason's Ransomfree. Do these products have good reputations?
Something else I was considering was some kind of "tripwire" in the form of a file on the root of workstation C: drives that would be looked for by a monitoring program and an alert sent around if that file wasn't there anymore. I basing this on the assumption that the ransomware will hit the local drives before it hits network drives. Has anybody set up anything like this and does it work or is it even practical?