There are two types of ransomware in circulation:

Ransomware is a sophisticated piece of malware that blocks the victim’s access to their files.

1. Encrypting ransomware, which incorporates advanced encryption algorithms. It’s designed to block system files and demand payment to provide the victim with the key that can decrypt the blocked content. Examples include CryptoLocker, Locky, CrytpoWall and more.

2. Locker ransomware, which locks the victim out of the operating system, making it impossible to access the desktop and any apps or files. The files are not encrypted in this case, but the attackers still ask for a ransom to unlock the infected computer. Examples include the police-themed ransomware or Winlocker.

3. Another version pertaining to this type is the Master Boot Record (MBR) ransomware. The MBR is the section of a PC’s hard drive which enables the operating system to boot up. When MBR ransomware strikes, the boot process can’t complete as usual, and prompts a ransom note to be displayed on the screen. Examples include Satana and Petya ransomware.

However, the most widespread type of ransomware is crypto-ransomware or encrypting ransomware, which I’ll focus on in this guide. The cyber security community agrees that this is the most prominent and worrisome cyber threat of the moment.

5 Ways to Protect Against the Very Real Threat of Ransomware:

1. Back up your data
The single biggest thing that will defeat ransomware is having a regularly updated backup. If you are attacked with ransomware you may lose that document you started earlier this morning, but if you can restore your system to an earlier snapshot or clean up your machine and restore your other lost documents from backup, you can rest easy. Remember that Cryptolocker will also encrypt files on drives that are mapped. This includes any external drives such as a USB thumb drive, as well as any network or cloud file stores that you have assigned a drive letter. So, what you need is a regular backup regimen, to an external drive or backup service, one that is not assigned a drive letter or is disconnected when it is not doing backup.

The next 3 tips are meant to deal with how Cryptolocker has been behaving – this may not be the case forever, but these tips can help increase your overall security in small ways that help prevent against a number of different common malware techniques.

2. Show hidden file-extensions
One way that Cryptolocker frequently arrives is in a file that is named with the extension “.PDF.EXE”, counting on Window’s default behavior of hiding known file-extensions. If you re-enable the ability to see the full file-extension, it can be easier to spot suspicious files.

3. Filter email with mail gateway
If your firewall has the ability to filter files by extension, you may wish to deny mails sent with “.EXE” files, or to deny mails sent with files that have two file extensions, the last one being executable (“*.*.EXE” files, in filter-speak). If you do legitimately need to exchange executable files within your environment and are denying emails with “.EXE” files, you can do so with ZIP files (password-protected, of course) or via cloud services.

4. Disable files running from AppData/LocalAppData folders
You can create rules within Windows or with Intrusion Prevention Software, to disallow a particular, notable behavior used by Cryptolocker, which is to run its executable from the App Data or Local App Data folders. If (for some reason) you have legitimate software that you know is set to run not from the usual Program Files area but the App Data area, you will need to exclude it from this rule.

5. Disable or limit RDP
The Cryptolocker/Filecoder malware often accesses target machines using Remote Desktop Protocol (RDP), a Windows utility that allows others to access your desktop remotely. If you do not require the use of RDP, you can disable RDP to protect your machine from Filecoder and other RDP exploits.

Should you wish to discuss any concerns you have around Ransomeware issue, please don’t hesitate to call the Aliva team as we are more than happy to discuss your organisations specific requirements.  activate@aliva.com.au

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