Unfortunately, ransomware problem is growing every day, although a lot of cases we hear and tens of articles and webinars are published about it. In this post, I try to explain the Protection processes against ransomware. Then, with more posts, I will try to explain every steps deeper.
If you have been exposed to it and your files are encrypted, there is nothing much to do. So, it may be important to read these measures.
- Asset Management: You must know all assets in your organization, especially all assets connecting to internet. Meanwhile, you must know immediately when a new device connected to your network. Additionally, devices using Outlook is also important. A device may be able to Access to internet with restiricted policies but it can get email from outside of the organization. Restriction policies on proxys and firewalls cannot work perfectly, and always have some problems on not categorized or newly websites. So, an asset management device and a NAC solution is very important to manage devices.
- Do not use RDP: Remote Desktop Protocol is a common method for attackers to remotely connect to systems, or move laterally and deploy malware. Protocols like Telnet, SSH, SMB, and RDP should not be open to the internet. You should continuously scan your public IP addresses to check whether there is a protocol like these open to the internet. If you still need to open, pay attention to these;
- Local admin accounts should be kept in safe with a PAM solution
- Change the default RDP port
- Implement IP restriction if possible
- Allow remote connection only with recording systems
- Multifactor authentication should be implemented.
- Network Level Authentication (NLA) can be activated on devices. NLA provides a pre authentication step and also protects the System against brute force attacks.
- Implement security policies via Group Policy, and deny local changes
- Disable administrative and hidden shares on clients:
- Block some file types for incoming emails: Block emails including executive files. IF there are some file types that you cannot block because of the business, you should you some measures like sandbox for incoming emails.
- Backup and regularly backup tests: If you lose your all sensitive data, it is very important to have usable backups. For this, firstly, you should separate and isolate your backup network from all others. So, in a situation of compromise, backup networks will be safe. If you lose your backup data too with all data, there is no any other way other than pay the ransom.
Separating and isolating the backup network is a good start, but it is not enough. You must regularly test backup data and should be ensure that they are working. If you have an unusable backup data when you need it, it only means you spent hundereds of gigabytes for nothing.
There is no a System protecting %100 against ransomware, so backups are becoming more critical in this situation.
- Patch your systems regularly: Especially, systems that are open to the internet should be patched quickly. For this, you should have test systems for all your critical systems and patch these tests firstly, then take action quickly for the production systems.
- Awareness: %91 of the attacks begins with email. For an attacker, it s very easy to deceive a user rather than trying to find weaknesses and exploit them. Even if you have hundreds of measurements agains cyber attacks, if one of your users accept and click a malicious email, it means you can be exposed.