How to Defend Against the Latest SamSam Ransomware Attacks
On December 3, 2018 the Department of Homeland Security (DHS) and FBI issued an alert for SamSam ransomware also known as MSIL/Samas.A. Read the entire notice here: https://www.us-cert.gov/ncas/alerts/AA18-337A
DHS and the FBI recommend the following best practices to strengthen your security posture and mitigate risk:
- Audit your network for systems that use RDP for remote communication. Disable the service if unneeded or install available patches. Users may need to work with their technology venders to confirm that patches will not affect system processes.
- Verify that all cloud-based virtual machine instances with public IPs have no open RDP ports, especially port 3389, unless there is a valid business reason to keep open RDP ports. Place any system with an open RDP port behind a firewall and require users to use a virtual private network (VPN) to access that system.
- Enable strong passwords and account lockout policies to defend against brute force attacks.
- Where possible, apply two-factor authentication.
- Regularly apply system and software updates.
- Maintain a good back-up strategy.
- Enable logging and ensure that logging mechanisms capture RDP logins. Keep logs for a minimum of 90 days and review them regularly to detect intrusion attempts.
- When creating cloud-based virtual machines, adhere to the cloud provider’s best practices for remote access.
- Ensure that third parties that require RDP access follow internal policies on remote access.
- Minimize network exposure for all control system devices. Where possible, disable RDP on critical devices.
- Regulate and limit external-to-internal RDP connections. When external access to internal resources is required, use secure methods such as VPNs. Of course, VPNs are only as secure as the connected devices.
- Restrict users’ ability (permissions) to install and run unwanted software applications.
- Scan for and remove suspicious email attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
- Disable file and printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
If you have further questions or concerns, please contact Aspire.