The Department of Homeland Security (DHS) National Cybersecurity and Communications Integration Center (NCCIC) and the Federal Bureau of Investigation (FBI) are issuing this activity alert to inform computer network defenders about SamSam ransomware, also known as MSIL/Samas.A.
The SamSam actors targeted multiple industries, including some within critical infrastructure. Victims were located predominately in the United States, but also internationally. Network-wide infections against organizations are far more likely to garner large ransom payments than infections of individual systems. Organizations that provide essential functions have a critical need to resume operations quickly and are more likely to pay larger ransoms.
You may review the entire DHS/FBI alert here.
This threat is primarily targeting Remote Desktop Protocol (RDP) ports and systems. The primary recommendation is close these ports or layer in two-factor authentication, at a minimum. Onepath, the firm I work for, never recommends leaving RDP ports open to the Internet. They should only be accessed from behind a firewall, through a VPN and always secure with two factor authentication.
The following are specific recommendations contained in this alert. I strongly support each of these recommendations. If you are unsure if your company is properly protected, reach out to your IT department or IT partner immediately to assess your vulnerability.
DHS and FBI recommend that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. System owners and administrators should review any configuration changes before implementation to avoid unwanted impacts.
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.
Finally, here is a link to Onepath’s blog post on this matter.