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MITRE ATT&CK · T1133

External Remote Services

MITRE · cited in 5 of our lessons

Explanation

What attackers do. Attackers use external-facing remote services, such as VPNs, remote desktop gateways and virtual desktop portals, to get in and keep access, usually with stolen or weak credentials. This serves Initial Access and Persistence.

How to defend. Require MFA on all remote access services, patch VPN and gateway appliances promptly, and limit which accounts may connect. Monitor remote access logs centrally and remove unnecessary internet-facing services. Use device checks so only managed devices can connect, and terminate idle sessions.

Signs to look for. Look for logins from unusual countries or anonymising networks, logins by accounts that do not normally use remote access and simultaneous sessions from different locations. A common gap is remote access appliances whose logs are not sent to the security team.

Open the technique on MITRE ATT&CK
The official text
Adversaries may leverage external-facing remote services to initially access and/or persist within a network. Remote services such as VPNs, Citrix, and other access mechanisms allow users to connect to internal enterprise network resources from external locations. There are often remote service gateways that manage connections and credential authentication for these services. Services such as Windows Remote Management and VNC can also be used externally. Access to Valid Accounts to use the service is often a requirement, which could be obtained through credential pharming or by obtaining the credentials from users after compromising the enterprise network. Access to remote services may be used as a redundant or persistent access mechanism during an operation. Access may also be gained through an exposed service that doesn’t require authentication. In containerized environments, this may include an exposed Docker API, Kubernetes API server, kubelet, or web application such as the Kubernetes dashboard.

© The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation (MITRE ATT&CK®).

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