CyberStack

MITRE ATT&CK / Techniques / T1133

External Remote Services

ID
T1133
Tactics
TA0001 Initial Access, TA0003 Persistence
Platforms
Containers, Linux, macOS, Windows
Data sources
User Account Authentication, Application Log Content, Network Connection Creation, Logon Session Metadata, Network Traffic Flow
Source
attack.mitre.org
MITRE last modified
12 May 2026

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.[2]

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.[3] 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.[4][5]

Adversaries may also establish persistence on network by configuring a Tor hidden service on a compromised system. Adversaries may utilize the tool ShadowLink to facilitate the installation and configuration of the Tor hidden service. Tor hidden service is then accessible via the Tor network because ShadowLink sets up a .onion address on the compromised system. ShadowLink may be used to forward any inbound connections to RDP, allowing the adversaries to have remote access.[6] Adversaries may get ShadowLink to persist on a system by masquerading it as an MS Defender application.[7]

Detection

Mitigations (5)

M1021 Restrict Web-Based Content

Restrict all traffic to and from public Tor nodes. [1]

M1030 Network Segmentation

Deny direct remote access to internal systems through the use of network proxies, gateways, and firewalls.

M1032 Multi-factor Authentication

Use strong two-factor or multi-factor authentication for remote service accounts to mitigate an adversary's ability to leverage stolen credentials, but be aware of Multi-Factor Authentication Interception techniques for some two-factor authentication implementations.

M1035 Limit Access to Resource Over Network

Limit access to remote services through centrally managed concentrators such as VPNs and other managed remote access systems.

M1042 Disable or Remove Feature or Program

Disable or block remotely available services that may be unnecessary.

Groups (28)

Software (5)

References

  1. Defending Against Malicious Cyber Activity Originating from Tor
  2. MacOS VNC software for Remote Desktop
  3. Volexity Virtual Private Keylogging
  4. Trend Micro Exposed Docker Server
  5. Unit 42 Hildegard Malware
  6. The BadPilot campaign
  7. Russian threat actors dig in, prepare to seize on war fatigue