ExtraHop named a Leader in the 2025 Forrester Wave™: Network Analysis And Visibility Solutions

Search
  • Platformchevron right
  • Solutionschevron right
  • Modern NDRchevron right
  • Resourceschevron right
  • Companychevron right

DETECTION OVERVIEW

Unusual Protocol Connection from a High Value Device

Risk Factors

Certain high value devices might only require a specific set of protocols for routine tasks. A high value device that initiates unusual protocol connections might indicate command-and-control (C&C) communication with an attacker-controlled server. High value devices are frequent targets for advanced persistent threat (APT) groups. Depending on which high value device was compromised, attackers might gain direct access to devices on a network or sensitive data.

The system might change the risk score for this detection.

Category

Command-and-Control
Detection diagram
Next in Command-and-Control: Unusual Protocol for Enterprise Software

Attack Background

An adversary can choose from many attack techniques to install malware on a high value device, from performing supply-chain attacks to exploiting unknown (zero-day) vulnerabilities. Malware then initiates an outbound connection to an attacker-controlled server outside the network. The malware can send data to the attacker or receive malicious commands over a C&C connection.

The ExtraHop system detects C&C connections from high value devices by observing historical behavior. High value devices are designated by users or by the ExtraHop system, which automatically identifies high value devices based on their influence on network services. High value devices are often specialized to perform essential services and might be associated with specific behaviors. Malware might cause a compromised device to exhibit unusual behavior, such as outbound connections to new external endpoints over new protocols.

The following diagram shows one example scenario where malware installed on a high value device initiates an outbound connection to an attacker.

Mitigation Options

Block unnecessary protocols at the network perimeter
Quarantine the device while checking for indicators of compromise, such as the presence of malware
Implement network segmentation and the principle of least privilege on accounts to minimize the damage caused by a compromised device

MITRE ATT&CK ID

Associated content

Announcing The Forrester Wave™: Network Analysis And Visibility Solutions, Q4 2025

Network analysis and visibility solutions remain underrepresented in enterprises. Find out why in this preview of a new Wave report.

Report

ExtraHop® Named a Leader in First-Ever Gartner® Magic Quadrant™ for Network Detection and Response — ExtraHop

ExtraHop® Named a Leader in First-Ever Gartner® Magic Quadrant™ for Network Detection and Response

News

Detections

Visit this resource for more information.

Docs

The 2025 ExtraHop Global Threat Landscape Report: The Alarming Reality of Threat Actor Dwell Time and Deeper Network Access — ExtraHop

This analysis exposes the critical link between an organization's lack of internal visibility and the escalating cost of compromise, demanding an urgent re-evaluation of how core business assets are protected.

Blog

ExtraHop RevealX MITRE ATT&CK Coverage 2024 — ExtraHop

Learn why you need to be wary of the claims certain network detection and response providers make about their coverage against the MITRE ATT&CK framework.

Blog

MITRE ATT&CK - Network Detection & Response with RevealX — ExtraHop

Learn how NDR from RevealX helps security teams detect and investigate more adversary TTPs in the MITRE ATT&CK framework than rule-based tools.

External
Periodic Table of Use Cases

What else can RevealX do for you?