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

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DETECTION OVERVIEW

Spike in Telnet Connections

Risk Factors

While Telnet is an older and vulnerable protocol, it is often enabled by default. Data is sent over the Telnet protocol as plaintext, which increases the risk of exposing passwords to attackers. If an attacker gains access to a poorly-secured Telnet server, they can easily connect to the device and laterally move across the network.

The system might change the risk score for this detection.

Category

Exploitation
Detection diagram
Next in Exploitation: Spring Cloud Function Exploit Attempt - CVE-2022-22963

Attack Background

After an attacker compromises a device on a network, they might start searching for databases, file servers, and other critical assets to compromise. Remote access protocols, such as Telnet, can enable an attacker to laterally move across a network, from one compromised device to the next. First, the attacker sends a connection request over Telnet to one or more devices. If one of these devices has Telnet enabled, the attacker might be able to log in with stolen credentials. Each authenticated Telnet session enables the attacker to remotely access information, helping them get closer to achieving their ultimate attack campaign objective.

Mitigation Options

Disable Telnet unless required

Implement strict access controls to devices that have Telnet enabled

Configure a firewall to block untrusted IP addresses from accessing devices that have Telnet enabled

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.

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

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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.

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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.

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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.

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