How to Know If a Threat Actor Has Accessed Your Server
type: NewsArticle
description: This article explains that every internet-connected server is a target for unauthorized access, and it provides a guide for detecting a compromise. It details common indicators of a breach, such as brute-force login attempts, creation of backdoor accounts, unexpected processes, and data exfiltration patterns. The guide also offers specific commands for examining system logs on both Linux and Windows servers to identify suspicious activity.
date published: 2026-05-23T20:42:01+00:00
date modified: 2026-05-23T21:03:06+00:00
language: en
is accessible for free: true
article body: A practical detection, investigation, and response guide for DevOps engineers, backend developers, security engineers, and startup CTOs. Sobering reality:IBM's 2023 Cost of a Data Breach Report found that the average breach goesundetected for 204 days— nearly 7 months. By the time most teams notice something is wrong, the attacker has already been living in their infrastructure long enough to map every service, exfiltrate sensitive data, and install multiple persistence mechanisms. The detection gap, not the initial intrusion, is what turns an incident into a catastrophe.This guide closes that gap. ## Table of Contents [Introduction](#1-introduction)[Common Signs a Threat Actor Accessed a Server](#2-common-signs-a-threat-actor-accessed-a-server)[Where to Check — Logs & Evidence Sources](#3-where-to-check--logs--evidence-sources)[Network-Based Detection](#4-network-based-detection)[Step-by-Step Investigation Playbook](#5-step-by-step-investigation-playbook)[Useful Commands & Tools](#6-useful-commands--tools)[MITRE ATT&CK Technique Mapping](#7-mitre-attck-technique-mapping)[Indicators of Compromise (IoC) Checklist](#8-indicators-of-compromise-ioc-checklist)[Immediate Response Actions](#9-immediate-response-actions)[Legal, Compliance & Regulatory Obligations](#10-legal-compliance--regulatory-obligations)[Prevention Best Practices](#11-prevention-best-practices)[Windows Server Incident Response](#12-windows-server-incident-response)[Real-World Example](#13-real-world-example-detecting-a-compromised-linux-server)[Conclusion — The DICRP Framework](#14-conclusion--the-dicrp-framework)[Quick Reference](#15-quick-reference) ## 1. Introduction Every server connected to the internet is a target. It is not a question of *if* someone will attempt to access it without authorisation — it is a question of *when*, and whether you will detect it in time. A **server compromise** occurs when an unauthorised party gains access to a system in a way that was not intended, permitted, or ex…
publisher: Web Pulse
keywords: cybersecurity
citation: CreativeWork