Welcome back to our Digital Forensics and Incident Response (DFIR) journey. In our last post, we discussed Delivery—how attackers transmit malicious payloads into target environments. Today, we advance to the next stage in the Cyber Kill Chain: Installation.

💾 What is the Installation Phase?

Installation is where the attacker’s payload embeds itself into the victim’s system. The goal is to establish a persistent and often stealthy presence. If the delivery vector was successful—say, a user opened a malicious attachment—then installation ensures the malware executes and integrates into the host environment.

🔧 Common Installation Techniques

• Dropping malware into startup folders or using scheduled tasks
• Modifying registry keys for persistence
• Installing backdoors or Remote Access Trojans (RATs)
• Abusing legitimate tools like PowerShell or WMI
• Leveraging LOLBins (Living Off the Land Binaries) to stay undetected

🛑 Why Installation is Dangerous

Once malware is installed, attackers can operate with a higher degree of control and stealth. Detection becomes much harder—especially if they use obfuscation, encryption, or masquerading tactics. At this stage, it’s not just about stopping an attack—it’s about detecting what’s already landed.

🔍 Defending Against Installation

Organizations must adopt a layered defense approach to catch installation attempts early. This includes:

• Endpoint Detection and Response (EDR): Tools like CrowdStrike, SentinelOne, or Microsoft Defender for Endpoint can monitor for suspicious behaviors.
• Application Control: Use AppLocker or WDAC (Windows Defender Application Control) to block unauthorized executables and scripts.
• Threat Intelligence Feeds: Detect known Indicators of Compromise (IOCs) tied to installer scripts or C2 infrastructure.
• Security Awareness Training: Teach users to recognize phishing attempts and malicious links that lead to installation vectors.
• SIEM/Log Analysis: Correlate system events such as registry modifications, new services, and file writes to unusual locations.

🛠️ Example Toolkits

• Sysmon: Provides detailed system activity logs, such as process creations and file writes
• Autoruns: Detects startup items and persistent mechanisms
• Velociraptor: Enables endpoint visibility and live queries
• Atomic Red Team: Simulates installation techniques to test your defenses
• Splunk: Collects, indexes, and analyzes machine-generated data in real time to support security monitoring, IT operations, and business intelligence.

🧠 Final Thoughts

The Installation phase is a turning point in most intrusions. It marks the shift from opportunity to foothold. As defenders, recognizing and preventing this step is key to stopping threat actors before they pivot deeper into your environment.

In the next part of our series, we’ll explore Command and Control (C2)—the digital umbilical cord between attacker and malware. Until then, keep watching the logs, training your users, and tightening your endpoint defenses.