Detecting and Investigating Credential Theft: A Forensic Guide Using ThreatResponder

In today’s threat landscape, credential theft remains one of the most powerful weapons in an attacker’s arsenal. Whether it’s the initial compromise or lateral movement across a network, the ability to impersonate legitimate users opens the doors to sensitive systems, data exfiltration, and long-term persistence. Security teams must not only detect such incidents in real time but also perform in-depth forensic analysis to understand the full scope of the breach.

This blog explores how NetSecurity’s ThreatResponder platform and the ThreatResponder Forensics (TRF) tool help security teams detect, investigate, and respond to credential theft with unmatched speed and precision.

Understanding Credential Theft Techniques

Before diving into detection and forensics, it’s essential to understand how attackers typically steal credentials:

1. Dumping LSASS Memory: Attackers use tools like Mimikatz or custom malware to dump the memory of the LSASS process, which contains plaintext credentials and password hashes.

2. NTDS.dit Extraction: This file from a domain controller contains all Active Directory users’ password hashes. It’s highly valuable during post-compromise exploitation.

3. Keylogging & Screen Captures: Malware may log keystrokes or capture screens to harvest credentials entered into browsers or terminals.

4. Token Impersonation & Pass-the-Hash: Once hashes or tokens are captured, attackers can reuse them to authenticate without needing actual passwords.

5. Phishing & Browser Credential Theft: Attackers may use social engineering or exploit browser password managers to extract stored credentials.

The Role of Digital Forensics in Credential Theft Investigations

After an incident, forensic analysis is critical for:

• Identifying the root cause and method of credential compromise.

• Pinpointing which accounts were compromised.

• Understanding the timeline and lateral movement.

• Gathering evidence for response, legal, and compliance requirements.

This is where ThreatResponder and ThreatResponder Forensics (TRF) shine.

Detecting Credential Theft in Real-Time with ThreatResponder

ThreatResponder is a cloud-native, AI-powered cyber-resilient endpoint platform that integrates EDR, DFIR, threat intelligence, and ITDR capabilities into one lightweight agent. Its detection and telemetry features make it highly effective at spotting credential theft techniques, including:

• LSASS Access Monitoring

ThreatResponder monitors for unauthorized attempts to access or dump the memory of the LSASS process. Alerts are generated when suspicious tools (like procdump, comsvcs.dll, or Mimikatz) attempt to read or clone the LSASS memory.

• Detection of Known Credential Dumping Tools

ThreatResponder maintains a rich database of threat intelligence and YARA rules to detect tools like LaZagne, Mimikatz, and custom LSASS dump utilities, even when renamed or obfuscated.

• Anomalous User Behavior Detection

With built-in Identity Threat Detection and Response (ITDR), ThreatResponder monitors abnormal login patterns, failed login spikes, privilege escalation, and logins from unusual IPs or devices.

• In-Memory and Fileless Attack Detection

Credential theft tools often operate in-memory to avoid detection. ThreatResponder’s memory scanner and behavior analytics identify anomalous execution patterns, injected code, and fileless operations tied to credential harvesting.

Post-Incident Forensics with ThreatResponder Forensics (TRF)

When an incident occurs—or if you’re responding after the fact—ThreatResponder Forensics (TRF) is the go-to tool for offline forensic investigations. Available as a free download from NetSecurity’s website, TRF helps security professionals perform deep-dive memory and disk analysis on infected endpoints, even when isolated from the network.

Here’s how TRF aids credential theft investigations:

Memory Analysis for LSASS Dumps

TRF allows investigators to:

• Load memory images and extract indicators of credential theft.

• Identify dumped LSASS processes.

• Extract credentials and understand what was accessed by the attacker.

• Analyze in-memory injections and loaded DLLs.

Disk Artifact Review

Credential stealers often drop artifacts to disk (e.g., .dmp, .log, .bin files). TRF helps you:

• Locate these files.

• Review process creation history.

• Map attacker tools and scripts dropped for later reuse.

Timeline Reconstruction

TRF can correlate event logs, process execution, and network activity to reconstruct the attacker’s timeline—when they dumped LSASS, what account was accessed next, and how the breach unfolded.

Password & Token Analysis

TRF supports decoding and reviewing stolen credential data:

• Analyze stolen token usage.

• Review credential cache artifacts.

• Match credential usage with user behavior analytics.

Real-World Use Case: A Credential Theft Investigation with ThreatResponder

Let’s say your SIEM alerts you to a suspicious LSASS memory access from a non-administrative user account. ThreatResponder flags a process named svhost.exe (misspelled) attempting to read LSASS using comsvcs.dll.

Your team springs into action:

1. Live Detection via ThreatResponder:

   • Alerts indicate credential dumping behavior.

   • Process tree shows the malicious svhost.exe was dropped via a phishing payload.

   • User behavior analysis reveals multiple failed login attempts on other servers.

2. Isolation and Imaging:

   • The affected system is isolated from the network using ThreatResponder.

   • A full memory and disk image is collected.

3. Offline Analysis via TRF:

   • LSASS dump file is discovered.

   • Decoded credentials are cross-referenced with logs.

   • You identify lateral movement using a domain admin’s hash.

4. Remediation and Response:

   • All affected accounts are reset.

   • IOC-based hunting across the environment reveals two more infected machines.

   • Forensic reports generated from TRF aid in post-incident reviews and compliance documentation.

Why It Matters

Credential theft can silently unravel an entire security infrastructure. Attackers armed with stolen credentials can:

• Evade detection.

• Access sensitive systems.

• Deploy ransomware or exfiltrate data.

But with ThreatResponder’s real-time capabilities and TRF’s forensic depth, defenders are better equipped to stop attackers at the credential theft stage—before catastrophic damage occurs.

Try ThreatResponder Today

Credential theft isn’t just a technique—it’s a strategy that skilled attackers use to exploit trust and move undetected. Without visibility into memory, process behavior, and credential usage, organizations remain blind to some of the most critical phases of the attack chain.

By combining ThreatResponder’s AI-powered, real-time detection with TRF’s comprehensive forensic analysis, security teams can detect, investigate, and respond to credential theft faster—and smarter. Learn more about ThreatResponder and schedule a demo with our team today.

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