Threat Hunting for Pre-Ransomware Indicators: Signs of Staging and Reconnaissance

I. Executive Summary: Shifting Left of Encryption—The Business Imperative

I.A. The Evolving Threat Landscape: Beyond Simple Disruption

Modern ransomware campaigns represent a significant evolution beyond the simple denial-of-service or system encryption models of the past. Today, ransomware operations function as highly sophisticated criminal enterprises that prioritize maximizing financial and reputational damage. This operational shift has led to the ubiquitous adoption of the double-extortion model, where attackers not only encrypt systems to disrupt operations but also exfiltrate sensitive data and threaten its public release.

The economic and reputational consequences associated with these attacks are substantially higher than those resulting from operational downtime alone. Data extortion introduces legal liabilities, regulatory fines, and long-term erosion of client trust, transforming a temporary IT incident into a systemic business crisis. Because successful attacks require the threat actor to maintain a silent presence within the network for days or weeks—known as dwell time—the most effective defense lies in active threat hunting. Threat hunting is a proactive cybersecurity approach that seeks out the subtle traces left by malicious actors before they can execute the high-impact phase of the attack (encryption and exfiltration).

Crucially, the effectiveness of threat hunting can be framed directly in terms of business value: quantifying avoided loss. While security teams often struggle to demonstrate value when defenses are successful , the proactive identification and elimination of threats during the staging phase directly reduces the Likelihood of a catastrophic security event. By preventing the progression from initial access to domain-wide control, threat hunting preserves brand integrity and mitigates high-stakes data breaches, thereby reducing quantifiable organizational Residual Risk. This active intervention transforms the security function from a reactive cost center into a strategic component that actively manages and reduces corporate risk exposure.

I.B. The Value Proposition: Translating Technical Vulnerability into Business Risk

For cybersecurity activities to gain executive support, they must be communicated using the language of risk management, focusing on metrics such as Likelihood, Vulnerability, Impact, and Risk Mitigation. Threat hunting formalizes the strategic mandate of operating under the assumption that a compromise has already occurred. This mindset is essential, as standard security products, reliant on known signatures or simple rule sets, frequently overlook subtle, anomalous actions performed by sophisticated adversaries.

Threat hunting, paired with advanced Endpoint Detection and Response (EDR) and Network Detection and Response (NDR) solutions, moves the corporate defense posture toward continuous monitoring. This approach actively seeks out patterns of activity indicative of staging—specifically, Credential Access (TA0006) and Discovery (TA0007)—which are prerequisites for large-scale ransomware deployment. Interdicting the attack during these quiet phases yields the highest return on investment, fundamentally disrupting the adversary's preparation phase and preventing the materialization of severe consequences.

II. The Anatomy of Pre-Ransomware Staging: Mapping the Attack Kill Chain

The success of a ransomware campaign is predicated on a quiet, methodical preparation phase. Adversaries utilize consistent tactics, techniques, and procedures (TTPs) that precede the final deployment of the encryption payload. Effective threat hunting is based on mapping these subtle traces to the MITRE ATT&CK framework, understanding the "why" (Tactics), the "how" (Techniques), and the specific implementations (Procedures). Focusing resources on detecting unauthorized credential theft and internal network mapping is critical to disrupting the attack before it can achieve domain-wide impact.

The table below summarizes the critical pre-encryption TTPs that security teams must prioritize and the corresponding business value derived from their successful interception.

Table 1: Critical Pre-Ransomware TTPs and Business Impact

MITRE Tactic	Technique (Example TTP)	Adversary Objective	Business Impact Mitigated by Hunting
Discovery (TA0007)	Internal Network Enumeration (T1016)	Mapping critical assets (DCs, file shares), identifying privileged users.	Prevents efficient lateral movement and reduces the scope of the potential blast radius.
Credential Access (TA0006)	OS Credential Dumping: LSASS (T1003.001)	Stealing high-privilege credentials (Domain Admin) to gain domain control.	Eliminates the foundation for pervasive lateral movement and subsequent domain-wide encryption.
Execution (TA0002)	Service Installation (T1050) / Scheduled Task (T1053)	Establishing persistent backdoors, scheduling cleanup, or setting up encryption/exfiltration processes.	Blocks attacker persistence and disrupts the final phase of the attack (Impact).

II.B. Deep Dive I: Hunting for Credential Dumping (T1003)

Credential Access, particularly the technique of OS Credential Dumping (T1003), is a foundational step for nearly all successful modern ransomware campaigns. The primary target is the Local Security Authority Subsystem Service (lsass.exe), which temporarily stores critical authentication material—including password hashes, clear-text passwords, and Kerberos tickets—in its process memory after a user logs on. Harvesting this material enables lateral movement and privilege escalation, establishing the necessary access rights for domain-wide impact.

Adversaries typically employ two sophisticated methods to achieve this goal. The first involves using custom or publicly available tools, such as Mimikatz, to access the LSASS process memory directly. Mimikatz accesses the LSASS process handle, locates the memory sections storing credentials, and decrypts them. The second method, increasingly favored for its stealth, involves using legitimate Windows utilities—known as Living Off the Land (LotL) techniques—such as procdump.exe or SQLDumper.exe. These legitimate tools are leveraged by attackers to create a file copy of the LSASS memory space (an lsass.dmp file). This dump file is then typically staged internally or exfiltrated for offline analysis, significantly reducing the chance of detection on the host endpoint.

Effective detection cannot rely solely on blocking known malware signatures. The detection strategy must focus on behavioral anomalies surrounding critical system processes. This requires monitoring four key areas: execution telemetry (processes and command lines), file creation events, unauthorized process access, and registry targeting.

A crucial dependency for successful credential dumping detection is the underlying configuration of host logging. The primary telemetry source for execution events is Windows Event ID 4688 (Process Creation). While capturing process start events is standard, the effectiveness of this log is severely limited unless command-line logging is explicitly enabled via Group Policy Object (GPO). Without the full command-line arguments, an analyst will only observe that a utility like procdump.exe or powershell.exe was executed. They cannot determine that the tool was explicitly instructed to target lsass.exe and output the results to a specific location (c:\temp\lsass.dmp). This administrative oversight creates a significant visibility gap—a systemic blind spot—where legitimate LotL tools can operate unimpeded. Therefore, ensuring adequate log configuration is not merely a technical task but a critical mandate for the C-suite to reduce attack surface and validate security investments.

Table 2 details the specific telemetry requirements necessary to detect T1003 procedures effectively.

Table 2: Telemetry Required for Credential Dumping Detection (T1003)

Detection Goal	Telemetry Source	Event ID / Artifact	Detection Rationale
Tool Execution (LotL)	Windows Security Log	4688 (Process Creation with Command Line)	Captures the execution path and arguments of dumping tools (procdump -ma lsass.exe).
Credential File Staging	Sysmon	Event ID 11 (FileCreate)	Indicates the creation of large memory dump files (e.g., lsass.dmp) in unusual locations (e.g., user profiles, temp directories).
Persistence Establishment	Windows Security Log	4697 (Service Installation)	Flags attempts to install credential-harvesting tools or backdoors as persistent services for later access.
LSASS Interaction	EDR/Custom Hooking	Process Access (Read/Write)	Monitors for unexpected processes attempting to open the lsass.exe process handle with high-privilege access.
Registry Targeting	Windows Registry Audit	Unauthorized access to the SAM registry key (*\SAM)	Detects attempts to dump hashed credentials directly from the SAM database.

II.C. Deep Dive II: Hunting for Internal Enumeration and Reconnaissance (Discovery TA0007)

Following credential theft, or sometimes preceding it, an adversary conducts thorough internal reconnaissance to map the network environment. Active Directory (AD) is the central intelligence source for an attacker, providing a detailed blueprint of users, groups, security policies, and potential lateral movement paths. The objective is to identify Domain Controllers, file shares, high-value data repositories, and, most importantly, highly privileged accounts (e.g., Domain Admins) whose compromise will guarantee total network control.

Adversaries employ both well-known and highly stealthy techniques for this discovery phase. Standard practices include running built-in Windows network discovery commands (netscan, nltest, netview)  or using popular open-source tools like BloodHound and SharpHound, which rely heavily on high-volume Lightweight Directory Access Protocol (LDAP) queries to collect domain structure information.

A more advanced, operationally secure technique involves leveraging legitimate Microsoft mechanisms to bypass traditional LDAP monitoring. Attackers can utilize Active Directory Web Services (ADWS), a service exposed on Domain Controllers (DCs) over TCP port 9389, to query AD information using the SOAP protocol. This technique uses mechanisms intended for legitimate administrative tools (like Remote Server Administration Tools or RSAT) and can often evade security tools focused narrowly on traditional LDAP traffic.

The primary defensive measure against internal reconnaissance must be shifting from simple signature detection to establishing and monitoring behavioral baselines. Since standard domain users inherently possess the read access required to query directory data via LDAP , security monitoring must focus on volume and context rather than access permissions alone. Sudden spikes in LDAP queries, port scans , or suspicious administrative tool usage originating from non-Domain Controller hosts are strong indicators. Specifically, queries attempting to retrieve an excessively large number of objects (e.g., querying all users or all group memberships) or queries originating from endpoints (like a desktop PC in the HR department) that rarely interact heavily with the DC are highly suspicious. Specialized Identity Protection solutions, integrated with Network Detection and Response (NDR) tools, are required to effectively monitor traffic between internal systems and detect these subtle, often high-volume, reconnaissance patterns.

III. Threat Hunting Playbook: Practical Scenarios and Analyst Practice

The objective of a formalized threat hunting playbook is to provide repeatable, structured procedures that enable security operations teams to proactively validate hypotheses and mitigate identified threats, concluding with continuous improvement of defenses. To build real analytical proficiency, analysts must train on scenarios that replicate actual attacker TTPs using realistic, synthetic Indicators of Compromise (IOCs).

III.A. Core Principles of the Hunting Cycle

The effective hunting cycle moves systematically from intelligence to action:

1. Hypothesis Generation: Starting with external threat intelligence (e.g., known TTPs of high-profile ransomware gangs) or internal anomalous alerts.

2. Data Acquisition and Analysis: Collecting and correlating telemetry across host (EDR/Sysmon), network (NDR), and identity sources. This is the phase where analysts connect discrete events—such as a short-lived malicious process  with the resulting file creation  and subsequent network connection.

3. Resolution and Continuous Improvement: Isolating compromised assets, removing malware artifacts, and leveraging findings to refine security policies, update detection rules, or implement architectural changes (e.g., micro-segmentation).

III.B. Playbook Scenario A: LSASS Dump Detection and Containment (T1003.001 Focus)

This scenario tests the ability of an analyst to detect credential dumping utilizing a LotL binary and stage the resulting credentials for later use, requiring correlation between process execution and file system activity.

Hypothesis: An unauthorized user executed a living-off-the-land utility (procdump) to dump LSASS memory on a critical server, staging credentials for lateral movement.

Hunting Query Concept (High-Level Search Syntax):

The analyst should search for process execution events involving LotL binaries targeting LSASS memory:

Search: (event_id="4688" OR sysmon_id="1") 

AND (process_name="procdump*.exe" OR process_name="sqldumper.exe") 

AND (command_line CONTAINS "lsass.exe" AND command_line CONTAINS ".dmp")

Analyst Pivots and Investigation Steps:

1. Confirm Execution and Arguments: Use Event ID 4688 to confirm the full command line, specifically verifying the presence of -ma lsass.exe, which indicates the intent to copy the process memory. Note the user account and source hostname (WKS-FIN-01).

2. Confirm File Staging: Pivot immediately to Sysmon Event ID 11 (File Create). Use the Process ID identified in step 1 to confirm the creation of the resulting output file (lsass.dmp). Confirm the file size is significant (e.g., >1GB), consistent with a full memory dump. Note the file's unusual location (e.g., C:\temp).

3. Validate Lateral Movement/Exfiltration: Based on the synthetic log, pivot to network telemetry (NDR) to detect the subsequent SMB session originating from the compromised workstation (WKS-FIN-01) transferring the large dump file to an internal staging server (FILE-STAGING-SRV). Finally, check for the reuse of highly privileged credentials via successful RDP logons (Event ID 4624) on the Domain Controller (DC-01) within minutes of the dump event.

Synthetic Telemetry Example (Scenario A: LSASS Dump)

Time	Log Source	Event ID / Type	Source/Target	Artifact Detail (Synthetic IOC)	TTP / Rationale
14:35:01	Windows Security Log	4688 (Process Creation)	User: SVC_Backup_Runner on WKS-FIN-01	New Process: C:\Windows\Temp\procdump64.exe -ma lsass.exe c:\temp\lsass.dmp	Execution of known credential dumping tool (LotL). T1003.001.
14:35:02	Sysmon	11 (File Create)	Process ID: 3456	Target File: C:\temp\lsass.dmp (Size: 1,245,760 KB)	Confirmation of memory export activity, generating a dump file for offline analysis.
14:35:15	Network Log (NDR)	SMB Session Start	Source: WKS-FIN-01 -> Target: FILE-STAGING-SRV	Large SMB write initiated from WKS-FIN-01 to an internal staging share.	Lateral staging of the stolen credential file before exfiltration or final execution.
14:45:00	Windows Security Log	4624 (Successful Logon)	Source: WKS-FIN-01 -> Target: DC-01	Account: DOMAIN\JSmith (Admin); Logon Type: 10 (RDP)	Immediate reuse of stolen credentials for privileged access (Lateral Movement). T1021.

III.C. Playbook Scenario B: Anomalous Active Directory Enumeration

This scenario focuses on detecting the preparatory network reconnaissance phase, which relies on high-volume queries or unusual administrative commands.

Hypothesis: An attacker is performing excessive and non-standard LDAP queries against the Domain Controller to map the Active Directory structure and identify high-value targets (T1087.002).

Hunting Query Concept (High-Level Search Syntax):

The analyst should search for sudden increases in directory service query activity originating from unexpected hosts:

Search: (log_type="AD_LDAP_Query" OR network_traffic_protocol="LDAP") 

AND (source_host!= DC-*) 

| GROUP BY source_host, queried_object_type 

| WHERE count >

Analyst Pivots and Investigation Steps:

1. Confirm Suspicious Execution: Review Windows Event ID 4688 on the source endpoint (WKS-HR-04) for execution of suspicious tools or encoded PowerShell commands (Base64) often used to launch enumeration scripts.

2. Analyze Query Volume and Content: Pivot to the Domain Controller or Identity Protection logs. Identify the sharp increase in query volume, particularly when targeting highly sensitive security groups (e.g., Domain Admins). Such behavior is highly indicative of automated reconnaissance tools like SharpHound or similar custom scripts.²⁰

3. Identify Post-Reconnaissance Actions: Confirm whether the endpoint followed enumeration with network discovery techniques. Check NDR logs for subsequent low-and-slow port scanning activities (TCP 135, 445, 3389) targeting neighboring hosts or critical servers (HR-DB-SRV). This confirms the attacker is actively utilizing the collected AD intelligence to plot lateral movement paths.

Synthetic Telemetry Example (Scenario B: Enumeration)

Time	Log Source	Event ID / Type	Source/Target	Artifact Detail (Synthetic IOC)	TTP / Rationale
10:12:05	Windows Security Log	4688 (Process Creation)	User: jsmith on WKS-HR-04	Command Line: powershell.exe -e JABHAGUAdAA... (Base64 encoded for AD enumeration)	Execution of suspicious, encoded PowerShell designed for AD collection. T1059.
10:12:08	AD Log / Identity Protection	LDAP Query Alert	Source: WKS-HR-04 -> Target: DC-02	Query: High volume, 500+ unique queries in 60s, targeting group memberships for "Domain Admins," "Enterprise Admins."	Rapid, automated directory reconnaissance, likely via a tool like SharpHound.
10:15:30	Network Log (NDR)	Connection Attempt	Source: WKS-HR-04 -> Target: HR-DB-SRV	Port Scan (TCP 135, 445, 3389) detected over 12 seconds.	Network discovery (port scanning) following AD enumeration, mapping potential lateral movement targets. T1046.

IV. Operationalizing Proactive Defense

Effective security operations must bridge the gap between technical detection and strategic risk management. Proactive threat hunting, when properly operationalized, delivers the actionable intelligence needed to drive systemic defense improvements, significantly lowering the corporate risk posture.

IV.A. Executive Action Checklist: Mandating Visibility and Control

A successful threat hunting program requires executive mandate to ensure the organizational infrastructure supports advanced detection capabilities. Key actions are non-negotiable prerequisites:

1. Mandate Log Hygiene and Data Integrity: Executives must enforce and audit Group Policy Objects (GPOs) to ensure critical host telemetry is collected reliably. Specifically, Windows Event ID 4688 logging must be enabled across all endpoints and servers, including the crucial feature for logging the full command line. The absence of this data renders analysts unable to distinguish between legitimate LotL tool usage and malicious exploitation, creating an organizational blind spot born of administrative failure rather than technical limitation.

2. Invest in Behavioral Monitoring and Identity Protection: Reliance on signature-based defenses is outdated. Investment must prioritize solutions (EDR, NDR, and specialized Identity Protection) capable of establishing behavioral baselines and detecting anomalies. This includes monitoring for unexpected processes accessing sensitive memory areas (LSASS) and analyzing the volume and content of directory service queries (LDAP/ADWS) originating from unusual hosts.

3. Harden Critical Credential Stores: To reduce the Vulnerability associated with T1003, implement strong preventative measures. These include universal enforcement of Multi-Factor Authentication (MFA), strict implementation of the Principle of Least Privilege (PoLP), and comprehensive Active Directory hardening. These foundational controls directly reduce the utility of stolen credentials, mitigating the threat actor's capacity for pervasive lateral movement.

4. Practice and Validate Through Adversary Emulation: The security team must regularly test the effectiveness of their hunting playbooks and detection rules through continuous red teaming and penetration testing. Integrating synthetic IOCs and realistic simulated incidents into continuous analyst training ensures the SOC is capable of quickly analyzing and responding to multi-stage attacks, validating that defenses are functional under real-world pressure.

IV.B. Continuous Improvement: From Detection to Mitigation

The final, critical step in the hunting lifecycle involves leveraging the analyzed TTPs to improve systemic defense mechanisms. When hunting activities consistently reveal that adversaries utilize a specific technique—for instance, dumping credentials using LotL binaries—the mitigation strategy should move beyond simple endpoint removal. It must drive policy updates and architectural changes to reduce the Vulnerability itself.

This process involves translating the observed attacker procedures into actionable prevention controls. If lateral movement often relies on RDP or SMB between segmented zones, micro-segmentation policies should be enforced to restrict default endpoint-to-endpoint communication. By documenting and responding to findings (Resolution), the organization elevates its defenses, transforming transient detection into sustained architectural resilience. This proactive disruption of the staging phase prevents the attacker from achieving their primary objectives—domain control and mass data exfiltration. Ultimately, operationalizing threat hunting provides organizational resilience by systematically reducing the Likelihood of a catastrophic security failure, ensuring that the security function is aligned with the strategic goal of minimizing business risk.