RB-ANALYSIS-024: LOLBin Abuse Investigation

Document Control

1. Prerequisites

Before starting this runbook, ensure the following:

• Access to EDR telemetry
• Access to SIEM telemetry
• Process execution logs available
• Command-line logging enabled
• Endpoint hostname identified
• User context identified
• Incident ticket created

2. Step-by-Step Instructions

1. Identify LOLBin Usage

   Determine whether execution involved a Living-Off-the-Land Binary (LOLBin).

   Common examples include:

   • powershell.exe
   • cmd.exe
   • rundll32.exe
   • regsvr32.exe
   • mshta.exe
   • wmic.exe
   • certutil.exe
   • bitsadmin.exe
   • cscript.exe
   • wscript.exe
   • installutil.exe
   • msbuild.exe
   • schtasks.exe
   • net.exe
   • net1.exe

   Document all observed LOLBins.

2. Collect Execution Context

   Collect:

   • Full command line
   • Parent process
   • Child processes
   • Execution path
   • User context
   • Hostname
   • Execution timestamp

   Review:

   • Process ancestry
   • Associated activity
   • Related alerts

3. Analyse Parent-Child Relationships

   Review:

   • Initial execution source
   • Office application spawning LOLBins
   • Browser spawning LOLBins
   • Script interpreter spawning LOLBins
   • Service-based execution

   Identify suspicious execution chains.

   Examples:

   • winword.exe → powershell.exe
   • outlook.exe → cmd.exe
   • chrome.exe → mshta.exe
   • excel.exe → rundll32.exe

4. Review Command-Line Activity

   Analyse:

   • Download activity
   • Remote resource access
   • Encoded commands
   • Obfuscated content
   • DLL loading
   • Script execution
   • Registry modifications

   Review for common attacker tradecraft.

5. Assess LOLBin Purpose

   Determine whether LOLBin was used for:

   • Execution
   • Persistence
   • Credential access
   • Discovery
   • Lateral movement
   • Data staging
   • Data exfiltration
   • Defence evasion

   Document findings.

6. Review Network Activity

   Identify:

   • Outbound connections
   • Downloaded payloads
   • Cloud storage access
   • Suspicious domains
   • External IP addresses

   Correlate network activity with execution events.

7. Hunt for Additional LOLBin Activity

   Search for:

   • Similar command lines
   • Same LOLBin usage
   • Same user activity
   • Same parent process
   • Same destination infrastructure

   Expand investigation scope where required.

8. Determine Legitimacy

   Validate:

   • Approved administrative activity
   • IT operations usage
   • Security tooling activity
   • Software deployment activity
   • User-authorised execution

   Document rationale for determination.

9. Escalate if Required

   If evidence supports another incident type:

   Activate:

   • PB-003 Endpoint Malware
   • PB-004 Account Takeover
   • PB-005 Data Exfiltration
   • PB-009 Privilege Escalation
   • PB-010 Lateral Movement

   Continue executing current playbook concurrently.

10. Update Incident Record

    Record:

    • LOLBins identified
    • Execution chains
    • Command-line findings
    • Associated activity
    • ATT&CK mappings
    • Escalation decisions

    Attach supporting evidence.

3. Post-Action

Upon completion:

• Ensure all LOLBin activity has been documented
• Ensure command-line evidence is preserved
• Ensure investigation scope has been assessed
• Ensure escalation decisions are recorded
• Ensure incident ticket is updated

Contributor

Vishal Thakur GitHub: https://github.com/malienist

Contributed to the Arcana Incident Response Documentation Framework.