Extracting Windows Event Logs Artifacts

Step 2: Run Chainsaw for Sigma-Based Detection

# Install Chainsaw
wget https://github.com/WithSecureLabs/chainsaw/releases/latest/download/chainsaw_all_platforms+rules.zip
unzip chainsaw_all_platforms+rules.zip -d /opt/chainsaw

# Run Chainsaw with bundled Sigma rules
/opt/chainsaw/chainsaw hunt /cases/case-2024-001/evtx/ \
   -s /opt/chainsaw/sigma/rules/ \
   --mapping /opt/chainsaw/mappings/sigma-event-logs-all.yml \
   --output /cases/case-2024-001/analysis/chainsaw_results.txt

# Run with CSV output for easier analysis
/opt/chainsaw/chainsaw hunt /cases/case-2024-001/evtx/ \
   -s /opt/chainsaw/sigma/rules/ \
   --mapping /opt/chainsaw/mappings/sigma-event-logs-all.yml \
   --csv \
   --output /cases/case-2024-001/analysis/chainsaw_results/

# Run with JSON output
/opt/chainsaw/chainsaw hunt /cases/case-2024-001/evtx/ \
   -s /opt/chainsaw/sigma/rules/ \
   --mapping /opt/chainsaw/mappings/sigma-event-logs-all.yml \
   --json \
   --output /cases/case-2024-001/analysis/chainsaw_results.json

# Search for specific keywords
/opt/chainsaw/chainsaw search /cases/case-2024-001/evtx/ \
   -s "mimikatz" --json

# Search for specific event IDs
/opt/chainsaw/chainsaw search /cases/case-2024-001/evtx/ \
   -e 4688 --json | head -100

Step 3: Run Hayabusa for Fast Timeline Generation

# Install Hayabusa
wget https://github.com/Yamato-Security/hayabusa/releases/latest/download/hayabusa-linux-x64-musl.zip
unzip hayabusa-linux-x64-musl.zip -d /opt/hayabusa

# Generate CSV timeline with all detection rules
/opt/hayabusa/hayabusa csv-timeline \
   -d /cases/case-2024-001/evtx/ \
   -o /cases/case-2024-001/analysis/hayabusa_timeline.csv \
   -p verbose

# Generate JSON timeline
/opt/hayabusa/hayabusa json-timeline \
   -d /cases/case-2024-001/evtx/ \
   -o /cases/case-2024-001/analysis/hayabusa_timeline.json

# Run with only critical and high severity detections
/opt/hayabusa/hayabusa csv-timeline \
   -d /cases/case-2024-001/evtx/ \
   -o /cases/case-2024-001/analysis/hayabusa_critical.csv \
   -p verbose \
   --min-level critical

# Generate detection summary (metrics)
/opt/hayabusa/hayabusa metrics \
   -d /cases/case-2024-001/evtx/ \
   -o /cases/case-2024-001/analysis/hayabusa_metrics.csv

# Logon summary
/opt/hayabusa/hayabusa logon-summary \
   -d /cases/case-2024-001/evtx/ \
   -o /cases/case-2024-001/analysis/logon_summary.csv

Step 4: Parse Specific Critical Event IDs

# Extract authentication events with python-evtx
pip install evtx

python3 << 'PYEOF'
import json
from evtx import PyEvtxParser

parser = PyEvtxParser("/cases/case-2024-001/evtx/Security.evtx")

# Critical Event IDs mapping
critical_events = {
    '4624': 'Successful Logon',
    '4625': 'Failed Logon',
    '4634': 'Logoff',
    '4648': 'Explicit Credential Logon',
    '4672': 'Special Privileges Assigned',
    '4688': 'Process Created',
    '4689': 'Process Exited',
    '4697': 'Service Installed',
    '4698': 'Scheduled Task Created',
    '4720': 'User Account Created',
    '4724': 'Password Reset Attempted',
    '4728': 'Member Added to Global Group',
    '4732': 'Member Added to Local Group',
    '4756': 'Member Added to Universal Group',
    '1102': 'Audit Log Cleared',
    '4688': 'New Process Created'
}

results = {eid: [] for eid in critical_events}

for record in parser.records_json():
    data = json.loads(record['data'])
    event_id = str(data['Event']['System']['EventID'])

    if event_id in critical_events:
        event_data = data['Event'].get('EventData', {})
        results[event_id].append({
            'timestamp': data['Event']['System']['TimeCreated']['#attributes']['SystemTime'],
            'event_id': event_id,
            'description': critical_events[event_id],
            'data': event_data
        })

# Print summary
for eid, events in results.items():
    if events:
        print(f"\n[{eid}] {critical_events[eid]}: {len(events)} events")
        for e in events[:3]:
            print(f"  {e['timestamp']}: {json.dumps(e['data'], default=str)[:200]}")
        if len(events) > 3:
            print(f"  ... and {len(events)-3} more")

# Save full results
with open('/cases/case-2024-001/analysis/critical_events.json', 'w') as f:
    json.dump(results, f, indent=2, default=str)
PYEOF

Step 5: Detect Specific Attack Patterns

# Detect Pass-the-Hash (Logon Type 9 with NTLM)
python3 << 'PYEOF'
import json
from evtx import PyEvtxParser

parser = PyEvtxParser("/cases/case-2024-001/evtx/Security.evtx")

print("=== PASS-THE-HASH INDICATORS ===")
print("Looking for: Event 4624, Logon Type 9, NTLM authentication\n")

for record in parser.records_json():
    data = json.loads(record['data'])
    event_id = str(data['Event']['System']['EventID'])

    if event_id == '4624':
        event_data = data['Event'].get('EventData', {})
        logon_type = str(event_data.get('LogonType', ''))
        auth_package = str(event_data.get('AuthenticationPackageName', ''))
        logon_process = str(event_data.get('LogonProcessName', ''))

        # Pass-the-Hash indicators
        if logon_type == '9' and 'NTLM' in auth_package:
            timestamp = data['Event']['System']['TimeCreated']['#attributes']['SystemTime']
            target = event_data.get('TargetUserName', 'Unknown')
            source_ip = event_data.get('IpAddress', 'N/A')
            print(f"  [{timestamp}] PtH: User={target}, IP={source_ip}, Auth={auth_package}")

        # Network logon with NTLM (lateral movement)
        if logon_type == '3' and 'NTLM' in auth_package:
            timestamp = data['Event']['System']['TimeCreated']['#attributes']['SystemTime']
            target = event_data.get('TargetUserName', 'Unknown')
            source_ip = event_data.get('IpAddress', 'N/A')
            workstation = event_data.get('WorkstationName', 'N/A')
            print(f"  [{timestamp}] Network NTLM: User={target}, IP={source_ip}, WS={workstation}")
PYEOF

# Detect log clearing / anti-forensics
python3 << 'PYEOF'
import json
from evtx import PyEvtxParser

for log_file in ['Security.evtx', 'System.evtx']:
    path = f"/cases/case-2024-001/evtx/{log_file}"
    try:
        parser = PyEvtxParser(path)
        for record in parser.records_json():
            data = json.loads(record['data'])
            event_id = str(data['Event']['System']['EventID'])
            if event_id in ('1102', '104'):  # Security log cleared, System log cleared
                timestamp = data['Event']['System']['TimeCreated']['#attributes']['SystemTime']
                print(f"LOG CLEARED: [{timestamp}] EventID {event_id} in {log_file}")
    except Exception as e:
        print(f"Error parsing {log_file}: {e}")
PYEOF

Key Concepts

Tools & Systems

Common Scenarios

Scenario 1: Detecting Lateral Movement Filter for Event 4624 with Logon Type 3 (network) and Type 10 (RDP), identify unusual source-destination pairs, check for Event 4648 (explicit credentials) indicating pass-the-hash, correlate with process creation events (4688) on target systems.

Scenario 2: Privilege Escalation Detection Search for Event 4672 (special privileges assigned) for unexpected users, check for Event 4728/4732 (group membership changes) adding users to admin groups, look for Event 4697 (service installed) indicating new system-level access, correlate with 4720 (account creation).

Scenario 3: PowerShell Attack Detection Analyze PowerShell Operational log for Script Block Logging (Event 4104), search for encoded commands in Event 4688 (process creation with command line), detect AMSI bypass attempts, identify download cradles and invocation of known attack tools.

Scenario 4: Ransomware Incident Reconstruction Build timeline starting from initial access (4624 from external IP), trace privilege escalation through group membership changes, identify service installations for persistence, find process creation events for encryption executable, detect volume shadow copy deletion in System log.

Output Format

Windows Event Log Analysis Summary:
  System: DC01.corp.local (Windows Server 2019)
  Log Files Analyzed: 15 EVTX files
  Total Events: 2,456,789
  Analysis Period: 2024-01-10 to 2024-01-20

  Chainsaw Detections:
    Critical:  12 (Mimikatz usage, PsExec, log clearing)
    High:      34 (Network NTLM logons, encoded PowerShell)
    Medium:    89 (Unusual service installations, scheduled tasks)
    Low:       234 (Informational)

  Hayabusa Timeline:
    Total Alerts: 369
    Unique Rules Triggered: 45
    Top Rules:
      - Suspicious NTLM Authentication (34 hits)
      - PowerShell Download Cradle (12 hits)
      - Service Installation Suspicious Path (8 hits)

  Critical Findings:
    2024-01-15 14:32 - RDP brute force (234 failed, 1 success from 203.0.113.45)
    2024-01-15 14:45 - Admin account created (svcbackup) - Event 4720
    2024-01-16 02:30 - PsExec service installed on DC01 - Event 4697
    2024-01-18 03:00 - Security log cleared - Event 1102

  Reports:
    Chainsaw: /analysis/chainsaw_results/
    Hayabusa: /analysis/hayabusa_timeline.csv
    Critical Events: /analysis/critical_events.json