Extract, parse, and analyze Windows Event Logs (EVTX) using Chainsaw, Hayabusa, and EvtxECmd to detect lateral movement, persistence, and privilege escalation.
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Extract, parse, and analyze Windows Event Logs (EVTX) using Chainsaw, Hayabusa, and EvtxECmd to detect lateral movement, persistence, and privilege escalation.
# 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 summaryfor 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 indicatorsif 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
Concept
Description
EVTX format
Binary XML-based Windows Event Log format introduced in Vista/Server 2008
Event ID
Numeric identifier for specific event types (e.g., 4624 = successful logon)
Logon types
Classification of authentication methods (2=interactive, 3=network, 10=RDP)
Sigma rules
Generic detection signatures that map to specific SIEM/log queries
Sysmon
Microsoft system monitoring driver providing detailed process and network events
Audit policy
GPO settings controlling which events Windows records
Event forwarding (WEF)
Windows mechanism for centralized event log collection
EVTX channels
Separate log files for different event categories and applications
Tools & Systems
Tool
Purpose
Chainsaw
Sigma-based EVTX analysis and threat hunting tool
Hayabusa
Fast Windows Event Log forensic timeline generator
EvtxECmd
Eric Zimmerman command-line EVTX parser with CSV/JSON output
python-evtx
Python library for EVTX file parsing
LogParser
Microsoft SQL-like query engine for Windows logs
Event Log Explorer
GUI tool for browsing and analyzing EVTX files
KAPE
Automated triage collection including event logs
Velociraptor
Endpoint agent with EVTX collection and hunting artifacts
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.
