Anthropic-Cybersecurity-Skills/skills/detecting-pass-the-hash-attacks/references/api-reference.md

API Reference: Detecting Pass-the-Hash Attacks

Windows Event ID 4624 Fields

Field	PtH Signal
LogonType	3 (Network)
AuthenticationPackageName	NTLM (not Kerberos)
LogonProcessName	NtLmSsp
IpAddress	Source of authentication
TargetUserName	Account being used

python-evtx Usage

import Evtx.Evtx as evtx
with evtx.Evtx("Security.evtx") as log:
    for record in log.records():
        xml = record.xml()
        # Filter EventID 4624, LogonType=3, AuthPackage=NTLM

PtH Detection Logic

src_targets = defaultdict(set)
for event in ntlm_logons:
    src_targets[event["source_ip"]].add(event["computer"])
# Alert when single source authenticates to 3+ targets via NTLM

Splunk SPL Detection

index=wineventlog EventCode=4624 Logon_Type=3
| where Authentication_Package="NTLM"
| stats dc(Computer) as targets by Source_Network_Address, Account_Name
| where targets >= 3
| sort -targets

KQL (Microsoft Sentinel)

SecurityEvent
| where EventID == 4624 and LogonType == 3
| where AuthenticationPackageName == "NTLM"
| summarize TargetCount=dcount(Computer) by IpAddress, TargetUserName
| where TargetCount >= 3

Mitigation

# Restrict NTLM authentication
Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Lsa" -Name "RestrictSendingNTLMTraffic" -Value 2

CLI Usage

python agent.py --security-log Security.evtx
python agent.py --security-log Security.evtx --target-threshold 5