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Anthropic-Cybersecurity-Skills/skills/detecting-anomalous-authentication-patterns/references/api-reference.md
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mukul975 27c6414ca5 Add folder anatomy (scripts/agent.py + references/api-reference.md) for 648 cybersecurity skills
Complete skill folder anatomy across all cybersecurity skills:
- scripts/agent.py: 80-150 line Python agents using real libraries (impacket,
  boto3, azure-mgmt-*, kubernetes, pefile, yara, scapy, shodan, stix2, etc.)
- references/api-reference.md: real API documentation with method signatures
- LICENSE: MIT license for all skill folders
2026-03-10 21:02:12 +01:00

2.3 KiB

Authentication Anomaly Detection API Reference

Azure AD Sign-In Logs (Microsoft Graph)

# Query sign-in logs
GET https://graph.microsoft.com/v1.0/auditLogs/signIns?$filter=createdDateTime ge 2024-01-01
Authorization: Bearer <token>

# Risky sign-ins
GET https://graph.microsoft.com/v1.0/identityProtection/riskyUsers

Okta System Log API

# Query authentication events
curl "https://your-org.okta.com/api/v1/logs?filter=eventType+eq+%22user.session.start%22&since=2024-01-01" \
  -H "Authorization: SSWS <api_token>"

# Filter failed logins
curl "https://your-org.okta.com/api/v1/logs?filter=outcome.result+eq+%22FAILURE%22" \
  -H "Authorization: SSWS <api_token>"

Windows Event IDs for Auth Monitoring

Event ID Description
4624 Successful logon
4625 Failed logon
4648 Logon with explicit credentials
4672 Special privileges assigned
4768 Kerberos TGT request
4769 Kerberos service ticket request
4771 Kerberos pre-auth failed
4776 NTLM credential validation

Splunk SPL Detection Queries

# Brute force detection
index=auth result="failure"
| bin _time span=10m
| stats count by user src_ip _time
| where count >= 10

# Password spray detection
index=auth result="failure"
| bin _time span=30m
| stats dc(user) as targets count by src_ip _time
| where targets >= 10

# Impossible travel
index=auth result="success"
| iplocation src_ip
| sort user _time
| streamstats last(lat) as prev_lat last(lon) as prev_lon last(_time) as prev_time by user
| eval dist=6371*2*asin(sqrt(pow(sin((lat-prev_lat)*pi()/360),2)+cos(prev_lat*pi()/180)*cos(lat*pi()/180)*pow(sin((lon-prev_lon)*pi()/360),2)))
| eval speed=dist/((_time-prev_time)/3600)
| where speed > 900 AND dist > 100

GeoIP with MaxMind (Python)

import geoip2.database
reader = geoip2.database.Reader('/opt/geoip/GeoLite2-City.mmdb')
response = reader.city('203.0.113.50')
print(response.city.name, response.location.latitude, response.location.longitude)
reader.close()

Isolation Forest (scikit-learn)

from sklearn.ensemble import IsolationForest
model = IsolationForest(n_estimators=200, contamination=0.01, random_state=42)
model.fit(X)
predictions = model.predict(X)  # -1 = anomaly, 1 = normal
scores = model.score_samples(X)  # lower = more anomalous