Files
Anthropic-Cybersecurity-Skills/skills/hunting-credential-stuffing-attacks/SKILL.md
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mukul975 886658219f Add MITRE Fight Fraud Framework (F3 v1.1) mappings to fraud-relevant skills
- Add mitre_f3 frontmatter block to 94 fraud-relevant skills (phishing,
  account takeover, banking malware, BEC, identity/KYC, payment/card fraud,
  money-mule/cash-out, ransomware extortion, DFIR, threat intel)
- Map each skill to F3 v1.1 tactics + precise technique IDs, including the
  two F3-specific tactics ATT&CK lacks: Positioning (FA0001) and
  Monetization (FA0002)
- All 123 F3 v1.1 technique IDs validated against the upstream STIX bundle
  (github.com/center-for-threat-informed-defense/fight-fraud-framework):
  0 invalid IDs, 0 invalid tactics, 0 name mismatches, no placeholder IDs
- mitre_f3 kept as a separate block from mitre_attack (F3 redefines several
  ATT&CK tactics for the fraud context)
- Add docs/mitre-f3-mapping.md schema reference
- Update README: F3 as the 6th framework, dedicated F3 section + badge
2026-06-20 16:06:04 +02:00

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Markdown

---
name: hunting-credential-stuffing-attacks
description: 'Detects credential stuffing attacks by analyzing authentication logs
for login velocity anomalies, ASN diversity, password spray patterns, and geographic
distribution of failed logins. Uses statistical analysis on Splunk or raw log data.
Use when investigating account takeover campaigns or building detection rules for
auth abuse.
'
domain: cybersecurity
subdomain: security-operations
tags:
- credential-stuffing
- authentication-logs
- login-anomaly
- asn-analysis
- threat-hunting
- account-takeover
version: '1.0'
author: mahipal
license: Apache-2.0
nist_csf:
- DE.CM-01
- RS.MA-01
- GV.OV-01
- DE.AE-02
mitre_attack:
- T1078
- T1190
- T1059
- T1003
- T1110
mitre_f3:
version: '1.1'
tactics:
- initial-access
- positioning
techniques:
- id: T1110.004
name: 'Brute Force: Credential Stuffing'
tactic: initial-access
source: attack
- id: T1110.003
name: 'Brute Force: Password Spraying'
tactic: initial-access
source: attack
- id: F1006.002
name: 'Account Takeover: Exposed Login Credential'
tactic: initial-access
source: f3
- id: F1006
name: Account Takeover
tactic: initial-access
source: f3
---
# Hunting Credential Stuffing Attacks
## When to Use
- When investigating security incidents that require hunting credential stuffing attacks
- When building detection rules or threat hunting queries for this domain
- When SOC analysts need structured procedures for this analysis type
- When validating security monitoring coverage for related attack techniques
## Prerequisites
- Familiarity with security operations concepts and tools
- Access to a test or lab environment for safe execution
- Python 3.8+ with required dependencies installed
- Appropriate authorization for any testing activities
## Instructions
Analyze authentication logs to detect credential stuffing by identifying patterns
of distributed login failures, high IP diversity, and suspicious ASN distribution.
```python
import pandas as pd
from collections import Counter
# Load auth logs
df = pd.read_csv("auth_logs.csv", parse_dates=["timestamp"])
# Credential stuffing indicator: many IPs trying few accounts
ip_per_account = df[df["status"] == "failed"].groupby("username")["source_ip"].nunique()
accounts_under_attack = ip_per_account[ip_per_account > 50]
```
Key detection indicators:
1. High unique source IPs per failed username
2. Low success rate across many accounts (< 1%)
3. ASN concentration from cloud/proxy providers
4. Geographic impossibility (same account, distant locations)
5. User-agent uniformity across distributed IPs
## Examples
```python
# Password spray: one password tried across many accounts
spray = df[df["status"] == "failed"].groupby(["source_ip", "password_hash"]).agg(
accounts=("username", "nunique")).reset_index()
sprays = spray[spray["accounts"] > 10]
```