Sherlocked Security – Credential Stuffing & ATO Simulation

Simulating Real-World Attacks to Detect Vulnerabilities in Account Takeover Defenses

1. Statement of Work (SOW)

Service Name: Credential Stuffing & ATO (Account Takeover) Simulation
Client Type: Organizations with User Login Systems, E-Commerce Platforms, SaaS Providers
Service Model: Penetration Testing + Credential Stuffing Simulation + Risk Assessment
Compliance Coverage: GDPR, SOC 2, PCI-DSS, ISO 27001, NIST 800-53

Testing Areas:

Credential Stuffing Attack Simulation
Account Takeover (ATO) Risk Assessment
Brute Force and Password Spraying Tests
Multi-Factor Authentication (MFA) Evasion Techniques
API & Session Security Testing

2. Our Approach

[Credential Leak Discovery] → [Attack Vector Identification] → [Credential Stuffing Simulation] → [MFA & Login Evasion Testing] → [Account Hijacking & Session Management Review] → [Risk Assessment & Mitigation Plan]

3. Methodology

[Reconnaissance] → [Password List & Leak Analysis] → [Attack Simulation (SAST+DAST)] → [MFA Challenge Testing] → [Session Hijacking & Token Analysis] → [Report Generation & Recommendations]

4. Deliverables to the Client

Credential Stuffing Attack Simulation Results
Account Takeover (ATO) Risk and Impact Assessment
Brute Force and Password Spraying Test Results
MFA & Login Bypass Testing Report
API and Session Management Vulnerability Findings
Remediation Plan for Account Security Enhancements
Recommendations for Stronger Authentication and Session Management

5. What We Need from You (Client Requirements)

Access to user login system (test accounts, staging/production environments)
Information on authentication mechanisms (MFA, CAPTCHA, rate limiting)
Credentials or valid user accounts for testing purposes (with proper permissions)
Information on session management protocols (JWT, cookies, token lifespan)
Any pre-configured security policies, such as account lockout policies
NDA and scope confirmation

6. Tools & Technology Stack

Credential Stuffing Tools: Sentry MBA, Snipr, RUA, Burp Suite
MFA Bypass Tools: Evilginx2, Modlishka, Hydra
Brute Force & Password Cracking: John the Ripper, Hashcat
Session Management Testing: Burp Suite, OWASP ZAP, Postman
Account Takeover Attack Simulation: Burp Suite Intruder, Hydra
Reconnaissance: Have I Been Pwned, Dehashed, OSINT tools

7. Engagement Lifecycle

1. Pre-Engagement & Information Gathering → 2. Reconnaissance → 3. Attack Simulation → 4. Testing of MFA & Bypass Methods → 5. Session Hijacking & Token Testing → 6. Vulnerability Assessment & Report Generation → 7. Post-Testing Recommendations & Retest

8. Why Sherlocked Security?

Feature	Sherlocked Advantage
Advanced Credential Stuffing Testing	Simulate large-scale, real-world credential stuffing attacks to identify system weaknesses
MFA Evasion Techniques	Use advanced techniques to bypass multi-factor authentication methods, including phishing-resistant solutions
API & Session Management Testing	In-depth testing of API endpoints, JWT handling, session fixation, and token expiration mechanisms
Realistic Attack Scenarios	Mimic real-world ATO tactics, including password spraying, brute-forcing, and account hijacking
Remediation-Ready Reports	Provide actionable, prioritized recommendations to improve login security and reduce attack surface

9. Real-World Case Studies

E-Commerce Account Takeover

Issue: Attackers successfully used stolen credentials to perform automated login attempts, targeting user accounts with weak passwords.
Impact: Accounts were taken over, leading to fraudulent purchases and stolen payment information.
Fix: Implemented stronger password policies, enforced MFA for all sensitive actions, and introduced CAPTCHA to prevent automated login attempts.

SaaS Platform Password Spraying Attack

Issue: A SaaS platform was vulnerable to password spraying attacks due to the lack of rate limiting and IP-based blocking.
Impact: Attackers gained access to multiple user accounts using common password patterns.
Fix: Added account lockout after multiple failed attempts, integrated rate-limiting mechanisms, and enforced MFA for all users.

10. SOP – Standard Operating Procedure

Reconnaissance & Information Gathering
- Gather publicly available data (e.g., emails, usernames, breached password lists) to identify potential attack vectors.
- Perform OSINT (Open Source Intelligence) gathering to acquire lists of valid usernames and previously leaked credentials.
Credential Stuffing Simulation
- Use common credential stuffing tools to simulate login attempts with breached usernames and passwords (both from known breaches and custom-generated lists).
- Test against both internal systems (web applications, login APIs) and external services (third-party apps, integrations).
Brute Force & Password Spraying Testing
- Implement brute force and password spraying attacks against weak or common passwords.
- Test login attempts against different usernames using common password lists to detect if weak credentials are being used.
MFA & Login Evasion Testing
- Test various MFA bypass techniques, such as phishing-resistant MFA evasion, session hijacking, and the use of man-in-the-middle tools like Evilginx2.
- Attempt to bypass MFA using SIM swapping or social engineering attacks.
Session Hijacking & Token Testing
- Test for session fixation vulnerabilities by attempting to hijack active sessions or impersonate valid users using session tokens.
- Review the lifespan of session tokens (JWT, cookies) and verify that they are invalidated after logout or expiration.
- Check for secure cookie flags, SameSite cookie attributes, and secure token storage practices.
Reporting & Recommendations
- Generate a detailed report on vulnerabilities found, including the success rate of credential stuffing and ATO attacks.
- Provide prioritized recommendations on improving account security, including enhanced authentication mechanisms, session management policies, and user education strategies.

11. Credential Stuffing & ATO Simulation Checklist

1. Reconnaissance & Information Gathering

Use Have I Been Pwned or Dehashed to gather compromised credentials associated with your user base.
Identify common username patterns (e.g., firstname.lastname, employeeID) used by your organization.
Collect details about public-facing login portals and APIs that might be susceptible to credential stuffing.

2. Brute Force & Password Spraying Attacks

Brute Force Testing: Test the system’s resistance to brute force attacks using tools like Hydra, Burp Suite Intruder, or John the Ripper.
Password Spraying: Test the system against password spraying attacks by attempting to login with a small set of commonly used passwords across a wide set of usernames.
Rate Limiting & Account Lockout: Test whether the system enforces proper account lockout policies or rate limiting after multiple failed login attempts.

3. MFA & Login Evasion Techniques

MFA Evasion: Attempt to bypass MFA using phishing-resistant tools like Evilginx2 or Modlishka, which intercept and relay MFA tokens.
SIM Swapping & Social Engineering: Simulate SIM swapping or social engineering attacks to gain access to a victim’s MFA credentials.
Test MFA Bypass Logic: Verify if fallback methods (e.g., email-based MFA or SMS) can be bypassed by an attacker.

4. Session Hijacking & Token Management

Session Fixation: Test whether attackers can hijack or fix user sessions by manipulating session IDs or tokens.
Token Expiry: Verify that session tokens (e.g., JWTs) are properly invalidated after logout and have short expiry times.
Secure Cookie Flags: Ensure that cookies are configured with the HttpOnly, Secure, and SameSite flags to prevent theft via JavaScript or cross-site request forgery (CSRF) attacks.
Session Hijacking: Attempt to hijack active sessions by intercepting cookies or session tokens via techniques like man-in-the-middle attacks or Cross-Site Scripting (XSS).

5. Account Takeover Simulation

Credential Stuffing Attack: Simulate credential stuffing by using a combination of known breached passwords and usernames.
Account Hijacking Attempts: Test the ability to take over an account using compromised credentials and identify any flaws in password reset, MFA, or session management mechanisms.
API Security Testing: If using APIs for user authentication, ensure that they are properly protected from credential stuffing and brute force attempts by using rate limiting and reCAPTCHA or other challenge mechanisms.

6. Reporting & Remediation

Document all findings, including the tools used, attack scenarios, and vulnerabilities discovered.
Provide detailed remediation steps for each vulnerability, focusing on improving login mechanisms, enhancing MFA protections, and bolstering session management.
Include recommendations for security policy enhancements, such as account lockout thresholds, password complexity requirements, and user awareness training.

Credential Stuffing & ATO Simulation