What is Breach and Attack Simulation (BAS)? The Complete Guide

Breach and Attack Simulation (BAS) is a cybersecurity testing method that uses automated tools to safely simulate real-world cyberattack techniques against your network and systems. The goal is simple: find out whether your security controls actually detect and prevent the attacks that real adversaries use every day.

Your firewall claims it blocks malicious traffic. Your SIEM claims it detects threats. Your EDR claims it prevents malware. BAS is how you verify those claims.

How Breach and Attack Simulation Works

A BAS platform contains a library of attack modules, each designed to simulate a specific adversary technique. These modules use benign payloads that mimic the behavior patterns of real attacks without causing actual damage:

• A ransomware simulation tests whether your monitoring detects rapid file rename patterns - without actually encrypting any files
• A credential dumping simulation tests whether your SIEM detects LSASS memory access patterns - without extracting any credentials
• A data exfiltration simulation tests whether your DLP catches large outbound transfers - using synthetic data, not real sensitive information
• A phishing simulation delivers benign payloads that mimic malicious attachments - testing email filtering without any actual malware

After running a simulation, the BAS platform reports which attacks were detected (your SIEM, EDR, or other tools triggered an alert), which were blocked (your firewall, endpoint protection, or network controls prevented the technique), and which succeeded undetected (the attack technique completed without any security tool noticing).

That last category - attacks that succeed without detection - is the entire value proposition of BAS. Those are your defense gaps. Those are what real attackers will exploit.

BAS vs. Penetration Testing vs. Red Teaming

BAS, pentesting, and red teaming are all security testing approaches, but they serve different purposes:

BAS doesn't replace pentesting or red teaming. It fills the gap between annual tests with continuous validation. Think of pentesting as your annual physical exam and BAS as your daily fitness tracker.

BAS and the MITRE ATT&CK Framework

The MITRE ATT&CK framework is the standard taxonomy for adversary behavior. It organizes real-world attack patterns into 14 tactics (the attacker's goal) and hundreds of techniques (the specific methods used).

BAS platforms use ATT&CK as their organizing framework. Each attack module maps to one or more ATT&CK techniques. After running simulations, you get an ATT&CK heat map showing:

• Green - Techniques your defenses detected or blocked
• Yellow - Techniques that were partially detected (alert fired but no prevention)
• Red - Techniques that succeeded without detection - your gaps
• Gray - Techniques not yet tested

This heat map becomes your detection engineering roadmap. Red areas need new detection rules. Yellow areas need rule tuning. Green areas need periodic re-validation to prevent regression.

What BAS Tests: Common Attack Techniques

A comprehensive BAS platform simulates techniques across the entire adversary lifecycle:

Initial Access Techniques

• Phishing payload delivery (T1566) - Tests email filtering, attachment scanning, and URL reputation checking
• Credential stuffing (T1110) - Tests account lockout policies, failed login detection, and anomaly detection
• Exploitation of public-facing applications (T1190) - Tests WAF rules, input validation, and vulnerability detection

Post-Compromise Techniques

• Privilege escalation (T1068) - Tests privilege change monitoring and least-privilege enforcement
• Credential dumping (T1003) - Tests endpoint detection of LSASS access and SAM database reads
• Lateral movement via SMB, RDP, WMI (T1021) - Tests network segmentation and authentication monitoring
• Command and control communications (T1071) - Tests DNS monitoring, proxy inspection, and threat intel feed integration

Impact Techniques

• Data exfiltration via DNS tunneling, HTTP, cloud storage (T1048) - Tests DLP, outbound traffic analysis, and data loss detection
• Ransomware file encryption behavior (T1486) - Tests file integrity monitoring and rapid-change detection

Benefits of Breach and Attack Simulation

• Continuous validation - Don't wait for the next pentest to find out your detections are broken. BAS runs on demand or on a schedule, catching regression immediately when infrastructure changes.
• Measurable security posture - Instead of "we think our security is good," you get "we detect 73% of ATT&CK techniques and here are the specific gaps." Board-ready metrics based on empirical testing.
• Detection engineering fuel - Every undetected technique becomes a detection engineering ticket. BAS turns vague "improve security" goals into specific "write a detection rule for T1003.001" tasks.
• Compliance evidence - SOC 2 CC7.1 requires monitoring. NIST SP 800-53 CA-8 specifically requires penetration testing. BAS results serve as evidence that your detection controls are functioning.
• Purple team enablement - BAS provides the attack execution that purple teams need. Run the simulation, analyze results together, write detections, re-test. Structured improvement cycles.
• Cost efficiency - Annual pentests at $50K test a snapshot. BAS at Contact Sales-$200K/year tests continuously. The per-test cost approaches zero as you run more simulations.

Who Needs BAS?

Every organization with security tools they can't validate. If you've deployed a SIEM, EDR, firewall, or any other detection/prevention tool and you don't have a way to verify it's actually working, you need BAS.

BAS is particularly valuable for:

• Small security teams (1-10 people) who can't afford annual pentests but need detection validation
• Organizations pursuing SOC 2, ISO 27001, or NIST compliance that need evidence of continuous monitoring effectiveness
• Teams running SIEM or EDR who want to verify their detection rules actually fire when they should
• Purple team programs that need structured attack execution for collaborative defense improvement
• Security leaders who need to report measurable security posture to the board

Getting Started with BAS

Starting a BAS program doesn't require a six-figure budget. Here's the practical approach:

1. Start with your SIEM - If you have a SIEM (or deploy BTA SIEM for Contact Sales), your first BAS tests should validate whether your detection rules actually trigger. Run brute force, lateral movement, and C2 simulations and check if alerts appear.
2. Map to ATT&CK - Document which techniques you currently detect. Use the MITRE ATT&CK framework to identify gaps. Prioritize gaps based on your threat model.
3. Run monthly simulations - At minimum, run your full simulation suite monthly. After any infrastructure change (new firewall rules, SIEM rule updates, EDR policy changes), run affected simulations immediately.
4. Close gaps iteratively - Each simulation run produces a gap list. Address the highest-risk gaps first. Write detection rules, update configurations, then re-run to verify the fix works.
5. Report progress - Track your ATT&CK detection coverage percentage over time. Show the board a number that goes up as your program matures. "We now detect 85% of ATT&CK techniques, up from 62% last quarter."

BASzy AI delivers 124+ ATT&CK attack modules for Contact Sales, running entirely on your local infrastructure. No cloud dependency. No per-asset fees. Continuous security validation accessible to every team.