Definition
Breach and attack simulation (BAS) is a type of security tool that automatically runs safe, simulated attacks to check whether security controls detect and block them.
What breach and attack simulation is
Breach and attack simulation (BAS) is a category of security tools that automatically run safe, simulated attacks inside your environment to check whether your security controls detect and block them. Instead of waiting for a real attack to find out whether the firewall, email filter or endpoint protection works, BAS tests them on a schedule.
The core question BAS answers is: are the security controls we paid for actually doing their job today?
How breach and attack simulation works
- Deploy agents or sensors. Lightweight software is installed on selected endpoints, servers or cloud environments, or the tool connects to existing security systems.
- Choose scenarios. The tool offers a library of attack scenarios, usually mapped to MITRE ATT&CK, from phishing payloads and malware behaviour to data exfiltration.
- Run the simulations. Attacks are executed in a controlled way that imitates real techniques without causing damage.
- Check the response. The tool records whether each step was blocked, detected, logged or missed by your security controls.
- Report the gaps. Results show where controls failed, often with guidance on rules or settings to change.
- Repeat. Simulations run continuously or on a schedule, so drift and new gaps are spotted quickly.
What BAS typically tests
- Email security: whether malicious attachments and links are stopped
- Web gateways: whether downloads and connections to malicious sites are blocked
- Endpoint protection: whether malware behaviour and attacker techniques are detected on devices
- Network controls: whether firewalls and segmentation stop movement between systems
- Data loss prevention: whether sensitive data can be sent out of the network
- Detection and logging: whether the SIEM and SOC receive and act on the right alerts
- Cloud controls: whether cloud security settings and monitoring catch common techniques
BAS vs penetration testing vs red teaming
| Breach and attack simulation | Penetration testing | Red teaming | |
|---|---|---|---|
| Main goal | Validate that security controls work | Find and confirm exploitable weaknesses | Test detection and response against a realistic attack |
| How | Automated, pre-built scenarios | Testers or AI agents attack your real systems | Experts pursue an objective while staying hidden |
| Frequency | Continuous or scheduled | Periodic or continuous | Usually once or twice a year |
| Finds new vulnerabilities? | Rarely: focuses on known techniques | Yes: that is its purpose | Yes, on the paths it follows |
| Main output | Control effectiveness and gaps | Confirmed findings and attack paths | Insight into detection, response and resilience |
BAS tells you whether your defences react to known attack behaviour. Penetration testing tells you what an attacker could actually exploit in your environment. The two answer different questions and work well together.
Benefits of BAS
- Continuous validation: controls are checked regularly, not only after an incident or an annual test
- Catches configuration drift: a rule that was changed or a sensor that stopped reporting shows up quickly
- Measures detection coverage: results can be mapped to MITRE ATT&CK to show what the blue team can see
- Safe and repeatable: the same scenario can be run again after a fix to prove it worked
- Supports investment decisions: shows which security tools deliver value and where gaps remain
Limitations of BAS
- Simulated, not real: attacks are designed to be safe, so they do not always behave like a real attacker would
- Limited to known scenarios: BAS checks controls against its library, and rarely discovers new vulnerabilities or misconfigurations in your own applications and systems
- Agent-based coverage: results only apply where agents are deployed
- Does not chain weaknesses: most BAS tools test techniques one by one, rather than following an attack path from entry to target
- Needs follow-up: findings about control gaps still need someone to tune and fix the controls
BAS and continuous threat exposure management
In continuous threat exposure management (CTEM), validation is the stage where an organisation checks which exposures are real and whether its defences would hold. BAS is one of the main tools for this stage, together with penetration testing and red teaming: BAS validates controls, while penetration testing validates exploitability.
How Plainsea helps
BAS checks whether your controls react to known attack techniques. Plainsea answers the other half of the question: what an attacker could actually exploit in your environment. Within the scope you set, AI agents look for weaknesses, try to exploit them and chain them into attack paths, and every finding is confirmed before it reaches your team. Testing can run continuously and fixes can be re-tested on demand, so validated exposures, not just simulated ones, keep shrinking.