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🛡️ What is a CASB?
A Cloud Access Security Broker (CASB) is a security solution positioned between cloud service users and cloud applications. It provides visibility, control, and protection when accessing cloud services like Office 365, Google Workspace, Salesforce, and others.
CASBs help organisations enforce security policies, detect shadow IT, and protect sensitive data across SaaS, PaaS, and IaaS environments.
📌 Key Functions
- Visibility
Gain insight into cloud usage, user behaviours, and unsanctioned apps (shadow IT). - Data Security
Monitor and control data flow using DLP (Data Loss Prevention) policies to prevent unauthorised sharing or exfiltration. - Threat Protection
Detect malware, anomalous activity, and compromised accounts using behavioural analytics. - Compliance Enforcement
Ensure adherence to frameworks like GDPR, ISO 27001, HIPAA by auditing and controlling cloud interactions.
🧰 Common CASB Use Cases
| Use Case | Description |
|---|---|
| Shadow IT Detection | Identify unsanctioned cloud apps in use across the organisation. |
| DLP for SaaS | Prevent sensitive data from being uploaded to or shared via tools like Dropbox or Slack. |
| User Behaviour Monitoring | Detect anomalies like impossible travel or privilege escalation in cloud apps. |
| SaaS Security Posture Management (SSPM) | Check and harden misconfigured settings in services like Microsoft 365 or Zoom. |
🔧 Integration with Other Tools
CASBs often integrate with:
- SIEMs (e.g. Splunk, Sentinel) for centralised logging
- EDR/XDR platforms for endpoint context
- Secure Web Gateways (SWG) and Proxies
- Identity Providers (e.g. Azure AD, Okta) for enforcing conditional access
💡 Leading CASB Vendors
- Microsoft Defender for Cloud Apps (formerly MCAS)
- Netskope
- Zscaler
- Palo Alto Networks (Prisma Access)
- Cisco Cloudlock