Cloud computing has revolutionized modern business, enabling greater agility, scalability and cost savings. However, migrating applications and data to the cloud also introduces new security and compliance risks. Cloud Access Security Broker (CASB) solutions provide the visibility and control to securely embrace cloud adoption.
What is a CASB and Why is it Critical?
A CASB acts as a policy enforcement layer between cloud service consumers and cloud applications. It ensures security policies are applied consistently across an organization‘s cloud footprint.
CASB architecture (Image source: Geekflare)
Without a CASB in place, organizations struggle to gain visibility into shadow IT usage, data breaches go undetected, and threats penetrate unchecked – resulting in million-dollar remediation costs.
In fact, according to IBM, the average cost of a data breach now exceeds $4.35 million.
Meanwhile, over 90% of enterprises now use cloud services, often without IT‘s knowledge or oversight. This expands the attack surface and compliance risks dramatically.
A CASB protects against data leakage, account compromise, malware infections, unsanctioned app usage, regulatory non-compliance and sophisticated cloud-native threats. It acts as the missing layer needed to securely enable cloud adoption at scale.
Key Features and Security Capabilities
CASB solutions consolidate a number of critical cloud security capabilities into a single managed platform:
Cloud Visibility – Discover shadow IT, classify sensitive data, analyze behavior patterns and monitor app configurations. This contextual insight informs policy decisions.
Data Loss Prevention – Encrypt sensitive files, tokenize and mask data fields, set access permissions and quarantine shares to stop data from leaving the organization without authorization.
Threat Protection – Block malware uploads, use threat intel to stop known attacks, detect compromised accounts, filter suspicious web requests and isolate unsafe apps or devices.
Access Controls – Enforce context-aware policies based on user, device and data risk scoring as well as behavior anomalies to restrict actions. Authenticate using SSO and MFA.
Compliance Enforcement – Continuously audit cloud configurations against regulatory frameworks like HIPAA and PCI DSS to avoid violations through misconfiguration. Remediate or be alerted of violations.
Cloud Governance – Model least-privilege permissions aligned to roles, automatically detect over-entitlement risks, and right-size permissions.
Advanced CASB platforms even provide CSPM, CWPP and CIEM capabilities now.
CASB Deployment Models Explained
CASB architecture can vary greatly depending on the provider and deployment scenario chosen. But most adopt one of these common placement models:
Proxy Model
A forward proxy CASB inspects traffic between the cloud app and endpoints by rerouting flows through the CASB server. This facilitiates inspection of encrypted traffic but may impact performance.
API Control Model
With API-based CASBs, cloud app providers allow the CASB to interface directly with their application programming interfaces to enforce policies. This has minimal overhead but relies on the granularity of controls exposed by APIs.
Reverse Proxy Model
In a reverse proxy model, the CASB frontends the cloud app itself, effectively acting as an access control layer. This insertion point allows policy enforcement for both internal and external users.
Hybrid Models
Leading CASB vendors support a hybrid blend of proxy, API and reverse proxy controls based on the application, enabling defense-in-depth.
Common CASB deployment models (Image source: Geekflare)
How Do I Select the Right CASB Solution?
With cloud threats on the rise, interest in CASBs is exploding. All major security vendors now offer a CASB product.
Use this checklist when evaluating options:
Cloud App Support – Assess breadth of app coverage across IaaS, PaaS, SaaS.
Deployment Mode Options – Look for support hybrid, multi-cloud and on-premise use cases.
Data & Threat Protection – Review exploit, malware and DLP capabilities for rigor.
Integration Support – See what adjacent tools can integrate with for consolidation.
Analytics & Reporting – Verify risk frameworks, metrics and dashboards will provide actionable insight.
Ease of Use – Check that policies are simple to configure without heavy coding.
Customer Support – Review responses to common questions as a quality benchmark.
Pricing Structure – Confirm model aligns to business expansion plans.
Here is a high-level comparison of leading CASB platform capabilities:
| CASB Vendor | Data Security | Threat Prevention | Cloud Visibility | Intuitive UI |
|---|---|---|---|---|
| Netskope | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐ |
| Microsoft | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ |
| Bitglass | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐ |
| CipherCloud | ⭐⭐⭐⭐⭐ | ⭐⭐ | ⭐⭐ | ⭐⭐⭐ |
| McAfee | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ |
(5 stars = Excellent, 1 star = Poor)
While Netskope leads on advanced data protection, Microsoft Cloud App Security provides the most holistic feature set. Pick based on your key priorities.
Creating an Effective CASB Security Policy
The most challenging part of rolling out a CASB is defining the appropriate level of control needed to reduce risk exposure without hampering productivity.
Based on deployments for large enterprises, I recommend a stepped policy plan:
1. Discover Shadow IT – Inventory all cloud services in use with discovery scans. Classify risk.
2. Pilot Urgent Apps – Select 2-3 high-risk apps like Dropbox for initial policy enforcement focused on DLP and malware prevention.
3. Expand Controls – Over a 6-12 month period, incrementally apply controls on user types, devices, data and threats for each app based on risk profile.
4. Continual Optimization – Use visibility into blocks and user impact to constantly refine policies around learning.
Do not attempt "big bang" security without context – this tends to fail. Phase based on business impact.
Integrating the CASB into the Security Stack
To maximize value, the CASB should integrate with adjacent security tools like SIEM, firewalls and web proxies via APIs.
Feeding CASB logs enriched with contextual data into the SIEM consolidates cloud insights for better correlation and alerting.
Pairing the CASB and secure web gateway (SWG) creates layered defense between endpoints and the internet.
Synchronizing the CASB with an identity provider facilitates access policy alignment.
Conclusion and Key Recommendations
A comprehensive CASB solution enables safe cloud app adoption by giving control guardrails around sensitive data usage, user actions and threat prevention.
Here are 5 key takeaways when considering CASB security:
1. Audit App Risks First – Discover shadow IT and classify app data sensitivity before enforcement.
2. Phase Policies – Take an iterative approach based on risk appetite.
3. Seek Broad Coverage – Multi-mode CASBs with wide app support provide flexibility.
4. Tap Value-Adds – Leverage for training and cloud governance beyond just security.
5. Integrate for More Protection – Unite with SIEM and proxies for layered defense.
With the right CASB partner, organizations can embrace the cloud safely and accelerate their businesses confidently.
References: IBM Cost of Data Breach Report 2022, Palo Alto Networks 2022 Cloud Threat Report
