Azure ACL vs. RBAC: Navigating Access Control for Better Security

If Azure Authorization had a dramatic TV series, this would be one of those gripping episodes that keeps you thinking about it long after the credits roll. The latest piece in the saga, shared by Disha Verma, explores Azure ACL (Access Control Lists) with refreshing analogies and thought-provoking examples. Let's dissect the chaos of Azure Authorization in this installment, focusing on what ACL is, how it differs from RBAC (Role-Based Access Control), and the unique quirks that make ACL both fascinating and (potentially) frustrating.

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What on Earth is ACL?​

So, what does ACL really do in Azure? Think of ACL as a nutritionist—just like in Disha's analogy of Alpha, Beta, and Gamma at a coffee shop. Every individual customer can have their unique dietary requirements, like avoiding sugar, gluten, or donuts. Similarly, ACL grants specific permissions for resources tailored to individual "dietary" needs. It works independently of whether everyone orders the same coffee or accesses the same resource—each person gets a customized permission list.
More precisely:

• ACL specifies permissions for individual security principals, which may include single users, service principals, or managed identities.
• These permissions are explicit, granular, and identity-specific, making ACL an ideal choice for scenarios with nuanced or complex access requirements.

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Analyzing the RBAC vs. ACL Rivalry​

Now comes the drama! If you've already encountered RBAC (Role-Based Access Control), you might wonder why ACL even exists. Here's the deal:

RBAC: Assign Permissions to the Role​

• Think of RBAC like a broader philosophy for setting access. If you’re organizing a coffee shop (as in the analogy!), you'd assign permissions by role. For instance, “Barista” gets coffee-serving permissions, and everyone in that role—Tracy, Ben, Ross (and their dog, metaphorically)—inherits the same privileges.
• The beauty of RBAC lies in simplicity. One role, one set of permissions—boom, problem solved.

ACL: Customize for Individual Needs​

• This is where ACL steps in with its granular approach. Instead of saying "all Baristas can serve coffee," ACL decides to look at each Barista's personality quirks and needs. Maybe Tracy hates working with vanilla. ACL systems can work in that granularity.

Key Difference? The Scale.

• For small teams or highly specialized tasks, ACL builds customized control down to the individual.
• For larger organizations and widespread responsibilities, RBAC takes the crown because nobody has the time—or patience—to create permissions for "a thousand individual Tracys."

Spoiler alert: RBAC takes precedence over ACL in cases where both systems co-exist. Assigning individual-level permissions sounds perfect until you're drowning in rules for thousands of users.

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How ACL Assigns Permissions​

ACL primarily works at the identity level, which means permissions are tied to users, groups, or even managed identities (e.g., for apps or containers). However, let’s break this down visually. Here's an example scenario:	Use Case	ACL Configuration
Single User, Alpha	Only access resource X, restricted from resource Y.
Group, "Adult"	Permissions grant access to resources X, Y, and Z, tailored to group affiliation.
Service Principal	Apps like Azure Functions or APIs can also have ACL-applied granular permissions.

Just imagine if you’re working in an environment like Azure Data Lake Storage. ACL lets you control who can read, write, or execute files—individually or group-defined. For instance, Tracy (our virtual barista) can work on data with full write access while Ben can only read the reports. It’s tailored access control at its finest.

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Why Does RBAC Trump ACL in Large Workflows?​

Let’s face it—managing ACL across hundreds (or even dozens) of people is complicated. RBAC simplifies the process in situations where organizational roles inherently streamline commonalities. For instance:

• Instead of creating Tracy's ACL rules for managing coffee machines individually, you simply assign her to the "Coffee Manager" role under RBAC.
• This role automatically grants broad permissions for all coffee-related tasks—finer details aren’t necessary.

Essentially, RBAC is your go-to approach when simplicity, consistency, and scalability matter. ACL, on the other hand, is the Michelangelo of customization. It’s there when you need finely detailed control over resources—perfect for unique setups or special scenarios.

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Permission Evaluation in Azure: Showdown Time​

Wonder why RBAC prevails over ACL when they’re used together? This boils down to efficiency. Imagine the coffee shop scenario:

• You don't want to manually say, "Tracy can pour latte, Ben can pour espresso..." That's where RBAC's overarching roles make life easier.
• ACL could override RBAC for granular control—if Microsoft Azure allowed it. But they don’t because consistency dies when systems are overruled too often.

Plus, Azure Permission Evaluation ensures that a user's highest-level permissions (be it RBAC or ACL) remain seamless. Here’s why:

• ACL is resource-specific.
• RBAC assigns broader capabilities.

If the permissions overlap, RBAC manages core responsibilities, while ACL handles nuanced resource tweaks within those boundaries.

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How to Choose Between RBAC and ACL​

Are you facing an authorization conundrum? Ask yourself these:

• Are you working with a few individuals who need tailored, precise access? -> Go ACL.
• Is scalability important, with broad permissions across roles? -> RBAC is the way to rule.

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Takeaway Questions​

After wrapping up this buffet of Azure Authorization concepts, here's a few questions for you to chew on:

• Could ACL replace RBAC in any real-world scenarios, or are these systems destined to co-exist indefinitely?
• How would ACL evolve to tackle growing complexity without overwhelming scalability concerns?
• Are you secretly more of a latte-with-oat-milk person or just here for the espresso?!

Let us know in the comments—for both your Azure challenges and coffee preferences.
If you've followed this trilogy, congratulations! Disha Verma’s delightful breakdowns make digesting tech concepts as easy as sipping your favorite brew. (Almost.) For those looking for even deeper dives, check out Microsoft Documentation on ACLs and RBAC—you might just discover your new favorite hobby: authorization mastery.
Stay tuned for more, as we continue unraveling the chaotic, exciting world of IT management one topic at a time!

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Source: Medium Part 3: Azure Authorization Chaos