Mapping User Permission Hierarchies: A Visual Reverse Engineering Approach to Legacy Modernization

You are staring at a legacy Oracle Forms application that hasn't been documented since 2004. The original developers have retired, the backend logic is a "black box" of nested stored procedures, and the database uses cryptic bitmask flags to handle access control. Yet, you are tasked with migrating this entire system to a modern React-based microfrontend architecture. The biggest hurdle isn't the data migration—it's mapping user permission hierarchies without having a clear map of the existing backend logic.

When documentation is missing (which occurs in 67% of legacy systems according to industry data), and the backend is too fragile to touch, you cannot rely on traditional static analysis. You need a way to extract the "truth" from the only place it still exists: the user interface.

TL;DR: Mapping user permission hierarchies in legacy systems often fails because backend logic is undocumented or inaccessible. By using Replay, a Visual Reverse Engineering platform, architects can record different user personas (Admin vs. Guest) to automatically identify UI deltas. This process converts video recordings into documented React components and permission manifests, reducing the manual audit time from 40 hours per screen to just 4 hours.

The Invisible Debt: Why Permission Mapping Stalls Modernization#

The global technical debt crisis has reached a staggering $3.6 trillion. A significant portion of this debt is locked within "spaghetti" permission logic. In legacy environments, permissions aren't just about who can log in; they dictate field-level visibility, button states, and conditional navigation paths that have been hardcoded over decades.

According to Replay's analysis, 70% of legacy rewrites fail or exceed their timelines primarily because the discovery phase underestimates the complexity of these hidden business rules. When you lack backend access, you are essentially flying blind.

Visual Reverse Engineering is the process of using the visual output of an application—its UI and workflows—to reconstruct the underlying logic, data structures, and component hierarchies without needing to parse the original source code.

The Strategy: Mapping User Permission Hierarchies via UI Deltas#

When the backend is a proprietary silo, the UI becomes your primary source of truth. By observing how the interface changes across different user roles, you can reverse-engineer the permission hierarchy.

1. The Multi-Persona Recording Phase#

To begin mapping user permission hierarchies, you must record the same workflow using different authorization levels. For example, record a "Super Admin" performing a month-end close, then record a "Standard User" attempting the same path.

Video-to-code is the process of using computer vision and AI to transform these recorded user sessions into functional, documented code and architectural blueprints.

2. Identifying the Delta#

By overlaying these recordings, Replay identifies the "Deltas"—the specific elements that disappear, become read-only, or trigger "Access Denied" modals. This visual diffing is the foundation of modern legacy modernization strategies.

3. Synthesizing the Permission Manifest#

Once the deltas are identified, they are grouped into a hierarchical structure. This allows you to move away from legacy bitmasks and toward a modern, declarative Role-Based Access Control (RBAC) system.

Implementing the Modernized Permission Layer#

Once you have successfully completed the stage of mapping user permission hierarchies, the next step is implementation. In a modern React environment, you shouldn't hardcode

throughout your components. Instead, you use the data extracted via Replay to build a centralized Permission Provider.

Below is an example of how the extracted hierarchy is structured in a modern TypeScript/React environment.

Code Example: Defining the Permission Manifest#

typescript
// This manifest is generated based on the Visual Reverse Engineering 
// output from Replay recordings of legacy personas.

export type PermissionAction = 'view' | 'edit' | 'delete' | 'approve';
export type PermissionResource = 'invoices' | 'user_management' | 'reports';

interface UserPermissions {
  role: string;
  grants: {
    [key in PermissionResource]?: PermissionAction[];
  };
}

const permissionManifest: Record<string, UserPermissions> = {
  'SUPER_ADMIN': {
    role: 'Super Admin',
    grants: {
      invoices: ['view', 'edit', 'delete', 'approve'],
      user_management: ['view', 'edit', 'delete'],
      reports: ['view']
    }
  },
  'REGIONAL_MANAGER': {
    role: 'Regional Manager',
    grants: {
      invoices: ['view', 'approve'],
      reports: ['view']
    }
  }
};

Code Example: The React Guard Component#

Using the manifest above, you can wrap your newly generated React components in a guard that mimics the legacy behavior discovered during the mapping process.

tsx
import React, { createContext, useContext } from 'react';

const PermissionContext = createContext<UserPermissions | null>(null);

export const PermissionGuard: React.FC<{
  action: PermissionAction;
  resource: PermissionResource;
  children: React.ReactNode;
  fallback?: React.ReactNode;
}> = ({ action, resource, children, fallback = null }) => {
  const permissions = useContext(PermissionContext);

  const hasAccess = permissions?.grants[resource]?.includes(action);

  if (!hasAccess) {
    return <>{fallback}</>;
  }

  return <>{children}</>;
};

// Usage in a modernized component
const InvoiceActionButtons = () => (
  <div>
    <PermissionGuard action="view" resource="invoices">
      <button>View Invoice</button>
    </PermissionGuard>
    
    <PermissionGuard action="approve" resource="invoices">
      <button className="btn-primary">Approve</button>
    </PermissionGuard>
  </div>
);

The Role of AI in Mapping User Permission Hierarchies#

Industry experts recommend leveraging AI to handle the "heavy lifting" of pattern recognition in legacy UIs. When mapping user permission hierarchies, an AI-driven approach can detect subtle changes that a human auditor might miss—such as a specific menu item that only appears if two different permission flags are set simultaneously.

Replay's AI Automation Suite analyzes the DOM state and visual rendering of legacy applications to categorize these rules. Instead of an 18-month average enterprise rewrite timeline, organizations are seeing completed migrations in weeks. This is achieved by bypassing the need to "re-learn" the legacy backend code and instead focusing on the desired end-state behavior.

From "Flows" to "Blueprints"#

In Replay, the process follows a specific architectural path:

1. •Flows: You record the user journey, capturing every state change.
2. •Library: Replay identifies recurring UI patterns and extracts them into a standardized Design System.
3. •Blueprints: The mapping of user permission hierarchies is formalized here, creating a visual map of what every user type can see and do.

Case Study: Financial Services Modernization#

A global bank faced a challenge with a 15-year-old commercial lending portal. The system had over 400 screens and a complex web of permissions that varied by branch location, loan amount, and officer seniority. There was zero documentation.

By using Replay for mapping user permission hierarchies, the bank's architecture team recorded 12 different user personas. Replay's visual diffing engine identified 85 unique permission nodes that had been buried in the legacy code.

According to Replay's analysis of this project:

• •Manual Estimate: 14 months for discovery and mapping.
• •Replay Actual: 3 weeks for full permission mapping and component extraction.
• •Result: The bank saved approximately $1.2M in labor costs and avoided the "rewrite trap" that claims 70% of such projects.

Security and Compliance in Regulated Environments#

When mapping user permission hierarchies in sectors like Healthcare or Insurance, data privacy is paramount. Mapping permissions visually means you are often handling sensitive PII (Personally Identifiable Information) on screen.

Replay is built for these regulated environments. With SOC2 compliance, HIPAA-readiness, and an on-premise deployment option, enterprise architects can perform visual reverse engineering without sensitive data ever leaving their secure perimeter. This allows for the extraction of architectural "Blueprints" while maintaining strict data sovereignty.

Overcoming the "Documentation Gap"#

The "Documentation Gap" is the primary reason why the average enterprise rewrite takes 18 months. When you are mapping user permission hierarchies, you aren't just looking for roles; you are looking for the intent of the original business logic.

Industry experts recommend a "Capture-First" approach. Instead of trying to read the legacy code, capture the application in motion. This provides a functional specification that is 100% accurate to the current production environment, rather than relying on outdated 2004-era requirements docs.

Learn more about visual reverse engineering and how it is changing the way we approach technical debt.

Frequently Asked Questions#

How can I map permissions if the legacy app has "hidden" features not visible in the UI?#

While visual mapping captures what users can see, it also identifies the absence of elements. By comparing a high-level admin recording with a standard user recording, Replay identifies the "hidden" logic. If a feature is truly hidden from all users, it is likely dead code that shouldn't be migrated anyway—helping you reduce the footprint of your new application.

Does Replay require access to the original source code?#

No. Replay operates on the visual and DOM layer of the application. This makes it ideal for situations where the source code is lost, proprietary, or too complex to parse. It effectively treats the legacy application as a "black box" and extracts the functional requirements through observation.

How does mapping user permission hierarchies visually handle field-level encryption?#

Visual reverse engineering identifies the state of the field (e.g., masked, read-only, or editable). While it doesn't "break" encryption, it documents the logic of when a user is allowed to see the unmasked data, which is the critical component for building the new frontend's permission logic.

Can Replay generate the actual React code for my new Design System?#

Yes. One of the core features of Replay is its ability to convert visual patterns into a documented React Component Library. This ensures that the modernized version of your app doesn't just act like the old one—it uses clean, reusable, and themed code that follows modern best practices.

Conclusion#

The traditional path to modernization is broken. Trying to map user permission hierarchies by digging through decades of undocumented backend code is a recipe for timeline overruns and project failure. By shifting the focus to Visual Reverse Engineering, enterprise architects can gain a clear, documented, and actionable map of their application's logic in a fraction of the time.

Stop guessing what your legacy system does. Use Replay to see it, document it, and modernize it.

Ready to modernize without rewriting? Book a pilot with Replay