What is Broken Object Property Level Authorization (BOPLA)

APIs have become the primary mechanism through which enterprises expose data and functionality across applications, partners, and customers. As API adoption accelerates, securing access becomes more complex. It is no longer enough to control who can call an API. Teams must also control which data fields can be viewed or modified within API responses and requests.

Industry research consistently shows that access control failures and excessive data exposure increase breach impact and recovery effort. The IBM Cost of a Data Breach Report highlights that breaches involving sensitive data exposure and inadequate access controls create significant financial and regulatory consequences. When APIs return more data than intended or allow unauthorized modification of sensitive fields, exposure can include personally identifiable information, financial attributes, or security critical flags. This increases compliance risk and damages customer trust.

From the development and platform perspective, managing authorization at scale is a persistent challenge. The Postman State of the API Report shows that API producers continue to prioritize security concerns tied to unauthorized use, excessive access, and protecting credentials. These concerns become harder to address as APIs evolve quickly, serve multiple consumer types, and accumulate schema complexity over time.

Security analysts have also emphasized that modern API risk often shifts from endpoints to data structures. Many teams focus on protecting routes and methods, but vulnerabilities increasingly appear in the properties inside returned objects or accepted payloads. This aligns with OWASP’s inclusion of Broken Object Property Level Authorization as a key API security risk, reflecting the prevalence of excessive data exposure and mass assignment patterns in real systems.

Broken object property level authorization enables attackers to read or manipulate specific fields within objects that the user is otherwise allowed to access. These flaws are often introduced during normal API evolution, such as adding new fields, expanding responses, or reusing request models across endpoints. They are subtle, difficult to detect with perimeter controls, and costly when exploited.

As enterprises expose richer APIs and rely more on automated clients, mobile applications, and third party integrations, BOPLA vulnerabilities pose a growing risk to privacy, compliance, and business integrity. Preventing them requires deliberate design, consistent enforcement, and continuous validation of object property access controls.

What is Broken Object Property Level Authorization (BOPLA)

Broken Object Property Level Authorization, commonly referred to as BOPLA, is an API security vulnerability where an application fails to properly restrict access to specific properties or fields within an object. While a user may be authorized to access an object as a whole, the API does not adequately control which individual attributes of that object the user is permitted to read or modify.

OWASP defines BOPLA as a condition that leads to excessive data exposure or unauthorized property modification. This occurs when APIs return sensitive fields that the client should not see or accept input for properties that the client should not be allowed to change. Unlike object level authorization issues, which focus on access to entire resources, BOPLA operates at a finer level of granularity inside the object itself.

In practical terms, a BOPLA vulnerability arises when an API trusts client supplied input or response models too broadly. For example, an API may correctly authorize a user to retrieve their own account record but unintentionally include internal attributes such as account status, privilege flags, risk scores, or administrative metadata in the response. Similarly, during update operations, the API may allow the client to submit properties that should be system managed only, such as role assignments or verification indicators.

BOPLA is closely associated with two common API design flaws. The first is excessive data exposure, where APIs return complete object representations instead of minimal, purpose specific views. The second is mass assignment, where APIs automatically bind request payloads to backend data models without validating which properties are safe to update.

These vulnerabilities are especially prevalent in modern API architectures that rely on shared schemas, reusable data transfer objects, and rapid iteration. As APIs evolve, new properties are added to objects to support additional features, but authorization rules at the property level are not always revisited or enforced consistently.

Because BOPLA vulnerabilities involve legitimate endpoints, valid credentials, and structurally correct requests, they are difficult to detect through traditional perimeter controls. The requests do not appear malicious in isolation and often blend into normal API traffic. As a result, broken object property level authorization represents a high risk but frequently overlooked category of API security issues.

Understanding BOPLA is essential for securing APIs that expose sensitive data or support write operations on complex objects. Preventing it requires deliberate control over which properties are exposed, which fields are writable, and how authorization decisions are enforced at the property level for every API operation.

Why is Object Property Level Authorization Important in Security

Object property level authorization is essential for maintaining data privacy, preserving business logic integrity, and reducing regulatory and reputational risk. It ensures that APIs expose only what is necessary, accept only what is intended, and enforce authorization at the level where modern API breaches most often occur.

1. Prevents Excessive Data Exposure in Modern APIs

Object property level authorization is critical because modern APIs rarely expose single purpose data. Most APIs return complex objects that contain a mix of public, sensitive, derived, and system managed fields. Securing access to the object alone is not sufficient if individual properties within that object are not equally protected.

2. Enforces Fine Grained Authorization Beyond Identity

Authentication confirms identity, and authorization defines which resources a user can access. Object property level authorization extends this by enforcing which specific fields within a resource can be viewed or modified. Without this control, APIs risk exposing sensitive information or allowing unintended changes even when object access itself is legitimate.

3. Supports Multiple API Consumers Safely

APIs are designed to be reused across different consumers. A mobile application, a partner integration, and an internal service may all call the same endpoint but require access to different subsets of data. Without property level authorization, APIs often return the same full object to every consumer, significantly increasing the risk of excessive data exposure.

4. Protects Confidential and System Managed Fields

Many APIs store sensitive attributes such as internal identifiers, security flags, verification states, or risk indicators alongside user facing fields. Exposing these properties can reveal internal system logic, enable targeted abuse, or create compliance violations even when no unauthorized object access occurs.

5. Preserves Data Integrity and Business Logic

Property level controls are essential for preventing unauthorized modification of system managed fields. APIs that accept broad input payloads without validating which properties are writable may allow clients to manipulate attributes that should only be set by backend processes. This can result in privilege escalation, bypass of business rules, or corruption of critical data.

6. Prevents Authorization Drift as APIs Evolve

As APIs evolve, new fields are added to support features, analytics, or integrations. Authorization logic is not always updated at the same pace. Over time, this creates authorization drift where APIs unintentionally expose or accept properties that were never intended to be client accessible.

7. Addresses Gaps Left by Perimeter Security

Object property level authorization issues are difficult to detect using perimeter controls. Requests exploiting these weaknesses are authenticated, valid, and correctly formed. The risk lies in the data returned or accepted, not in request structure. Without explicit property level enforcement, these vulnerabilities remain invisible to traditional security defenses.

Examples of Broken Object Property Level Authorization (BOPLA)

Broken Object Property Level Authorization vulnerabilities occur when APIs correctly authorize access to an object but fail to control access to individual properties within that object. These flaws often go unnoticed because the API behaves as expected at a high level, while exposing or accepting data it should not.

The following examples illustrate common BOPLA patterns seen in modern APIs.

1. Excessive Data Exposure in API Responses

One of the most common BOPLA scenarios involves APIs returning more information than the client is authorized to see.

In this case, a user is legitimately allowed to retrieve their own account or profile data. However, the API responds with a complete object that includes internal or sensitive fields alongside user facing attributes. These fields may include internal status values, verification indicators, system flags, or risk related metadata that were never intended for client consumption.

The vulnerability arises because the API does not tailor its response based on the requester’s authorization level. Instead of returning only the necessary fields, it exposes the full object representation. While no unauthorized object access occurs, the excessive data exposure can reveal sensitive information, internal system behavior, or compliance sensitive attributes.

2. Mass Assignment Through Update Requests

Another common form of BOPLA occurs during write operations, particularly when APIs accept broad request payloads.

In this scenario, a user is allowed to update certain fields within an object, such as their display name or contact information. However, the API automatically binds all incoming properties to the backend data model without validating which fields are writable. As a result, the user can include additional properties in the request that should be system managed only.

This can allow unauthorized modification of fields such as role indicators, verification states, or privilege related attributes. The vulnerability exists because the API does not explicitly restrict which properties can be modified, trusting the client to send only permitted fields.

3. Inconsistent Property Authorization Across API Consumers

BOPLA vulnerabilities also appear when the same API endpoint serves multiple types of consumers.

For example, an API may be used by a mobile application, a partner integration, and internal services. Each consumer may require access to a different subset of object properties. If the API returns the same object structure to all consumers, sensitive fields intended only for internal use may be exposed externally.

This happens when property level authorization rules are not enforced per consumer context. Over time, as APIs are reused and extended, these inconsistencies can lead to widespread excessive data exposure without any change to endpoint level access controls.

4. Authorization Drift as APIs Evolve

APIs evolve continuously, and BOPLA vulnerabilities are often introduced unintentionally during this process.

New properties may be added to objects to support features, analytics, or operational workflows. If authorization rules are not updated alongside these changes, the new fields may become readable or writable by default. This creates authorization drift, where APIs gradually expose properties that were never reviewed from a security perspective.

Because these changes are incremental and do not affect endpoint access, the resulting vulnerabilities are difficult to spot without deliberate property level authorization review.

Risks and Impact of BOPLA

Broken Object Property Level Authorization introduces significant security and business risk because it exposes or allows manipulation of sensitive data within otherwise authorized objects. Unlike broader authorization failures, BOPLA vulnerabilities often remain unnoticed since the API appears to function correctly and access to the resource itself is legitimate.

Excessive Exposure of Sensitive Data

One of the most direct impacts of BOPLA is excessive data exposure. APIs may unintentionally return internal or sensitive properties such as security flags, verification states, internal identifiers, or operational metadata alongside user facing fields. Even when users are entitled to access the object, exposure of these properties can violate privacy requirements, reveal internal system behavior, or provide attackers with information that enables further abuse.

This type of exposure is especially damaging because it often involves structured and high quality data rather than random leakage. Once discovered, it can be harvested at scale without triggering obvious security alerts.

Unauthorized Modification of Critical Properties

BOPLA vulnerabilities also affect data integrity. When APIs fail to restrict which properties are writable, attackers can manipulate fields that should only be controlled by backend processes. This may include privilege indicators, approval states, or security related attributes.

Such modifications can lead to privilege escalation, bypass of business rules, or corruption of application state. Because the API accepts valid requests and processes them normally, these changes may persist undetected until secondary effects appear.

Increased Regulatory and Compliance Risk

APIs that expose or accept unauthorized properties often handle regulated data such as personal information, financial attributes, or identity related fields. Excessive exposure or unintended modification of these properties increases regulatory risk and complicates compliance with data protection requirements.

Even if no full account compromise occurs, disclosure of sensitive fields can constitute a reportable incident, increasing legal and reputational impact.

Why Most WAFs Cannot Detect or Block BOPLA

Like BOLA, BOPLA exploits are extremely difficult for traditional WAFs to detect or block. WAFs are designed to identify malformed requests, known attack patterns, or protocol violations. In a BOPLA exploit, none of these signals are present.

The request is authenticated, the endpoint is valid, and the payload conforms to the expected schema. The issue lies in which properties are included in the response or accepted in the request, and whether the requester is authorized to access or modify them.

WAFs do not understand business context, data sensitivity, or property level authorization rules. From the WAF’s perspective, the traffic is indistinguishable from legitimate API usage. As a result, BOPLA vulnerabilities routinely bypass perimeter defenses and remain exploitable in production environments.

Difficulty of Detection and Delayed Discovery

BOPLA vulnerabilities are often discovered late because their effects are subtle. APIs do not fail, error rates do not spike, and logs show valid access patterns. In many cases, organizations become aware of the issue only after sensitive data is observed externally or misuse leads to downstream anomalies.

This delayed discovery increases the scope of exposure and makes incident response more complex.

Business and Trust Impact

Ultimately, the impact of BOPLA extends beyond technical risk. Exposure or manipulation of sensitive object properties undermines trust in API driven systems. Customers and partners expect APIs to enforce strict data boundaries, even at the field level. When those boundaries fail, confidence in the platform erodes.

For these reasons, broken object property level authorization represents a high impact API security risk. It exploits legitimate behavior, evades traditional defenses, and directly affects data confidentiality, integrity, and compliance.

Why does a BOPLA vulnerability occur?

Broken Object Property Level Authorization vulnerabilities occur when APIs do not consistently enforce authorization at the level of individual fields within an object. While the root cause appears simple, these flaws typically arise from a combination of design decisions, development practices, and operational assumptions common in modern API environments.

1. Overexposure of Object Models

One of the most common causes of BOPLA is the direct exposure of backend object models through APIs. When APIs return or accept complete object representations by default, all properties become accessible unless explicitly restricted. This approach increases the likelihood that sensitive or internal fields are unintentionally exposed or made writable.

Without deliberate control over which properties are included in responses or accepted in requests, APIs inherit the full complexity of internal data models and their associated risks.

2. Reuse of Shared Schemas Across Endpoints

APIs often rely on shared schemas or data transfer objects to improve development efficiency. While this reduces duplication, it also increases the risk of BOPLA when the same schema is reused across endpoints with different authorization requirements.

A schema designed for internal services may include properties that should not be visible or modifiable by external clients. If property level authorization is not enforced per use case, these fields become accessible through endpoints that were never intended to expose them.

3. Mass Assignment and Automatic Binding

BOPLA vulnerabilities frequently arise during write operations when APIs automatically bind incoming request payloads to backend objects. This pattern assumes that clients will only send permitted fields. In practice, attackers can include additional properties in the request, and the API may persist them without validation.

This behavior enables unauthorized modification of system managed fields and is a common source of mass assignment vulnerabilities in APIs.

4. Incomplete Authorization Design

Authorization is often implemented at the endpoint or object level, with property level controls treated as an afterthought. Developers may assume that restricting access to the object is sufficient, without considering that different properties within the object may require different access rules.

As a result, APIs enforce coarse authorization while leaving finer grained property access unchecked.

5. Authorization Drift During API Evolution

APIs evolve continuously. New fields are added to support features, analytics, or operational needs. When authorization logic is not revisited alongside these changes, newly added properties may become accessible by default.

Over time, this creates authorization drift, where the API’s effective access controls no longer match its intended security model.

6. Lack of Property Focus in Testing

Traditional API testing often emphasizes functional correctness and endpoint level access control. Property level authorization scenarios are more complex to test and are frequently omitted from test coverage.

Without explicit testing of which fields are returned or writable for different users and contexts, BOPLA vulnerabilities can persist unnoticed into production.

7. Reliance on Perimeter Controls

Some teams assume that perimeter defenses will mitigate data exposure risks. However, BOPLA vulnerabilities do not involve malformed requests or suspicious traffic patterns. Requests are valid, authenticated, and correctly structured. Without enforcement inside the API, these flaws remain invisible to external controls.

How to Identify BOPLA Vulnerabilities

Identifying Broken Object Property Level Authorization vulnerabilities requires focusing on what data is exposed or accepted, not just whether access to an API endpoint is permitted. Because BOPLA exploits legitimate object access, detection depends on examining responses, request payloads, and authorization behavior at the property level.

1. Review API Responses for Excessive Data Exposure

A primary indicator of BOPLA is the presence of fields in API responses that the client does not need or should not see.

To identify this issue:

• Inspect response payloads for internal, sensitive, or system managed properties
• Compare returned fields against the intended use case of the endpoint
• Validate that different user roles or consumer types receive appropriately filtered responses

If all consumers receive the same full object regardless of context, property level authorization is likely missing.

2. Test Property Access Across User Roles and Contexts

BOPLA often manifests when different users or applications access the same object but should have different visibility or modification rights.

Testing should include:

• Comparing responses for the same object across different user roles
• Verifying that privileged fields are not visible to lower privilege users
• Confirming that internal attributes are not exposed to external consumers

Any inconsistency between expected and actual field visibility may indicate a BOPLA vulnerability.

3. Manipulate Request Payloads During Write Operations

For update and create operations, BOPLA vulnerabilities can be identified by submitting additional properties in request payloads.

This involves:

• Sending fields that are not documented or intended to be client writable
• Modifying properties that should be system managed only
• Observing whether the API accepts and persists these changes

If the API processes unexpected properties without validation, it is vulnerable to mass assignment related BOPLA issues.

4. Validate Read and Write Controls Separately

An API may correctly restrict which fields can be viewed but fail to restrict which fields can be modified, or vice versa.

Identification efforts should verify:

• That sensitive properties are not included in read responses
• That restricted properties cannot be updated through write operations
• That partial updates enforce the same property rules as full updates

Inconsistent enforcement across operations is a common source of BOPLA.

5. Assess API Behavior as Schemas Evolve

BOPLA vulnerabilities are frequently introduced when new fields are added to existing objects.

To detect this:

• Review recently added properties for unintended exposure
• Confirm that new fields inherit appropriate authorization rules
• Test backward compatibility paths where older clients may receive expanded responses

Schema changes without corresponding authorization review are a high risk indicator.

6. Examine Error Handling and Silent Failures

In some cases, APIs may accept unauthorized property changes without obvious errors, making detection harder.

Identification should include:

• Verifying the persisted state of objects after update requests
• Checking logs or follow up reads to confirm whether restricted fields were modified
• Ensuring that unauthorized property access produces consistent and explicit denial behavior

Silent acceptance of unauthorized fields is a strong signal of BOPLA.

Why Identifying BOPLA Is Challenging

BOPLA vulnerabilities are difficult to identify because the API behaves correctly at a high level. Requests succeed, responses are valid, and no obvious security alerts are triggered. The flaw exists in the granularity of authorization, not in endpoint access.

This is why identifying BOPLA requires deliberate property level testing and ongoing review as APIs evolve, rather than reliance on automated scanning or perimeter defenses alone.

Difference between Broken Object Property Level Authorization and Broken Object Level Authorization (BOPLA vs BOLA)

Broken Object Level Authorization determines whether a user should access a resource at all, while Broken Object Property Level Authorization determines what data within that resource should be exposed or modifiable. An API can be fully protected against BOLA and still be vulnerable to BOPLA if property level controls are not enforced.

In practice, many real-world API breaches involve both vulnerabilities simultaneously, which is why effective API security programs must address authorization at both the object and property levels.

How to Monitor and Detect BOPLA Exploits in Runtime

Monitoring and detecting Broken Object Property Level Authorization exploits in runtime is inherently challenging because these attacks rely on valid API behavior. Requests are authenticated, endpoints are correct, and payloads conform to expected schemas. The abuse occurs at the data level, where unauthorized properties are exposed or modified without triggering traditional security signals.

1. Monitor Response Payloads for Excessive Data Exposure

Runtime detection of BOPLA begins with observing what data APIs actually return in production. Monitoring systems should analyze response payloads to identify properties that exceed what is required for the API’s intended use.

Key signals include:

• Presence of internal or system managed fields in external responses
• Responses that consistently return full object representations instead of filtered views
• Sudden appearance of new properties in responses after schema changes
• Unexpected data exposure is often the earliest indicator of a BOPLA issue.

2. Track Unauthorized Property Modification Attempts

BOPLA exploits frequently involve write operations where clients submit additional or restricted fields in request payloads.

Runtime monitoring should look for:

• Requests that include properties not typically sent by legitimate clients
• Attempts to modify fields that are normally stable or backend controlled
• Changes to sensitive attributes that do not align with expected workflows
• These patterns often indicate mass assignment or insufficient property validation.

3. Correlate Property Access with Identity and Context

Detecting BOPLA requires understanding who is accessing which fields and why. Runtime systems must correlate property access with user identity, role, tenant, and consumer type.

Indicators of exploitation include:

• Lower privilege users accessing fields typically used by administrators
• External consumers receiving internal only attributes
• Property access patterns that deviate from established usage baselines

Without this contextual correlation, BOPLA activity blends into normal traffic.

4. Monitor Schema Changes and Authorization Drift

BOPLA vulnerabilities are often introduced during API evolution. Runtime monitoring should flag when new properties begin appearing in responses or requests without corresponding authorization controls.

Effective detection includes:

• Observing changes in payload structure over time
• Identifying newly writable fields that were previously read only
• Detecting inconsistencies between API versions handling the same object

These signals help identify authorization drift before it leads to widespread exposure.

5. Analyze Patterns Rather Than Single Requests

Single BOPLA requests often appear benign. Detection improves when behavior is analyzed across multiple interactions.

Patterns to monitor include:

• Repeated access to sensitive properties across many objects
• Systematic inclusion of additional fields in update requests
• Gradual expansion of property usage beyond typical client behavior

Pattern based analysis helps distinguish exploitation from normal usage.

Why Traditional Runtime Controls Fall Short

Most perimeter defenses focus on request structure, known attack signatures, or protocol violations. In BOPLA exploits, none of these indicators are present. The requests are valid, authenticated, and aligned with documented endpoints.

Because WAFs and similar controls lack visibility into data sensitivity and property level authorization rules, they cannot reliably detect or block BOPLA exploits. The risk lies in what data is returned or modified, not in how the request is formed.

Limits of Runtime Detection Alone

While runtime monitoring can help identify ongoing exploitation, it is reactive by nature. By the time a BOPLA exploit is detected, sensitive data may already have been exposed or modified.

This is why effective BOPLA mitigation requires a combination of runtime detection, preventive design, and continuous authorization testing throughout the API lifecycle.

Strategies & Best Practices for preventing BOPLA attacks

Broken Object Property Level Authorization vulnerabilities are fundamentally design and implementation flaws, not traffic level anomalies. They arise when APIs are built without explicit rules governing which properties can be exposed or modified by different consumers. As a result, attempting to block BOPLA attacks only in production is ineffective. Prevention must start earlier in the API lifecycle through shift left security practices.

1. Treat Property Authorization as a Design Requirement

Preventing BOPLA begins at API design time. Every API response and request payload should be evaluated not just for functionality, but for data necessity.

Best practices include:

• Explicitly defining which properties are readable and writable per role or consumer
• Avoiding default full object serialization in responses
• Separating public facing fields from internal or system managed attributes

Property level authorization must be intentional. If it is left implicit, it will almost always be incomplete.

2. Continuously Discover APIs and Data Exposure Paths

BOPLA risks increase as APIs evolve. New fields are added for features, analytics, or internal processing, but authorization logic often remains unchanged.

Continuous API discovery helps teams:

• Identify APIs exposing complex objects with sensitive attributes
• Detect undocumented or legacy endpoints returning full object payloads
• Maintain visibility into how data structures change over time

Without accurate visibility into the API surface and exposed properties, enforcing consistent authorization becomes impossible.

3. Shift Left with Continuous Authorization Testing

Property level authorization cannot be validated through simple functional testing. It requires security focused testing that evaluates how APIs behave when presented with unexpected or excessive data access scenarios.

Shift left testing strategies should include:

• Testing for excessive data exposure in API responses
• Validating that sensitive fields are excluded for unauthorized consumers
• Attempting modification of system managed or restricted properties
• Verifying behavior across roles, tenants, and API versions

Detecting these issues before deployment is significantly more effective than attempting to detect abuse after data has already been exposed.

4. Prioritize Property Controls on Sensitive Endpoints

Not all APIs carry the same risk. BOPLA prevention efforts should focus first on endpoints that:

• Handle personal, financial, or regulated data
• Return large or nested objects
• Support update or bulk operations
• Serve multiple types of consumers such as mobile apps, partners, and internal services

Applying stricter property level authorization to high risk endpoints reduces the likelihood of large scale exposure.

5. Avoid Over Reliance on Production Defenses

Production controls such as WAFs and API gateways are not designed to understand business level data sensitivity. BOPLA attacks use valid credentials, valid endpoints, and valid request structures. The vulnerability lies in what data is returned or accepted, not in how the request is formed.

This makes BOPLA particularly resistant to perimeter based protection. Preventing it requires building correct authorization logic into the API itself rather than relying on runtime traffic inspection.

6. Use Runtime Monitoring as a Safety Net, Not the Primary Control

Runtime monitoring remains important for detecting unexpected data access patterns, authorization drift, and abuse scenarios that slip through testing. However, it should complement, not replace, preventive controls.

Effective BOPLA prevention combines:

• Secure by design API models
• Continuous discovery and documentation
• Shift left authorization testing
• Runtime monitoring for validation and response

Why Shift Left Matters for BOPLA

BOPLA vulnerabilities are cheapest to fix when identified early and most expensive when discovered in production. Once exposed, sensitive properties may already be cached, logged, or consumed by downstream systems.

By shifting authorization enforcement and validation earlier in the API lifecycle, enterprises reduce breach impact, lower remediation costs, and prevent silent data exposure that is difficult to detect after the fact.

In summary, preventing BOPLA attacks requires treating property level authorization as a first class security concern. Continuous discovery, continuous testing, and prioritization of sensitive data paths are essential. Runtime defenses alone cannot compensate for authorization gaps that originate in API design.

How Levo prevents BOPLA attacks

Preventing Broken Object Property Level Authorization requires more than endpoint level controls. BOPLA vulnerabilities emerge when APIs expose or accept properties without validating whether the caller is authorized to view or modify those specific fields. Levo addresses this challenge by automating authorization testing at the data property level, where traditional tools and manual reviews fall short.

1. Automated Discovery of Object Properties and Data Exposure

Levo continuously analyzes APIs to understand the full structure of request and response payloads. This includes identifying all object properties exposed by an API, including nested and derived fields that are often overlooked during development.

By building an accurate view of object schemas as they exist in practice, not just as documented, Levo helps security teams detect excessive data exposure and hidden property level risks early in the lifecycle.

2. Property Level Authorization Validation

Levo automatically tests whether APIs enforce correct authorization rules for individual properties. Instead of assuming that object level access implies full data access, Levo evaluates whether sensitive or system managed fields are appropriately restricted based on identity, role, tenant, and context.

This enables teams to identify:

• Properties that are returned to unauthorized consumers
• Fields that should be read only but are writable
• Attributes that are accepted silently through mass assignment

These tests surface BOPLA vulnerabilities before they reach production, when remediation is fastest and least disruptive.

3. Continuous Testing Across API Changes

BOPLA vulnerabilities frequently appear when APIs evolve. New fields are added, schemas are reused, and authorization logic is not updated accordingly. Levo continuously revalidates property level access controls as APIs change, preventing authorization drift over time.

This ensures that newly introduced properties do not become exposed or writable by default and that security posture remains aligned with intended access policies.

4. Context Aware Authorization Testing

Levo evaluates authorization behavior across different user roles, consumer types, and access scenarios. This allows teams to confirm that APIs return only the appropriate subset of properties for each context, rather than relying on one size fits all responses.

By testing how the same object behaves under different identities and permissions, Levo reveals subtle BOPLA issues that are invisible in single role testing.

5. Shift Left Prevention by Design

Because BOPLA is a design level flaw, preventing it requires early feedback during development and testing. Levo integrates authorization validation into the API lifecycle, enabling teams to detect property level authorization gaps before deployment.

This shift left approach reduces reliance on reactive production controls and helps organizations enforce secure by design API principles at scale.

Why This Matters for Enterprises

BOPLA vulnerabilities expose sensitive data without triggering obvious failures or alerts. Once deployed, these flaws are difficult to detect and expensive to remediate. By automating property level authorization testing, Levo enables enterprises to systematically prevent one of the most subtle and damaging classes of API security vulnerabilities.

In doing so, Levo helps organizations ensure that APIs expose only what is necessary, accept only what is intended, and enforce authorization at the level where modern API breaches most often occur.

How Levo detects and block BOPLA attacks in runtime 

Broken Object Property Level Authorization attacks are difficult to stop in production because they exploit valid object access paths while abusing data exposure or modification at the property level. Requests are authenticated, endpoints are correct, and payloads follow expected schemas. The violation exists only in whether the caller is authorized to see or change specific fields. Addressing this requires runtime security that understands data sensitivity, authorization intent, and behavioral context, not just traffic patterns.

1. Runtime Detection of Unauthorized Property Access

Levo detects BOPLA exploits by observing API behavior directly where execution occurs and correlating property access with identity and context. This allows Levo to identify when APIs expose or accept properties that fall outside expected authorization boundaries.

At runtime, Levo evaluates:

• Which properties are returned in responses and to whom
• Which fields are modified during write operations
• How property access aligns with role, tenant, and consumer context

This makes it possible to detect excessive data exposure and unauthorized field modification even when requests are structurally valid and authenticated.

2. Behavioral Detection Instead of Signature Matching

BOPLA exploitation does not rely on malformed input or known attack signatures. It relies on normal looking requests that abuse missing property checks. Traditional WAFs and API gateways are blind to this because they do not track which fields should be visible or writable in a given context.

Levo uses behavior aware detection to identify deviations such as:

• Sensitive properties appearing in responses where they were previously absent
• Stable system managed fields being modified unexpectedly
• New properties becoming writable after schema changes

Because detection is tied to real API behavior rather than static rules, Levo can surface BOPLA exploitation without generating noise or false positives.

3. Continuous Coverage Across All APIs

BOPLA vulnerabilities frequently exist in APIs that security teams are unaware of, including internal services, partner integrations, and older versions. Levo continuously discovers and monitors APIs at runtime, ensuring that property-level behavior is observed everywhere it occurs.

This eliminates blind spots where excessive data exposure or mass assignment issues typically persist unnoticed and ensures detection applies consistently across the entire API estate.

4. Precision Blocking Without Breaking Applications

Blocking BOPLA attacks in production is risky when done without context. Overly aggressive controls can disrupt legitimate users and workflows. Levo avoids this by enforcing authorization-aware protection.

When a BOPLA exploit is detected, Levo can:

• Block the specific request attempting unauthorized property access
• Scope enforcement to the affected endpoint, service, or environment
• Apply stricter controls only where sensitive data is involved

Because enforcement decisions are based on property-level context and observed behavior, blocking is precise and does not degrade application performance or user experience.

5. Explainable Enforcement and Rapid Remediation

Every detection and block performed by Levo is explainable. Security and engineering teams can see:

• Which property triggered the violation
• Which API and service were involved
• Why the access was considered unauthorized

This clarity enables teams to trace runtime incidents back to the underlying authorization gap and remediate the root cause quickly, rather than relying on long term compensating controls.

Why Levo Is Uniquely Capable of Runtime BOPLA Protection

Detecting and blocking BOPLA attacks requires capabilities that traditional tools do not have:

• Visibility into encrypted API traffic and internal service calls
• Awareness of data sensitivity and property usage
• Correlation of identity, object, and property access in real time
• Enforcement that is precise enough to avoid false positives

By combining these elements, Levo closes a critical gap in API security. It enables enterprises to detect and block property-level authorization abuse as it happens, while feeding those insights back into testing and design processes to prevent recurrence.

The way ahead: Implementing API Security to prevent BOPLA

Preventing Broken Object Property Level Authorization requires more than isolated fixes. BOPLA vulnerabilities emerge from how APIs are designed, evolved, and operated. Enterprises must adopt a comprehensive API security approach that spans visibility, classification, testing, monitoring, detection, and protection, with consistent governance across the API lifecycle.

Levo enables this end-to-end model by unifying multiple API security capabilities into a single platform, allowing organizations to prevent BOPLA and related authorization risks systematically rather than reactively.

1. Establish Complete API Visibility and Ownership

Effective prevention begins with knowing what APIs exist and how they behave. Enterprises often underestimate the number of APIs they expose, including internal services, partner integrations, legacy versions, and undocumented endpoints.

Levo provides continuous API inventory and documentation, ensuring that all APIs and their request and response structures are visible and understood. This visibility is critical for identifying where complex objects are exposed and where property-level authorization controls are required.

Without accurate inventory and up-to-date documentation, BOPLA vulnerabilities remain hidden and unaddressed.

2. Identify and Prioritize Sensitive Data Exposure

Not all APIs carry the same risk. BOPLA impact is highest when sensitive or regulated data is involved.

Levo enables sensitive data discovery across API payloads, helping enterprises understand which object properties contain personal, financial, identity-related, or security-critical information. This allows teams to prioritize property-level authorization controls on APIs that matter most, rather than applying uniform controls that may miss high-risk paths.

By aligning authorization enforcement with data sensitivity, organizations reduce exposure and compliance risk.

3. Prevent BOPLA Through Shift-Left Security Testing

Because BOPLA is a design flaw, it is most effectively addressed before APIs reach production.

Levo integrates API security testing into the development lifecycle, enabling continuous validation of authorization behavior at the property level. This includes testing for excessive data exposure, unauthorized field modification, and mass assignment risks across roles, tenants, and consumer contexts.

By catching property-level authorization gaps early, enterprises reduce reliance on production controls and avoid costly remediation after sensitive data has already been exposed.

4. Maintain Continuous Monitoring and Validation

APIs evolve continuously, and authorization drift is a common source of BOPLA vulnerabilities.

Levo provides ongoing API monitoring and vulnerability reporting to track changes in payload structure, newly exposed properties, and authorization behavior over time. This continuous validation ensures that new fields introduced during development do not become accessible or writable by default.

Monitoring also helps teams detect deviations from intended authorization models before they escalate into incidents.

5. Detect and Block BOPLA Exploits in Runtime

Even with strong preventive controls, runtime protection remains essential.

Levo’s API detection and API protection capabilities enable enterprises to identify and block BOPLA exploitation in production by observing real API behavior and enforcing authorization-aware controls. Unlike traditional perimeter defenses, these controls operate with awareness of data sensitivity and property access context.

This ensures that unauthorized exposure or modification of object properties can be stopped in real time without disrupting legitimate API usage.

6. Operationalize API Security at Enterprise Scale

Preventing BOPLA consistently across large API estates requires security to be operational, programmable, and auditable.

Levo supports this through centralized vulnerability reporting and governed automation capabilities, enabling teams to integrate API security into DevSecOps workflows, remediation processes, and ongoing governance. Security insights can be acted upon consistently across development, security, and operations teams.

This operational foundation ensures that BOPLA prevention is not a one-time effort, but a sustained security posture.

A Unified Approach to Preventing BOPLA and Beyond

Broken Object Property Level Authorization is one manifestation of a broader challenge. APIs expose increasingly rich data structures, and authorization must evolve accordingly.

By combining API inventory, documentation, sensitive data discovery, security testing, monitoring, detection, and protection in a single platform, Levo enables enterprises to prevent BOPLA and a wide range of API security risks. This unified approach ensures that APIs expose only what is necessary, accept only what is intended, and enforce authorization at the level where modern API breaches most often occur.