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Recurring Security Weaknesses in AI-Assisted Applications: Observations from Penetration Testing

AI-assisted development speeds up software delivery but can amplify common security weaknesses. This article explores five vulnerabilities frequently identified during penetration testing and practical ways to reduce the risk.

Recurring Security Weaknesses in AI-Assisted Applications: Observations from Penetration Testing

AI-assisted development has rapidly become part of modern software engineering. Development teams now rely on AI coding assistants to generate application logic, build APIs, write tests, and accelerate routine implementation tasks.

While these tools deliver measurable productivity gains, they also change how software is produced and, consequently, how security weaknesses emerge.

From an application security perspective, AI is not creating fundamentally new classes of vulnerabilities. Instead, it is increasing the likelihood that familiar security flaws are introduced when generated code is integrated without sufficient architectural review, security validation, or an understanding of the application's broader context.

Across penetration tests of SaaS platforms, APIs, and enterprise applications, the most significant findings rarely originate from isolated coding errors. They are more often rooted in weaknesses within:

  • Authorization models
  • Trust boundaries
  • Secret management
  • Input validation
  • Interactions between interconnected components

AI-generated code may be technically correct, but it has no inherent understanding of an organization's business logic, security architecture, or threat model.

The observations presented in this article are drawn from recurring patterns identified by Redseclabs researchers and penetration testers during security assessments of AI-assisted applications. 

Key Takeaways

  • AI-assisted development increases productivity but does not replace secure software design.
  • Most vulnerabilities found in AI-assisted applications are well-established security issues rather than AI-specific flaws.
  • Authorization logic, secret management, input validation, and API design continue to account for many critical findings.
  • Security weaknesses often emerge where generated code interacts with existing business logic, cloud infrastructure, or third-party services.
  • Architecture reviews, secure code review, and penetration testing remain essential before deploying AI-assisted applications into production.

1. Broken Access Control and Authorization Logic

Broken access control remains one of the most common and most impactful findings during penetration tests of AI-assisted applications. 

Simply put, “broken access control means an application fails to properly enforce what an authenticated user is allowed to access or perform.” 

A user may successfully log in, but the application does not consistently verify whether they are authorized to perform a requested action.

While authentication is usually implemented correctly, authorization logic is often inconsistent across the application. This is particularly common in applications where AI-generated code is used to accelerate API development. 

Generated CRUD endpoints often validate that a request originates from an authenticated user but assume that object identifiers, tenant IDs, or resource references supplied by the client are legitimate. 

If those assumptions are not verified on the server, attackers can access or manipulate resources belonging to other users.

Common Examples

Type

Example

IDOR (Insecure Direct Object Reference)

Changing /api/orders/1001 to /api/orders/1002 returns another user's order because ownership is never verified.

Horizontal Privilege Escalation

A user modifies an identifier to access another user's account with the same privilege level.

Vertical Privilege Escalation

A standard user directly accesses an administrator endpoint that lacks authorization checks.

Client-side Only Checks

The UI hides admin functions, but the backend API still accepts unauthorized requests.

A few years back, security researchers discovered that Microsoft Power Apps portals had exposed approximately 38 million records from organizations including American Airlines, Ford, and several U.S. government agencies. The issue was caused by misconfigured access permissions that unintentionally made backend data publicly accessible through APIs.

Although the vulnerability was not caused by AI-generated code, it demonstrates how a single authorization oversight can expose large volumes of sensitive information when access controls are not consistently enforced. 

Why Attackers Target It

Authorization flaws are attractive because they often require little technical sophistication. Instead of exploiting software vulnerabilities, attackers simply manipulate object identifiers, tenant IDs, or API parameters that the application already accepts. 

These weaknesses align closely with OWASP Top 10: Broken Access Control and OWASP API Security Top 10: Broken Object Level Authorization (BOLA). Successful exploitation can expose customer records, financial information, administrative functionality, or data belonging to other tenants.

How To Detect It

Security testers typically identify broken access control by:

  • Modifying object IDs or tenant IDs in requests.
  • Accessing another user's resources while authenticated.
  • Calling administrative endpoints as a standard user.
  • Bypassing client-side restrictions and testing APIs directly.
  • Verifying that every server-side request performs authorization checks.

How To Reduce The Risk

  • Enforce authorization on every server-side request.
  • Verify ownership before every read, update, or delete operation.
  • Centralized authorization policies instead of embedding checks throughout the application.
  • Test every API endpoint independently during code reviews and penetration testing.
  • Never rely on client-side validation or hidden interface elements for security.

AI can generate functional endpoints in seconds, but it cannot determine who should have access to a resource or how an organization's authorization model should be enforced. Those decisions remain the responsibility of developers, architects, and security reviewers.

2. Exposed Secrets and Insecure Credential Management

Exposed credentials remain one of the easiest ways for attackers to gain access to an application environment. 

Across AI-assisted applications, exposed API keys, database credentials, cloud access tokens, and service account secrets continue to appear during security assessments. This is not because AI-generated code is inherently insecure, but because development often prioritizes speed over secure credential management.

AI-generated code frequently includes sample configuration files, placeholder API keys, hardcoded connection strings, or authentication tokens to help developers get an application running quickly. While suitable for demonstrations, these examples become a security risk when copied into production without proper secret management. 

As projects evolve, the same credentials may also be reused across repositories, CI/CD pipelines, container images, and deployment templates, increasing the likelihood of accidental exposure.

Toyota disclosed that a cloud configuration containing authentication credentials had been accidentally stored in a public GitHub repository, exposing customer information for approximately 2.15 million users over several years. 

The incident highlights how hardcoded secrets and poor credential management can remain unnoticed for long periods, reinforcing the importance of secret scanning, credential rotation, and centralized secret management. 

Why Attackers Target It

Unlike many application vulnerabilities, exposed credentials often eliminate the need for exploitation altogether. A valid cloud access key, database password, or API token can provide immediate access to infrastructure, storage services, internal APIs, or administrative functionality. 

This remains a widespread industry problem, with reports such as GitGuardian's State of Secrets Sprawl consistently identifying millions of exposed secrets in public repositories. 

How To Reduce The Risk

Effective secret management begins with the assumption that application code should never contain sensitive credentials.

Development teams should:

  • Store secrets in dedicated secret management platforms such as cloud-native vaults or enterprise secret stores.
  • Remove API keys, passwords, and tokens from source code, frontend assets, and configuration files before deployment.
  • Enable automated secret scanning within source repositories and CI/CD pipelines to identify accidental exposures early.
  • Rotate credentials immediately whenever exposure is suspected, regardless of whether abuse has been confirmed.
  • Apply least-privilege permissions to every credential so that compromise has limited operational impact.
  • Review AI-generated configuration files and deployment templates before promoting them to production.

3. Insufficient Input Validation and Trust Boundary Assumptions

Input validation remains another fundamental security control in application development, yet it is also one of the most inconsistently implemented. During assessments of AI-assisted applications, APIs often validate data only for expected functionality while implicitly trusting requests from frontend applications, internal services, or other systems.

This rarely means validation is completely absent. More commonly, validation is inconsistent across the application

One endpoint rejects malformed input, while another processing the same data performs only minimal validation. As AI-generated components are added independently, these inconsistencies become increasingly difficult to identify.

AI-generated code typically focuses on producing functional endpoints, not enforcing organizational trust boundaries. As a result, developers may inherit validation logic that works during normal operation but fails when requests are intentionally manipulated.

Why Attackers Target It

Attackers look for endpoints that apply weaker validation than the rest of the application. By submitting unexpected values, oversized payloads, modified identifiers, or malformed requests, they can manipulate application behavior without exploiting a traditional software vulnerability. 

These weaknesses commonly align with OWASP Top 10 categories such as Injection, Security Misconfiguration, and Software and Data Integrity Failures.

How To Reduce The Risk

Development teams should:

  • Validate every untrusted input on the server, even when it has already been validated by the client.
  • Apply consistent validation rules across all APIs, services, and application components.
  • Use shared validation libraries or centralized schemas to reduce inconsistencies between services.
  • Reject unexpected parameters, unsupported formats, and values that fall outside defined business rules.
  • Include negative testing and malformed input testing as part of security assessments.
  • Review AI-generated validation logic to ensure it reflects the application's security requirements rather than only its functional requirements.

4. Excessive Data Exposure 

Modern applications are increasingly API-driven, making APIs one of the primary targets during penetration testing. Across AI-assisted applications, one of the most consistent findings is not an absence of security controls, but an excess of information returned by otherwise legitimate endpoints.

Generated APIs often prioritize convenience over data minimization. Frameworks expose complete model objects, serializers include every available attribute, and default responses return significantly more information than clients actually require. 

While this simplifies development, it also expands the application's attack surface by exposing internal details that were never intended to leave the server.

As applications evolve, this issue often becomes more pronounced. Data models change, new attributes are introduced, and APIs continue exposing entire objects simply because that is how they were initially generated. The result is an application that reveals considerably more about itself than necessary.

Why Attackers Target It

Attackers view excessive data exposure as a reconnaissance opportunity. Every unnecessary field returned by an API provides insight into the application's internal architecture.

Internal object identifiers may reveal predictable patterns that facilitate authorization attacks. Permission flags can expose administrative functionality. Email addresses, usernames, infrastructure references, and feature indicators often provide intelligence that supports credential attacks, privilege escalation, or further enumeration. Even when the exposed information is not immediately sensitive, it reduces the effort required to understand and map the application.

This is why the OWASP API Security Top 10 continues to identify Excessive Data Exposure as one of the most common API security risks. 

How To Reduce The Risk 

Reducing unnecessary data exposure begins with treating API responses as carefully as any other security control.

Development teams should:

  • Return only the fields required for each specific operation.
  • Use dedicated response models or Data Transfer Objects (DTOs) instead of exposing database entities directly.
  • Review API responses during code reviews to identify unnecessary attributes before deployment.
  • Test APIs specifically for information disclosure during penetration testing and security assessments.
  • Apply the principle of least privilege not only to user permissions but also to the data returned by every endpoint.
  • Maintain an inventory of externally accessible APIs and periodically review their responses as the application evolves.

AI coding assistants can generate functional APIs with remarkable speed, but they cannot determine which information should remain internal to an organization. 

Data minimization requires an understanding of business context, security architecture, and future risk, considerations that extend far beyond generating a working endpoint. 

5. Insecure Integration With External AI Services

As organizations adopt AI capabilities, applications increasingly rely on external large language models (LLMs), retrieval-augmented generation (RAG) systems, AI agents, plugins, and workflow automation platforms. These integrations extend application functionality, but they also introduce new trust relationships that are often overlooked during development.

The security challenge is rarely the AI model itself. Instead, it lies in how applications consume, process, and act upon AI-generated content. 

During penetration tests, we frequently encounter applications that treat responses from external AI services as inherently trustworthy. Generated outputs are used to populate databases, execute workflows, generate reports, or trigger downstream business processes with little or no validation.

Like any external system, an AI service should be treated as an untrusted source of data. Responses may be manipulated through prompt injection, influenced by malicious user input, affected by inaccurate retrieval results, or simply contain incorrect or unexpected content. If applications consume these responses without verification, the resulting security issues often extend well beyond the AI component itself.

A few years back, users successfully manipulated Chevrolet's ChatGPT-powered customer service chatbot through prompt injection techniques, convincing it to ignore its intended behavior and even offer a new Chevrolet Tahoe for $1

The incident demonstrated that AI-generated responses should never be treated as inherently trustworthy and reinforced the need for validation, business rule enforcement, and human oversight before AI output is used in automated workflows. 

Why Attackers Target It

Attackers are generally less interested in compromising the language model itself than in influencing the systems surrounding it. By crafting malicious prompts or supplying manipulated input, they can alter the model's output in ways that affect downstream application behavior. 

If those responses are trusted without validation, they may trigger unauthorized actions, manipulate business workflows, expose sensitive information, or influence decisions that would otherwise require human approval.

These attacks often resemble traditional security problems rather than AI-specific vulnerabilities. The underlying principle remains unchanged: never assume that data originating from an external service is trustworthy simply because it was generated automatically.

How To Reduce The Risk 

  • Validate AI-generated responses before using them in application logic or automated workflows.
  • Apply authorization and business rule checks regardless of how data is generated.
  • Restrict the permissions granted to AI-powered services using the principle of least privilege.
  • Require human review for actions involving sensitive operations or high-risk business decisions.
  • Log AI interactions and monitor automated workflows for unexpected behavior.
  • Include AI integrations within architecture reviews, threat modeling exercises, and penetration testing.

AI services can generate valuable insights and automate complex tasks, but they should not become trusted decision-makers by default. 

The security of an AI-assisted application depends less on the model itself and more on the controls governing how its output is interpreted, validated, and integrated into the broader application architecture. 

Conclusion

AI-assisted development is transforming how software is built, helping teams deliver features faster and automate routine development tasks. However, the security findings observed during penetration testing show that the fundamentals of application security remain the same.

The vulnerabilities covered in this article, including Broken Access Control, Exposed Secrets, Inconsistent Input Validation, Excessive Data Exposure, and Insecure Integration With External AI Services, are not new. What has changed is the speed at which code is generated and deployed, making it easier for these well-known weaknesses to reach production if security reviews do not keep pace.

Most high-risk findings do not originate from AI-generated code itself. Instead, they result from poor architecture, misplaced trust, inconsistent security controls, and weak business logic. These are decisions that require human judgment and cannot be inferred by AI alone.

AI coding assistants should be viewed as productivity tools, not security tools. Secure architecture reviews, code reviews, automated security testing, and penetration testing remain essential for identifying vulnerabilities before deployment.

Ultimately, secure software is not determined by who, or what, writes the code. It is determined by how thoroughly that code is reviewed, tested, and secured.