# Cwe 284 Improper Access Control

> Use this skill when you need to remediate CWE-284 (Improper Access Control) vulnerabilities in Java code. Triggers on SAST findings, security reviews, or when fixing improper access control issues.

- Skill: `developerscoffee/cwe-284-improper-access-control` (Agent Skill)
- Install (CLI): `npx skillmds@latest add developerscoffee/cwe-284-improper-access-control`
- Raw SKILL.md: https://api.skillmd.com/api/skills/developerscoffee/cwe-284-improper-access-control/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- License: MIT
- Author: DevelopersCoffee (https://skillmd.com/u/developerscoffee)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/developerscoffee/cwe-284-improper-access-control

---


# CWE-284 Improper Access Control

## Description

Improper Access Control

Reference:
https://cwe.mitre.org/data/definitions/284.html


**OWASP Category**: A01:2021 – Broken Access Control


---

## Vulnerable Pattern


### ❌ Example 1: Vulnerable Pattern

```java
// VULNERABLE: No authorization check - IDOR
@GetMapping("/user/{id}/documents")
public List<Document> getUserDocuments(@PathVariable Long id) {
    return documentRepository.findByUserId(id);
}
```


**Why it's vulnerable:** This pattern is vulnerable to Improper Access Control




---

## Deterministic Fix


### ✅ Secure Implementation: Secure Implementation

```java
// SECURE: Verify user can access requested resource
@GetMapping("/user/{id}/documents")
@PreAuthorize("@authService.canAccessUser(#id, authentication)")
public List<Document> getUserDocuments(@PathVariable Long id, Authentication auth) {
    User currentUser = (User) auth.getPrincipal();
    if (!currentUser.getId().equals(id) && !currentUser.hasRole("ADMIN")) {
        throw new AccessDeniedException("Cannot access other user's documents");
    }
    return documentRepository.findByUserId(id);
}
```


**Why it's secure:** Implements proper protection against Improper Access Control




---

## Detection Pattern

Look for these patterns in your codebase:


```bash
# Find endpoints with path variables
grep -rn "@PathVariable" --include="*Controller.java" | grep -v "PreAuthorize"
```



---

## Remediation Steps


1. Verify user is authorized to access each resource

2. Use indirect object references

3. Implement row-level security

4. Log access control failures


---

## Key Imports

```java

import org.springframework.security.access.AccessDeniedException;

import org.springframework.security.core.Authentication;

```

---

## Verification

After remediation:


- Run SAST scanner to confirm vulnerability is resolved

- Review all instances of the vulnerable pattern

- Add unit tests that verify the secure implementation

- Check for similar patterns in related code


---

## Trigger Examples

```
Fix CWE-284 vulnerability
Resolve Improper Access Control issue
Secure this Java code against improper access control
SAST reports CWE-284
```

---

## Common Vulnerable Locations

| Layer | Files | Patterns |
|-------|-------|----------|

| Controller | `*Controller.java` | User input handling |

| Service | `*Service.java` | Business logic |

| Repository | `*Repository.java` | Data access |


---

## References


- [CWE-284: Improper Access Control](https://cwe.mitre.org/data/definitions/284.html)


---

**Source**: Generated by [Java CWE Security Skills Generator](https://github.com/DevelopersCoffee/java-cwe-security-skills)
**Last Updated**: 2026-03-07