# Cwe 306 Missing Authentication

> Use this skill when you need to remediate CWE-306 (Missing Authentication for Critical Function) vulnerabilities in Java code. Triggers on SAST findings, security reviews, or when fixing missing authentication for critical function issues.

- Skill: `developerscoffee/cwe-306-missing-authentication` (Agent Skill)
- Install (CLI): `npx skillmds@latest add developerscoffee/cwe-306-missing-authentication`
- Raw SKILL.md: https://api.skillmd.com/api/skills/developerscoffee/cwe-306-missing-authentication/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-306-missing-authentication

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# CWE-306 Missing Authentication for Critical Function

## Description

Missing Authentication for Critical Function

Reference:
https://cwe.mitre.org/data/definitions/306.html


**OWASP Category**: A07:2021 – Identification and Authentication Failures


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## Vulnerable Pattern


### ❌ Example 1: Vulnerable Pattern

```java
// VULNERABLE: Sensitive operation without auth
@PostMapping("/user/delete/{id}")
public void deleteUser(@PathVariable Long id) {
    userRepository.deleteById(id);
}
```


**Why it's vulnerable:** This pattern is vulnerable to Missing Authentication for Critical Function




---

## Deterministic Fix


### ✅ Secure Implementation: Secure Implementation

```java
// SECURE: Require authentication and authorization
@PostMapping("/user/delete/{id}")
@PreAuthorize("hasRole('ADMIN')")
public void deleteUser(@PathVariable Long id, @AuthenticationPrincipal User user) {
    auditService.log("User deletion by " + user.getUsername());
    userRepository.deleteById(id);
}
```


**Why it's secure:** Implements proper protection against Missing Authentication for Critical Function




---

## Detection Pattern

Look for these patterns in your codebase:


```bash
# Find delete/update operations without auth
grep -rn "delete\\|update\\|create" --include="*Controller.java" | grep -v "PreAuthorize\\|Secured"
```



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## Remediation Steps


1. Identify all critical functions

2. Add authentication requirements to each

3. Implement role-based access control

4. Log all critical operations


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## Key Imports

```java

import org.springframework.security.access.prepost.PreAuthorize;

import org.springframework.security.core.annotation.AuthenticationPrincipal;

```

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## 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-306 vulnerability
Resolve Missing Authentication for Critical Function issue
Secure this Java code against missing authentication for critical function
SAST reports CWE-306
```

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## Common Vulnerable Locations

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

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

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

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


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## References


- [CWE-306: Missing Authentication](https://cwe.mitre.org/data/definitions/306.html)


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