sast-authorization-testing

name	sast-authorization-testing
description	Investigate authorization vulnerabilities in source code including IDOR, privilege escalation, and missing access controls. Use when threat model identifies CWE-639 (IDOR), CWE-862 (Missing Authorization), CWE-863 (Incorrect Authorization), CWE-269 (Privilege Escalation), or access control concerns.
allowed-tools	Read, Grep, Glob

SAST Authorization Testing Skill

Purpose

Investigate authorization failures in source code by tracing:

• User identity checks (horizontal privilege escalation / IDOR)
• Role/privilege verification (vertical privilege escalation)
• Resource ownership validation rules
• Function-level access controls

Vulnerability Types Covered

1. Insecure Direct Object Reference - IDOR (CWE-639)

User can access other users' resources by manipulating object IDs.

Code Patterns to Find:

• Direct use of user-supplied IDs without ownership checks
• Missing user_id == current_user.id comparisons
• API endpoints accepting resource IDs without authorization

Example Vulnerable Code:

@app.route('/api/user/<int:user_id>')
def get_user(user_id):
    return User.query.get(user_id).to_dict()  # No check if current user can access

2. Vertical Privilege Escalation (CWE-269)

User performs actions requiring higher privileges.

Code Patterns to Find:

• Admin endpoints without role checks
• Missing @admin_required or @role_required decorators
• Role modification endpoints accessible to regular users

Example Vulnerable Code:

@app.route('/admin/delete_user', methods=['POST'])
def delete_user():  # No @admin_required
    User.query.filter_by(id=request.json['id']).delete()

3. Missing Authorization (CWE-862)

Actions execute without ANY authorization check.

Code Patterns to Find:

• API endpoints with no authentication decorator
• Direct database operations without auth context
• Sensitive operations in unauthenticated routes

4. Incorrect Authorization (CWE-863)

Wrong authorization logic applied.

Code Patterns to Find:

• Flawed ownership checks (checking wrong field)
• OR instead of AND in permission checks
• Race conditions in authorization

Investigation Methodology

Step 1: Identify Entry Points

Search for affected routes/endpoints from PR changes:

Grep for: @app.route, @router, def handle_, async def

Step 2: Trace Authorization Decorators

Look for authorization decorators/middleware:

Patterns: @require_auth, @login_required, @admin_only
          @permission_required, @role_required
          authorize!, can?, has_permission

Step 3: Check Ownership Validation

Search for ownership checks in handlers:

Patterns: current_user.id ==, request.user.id
          .filter(user_id=, owner_id=
          belongs_to?, owned_by

Step 4: Cross-Reference with Org

Use github_org_code_search to find:

• How other endpoints implement authz
• Shared auth middleware/decorators
• Common security patterns in the org

Step 5: Verify Data Flow

Trace from user input → database query:

• Is the resource ID validated against user context?
• Can a user access resources they don't own?

Classification Criteria

TRUE_POSITIVE:

• No authorization check exists for sensitive operation
• Ownership check is missing or bypassable
• Role check uses wrong comparison logic

FALSE_POSITIVE:

• Proper authorization decorator exists
• Ownership validation is implemented correctly
• Access is intentionally public

UNVALIDATED:

• Authorization logic is in middleware not visible in PR
• Complex dynamic authorization that can't be statically analyzed

Output Format

### Verdict
- **verdict**: TRUE_POSITIVE or FALSE_POSITIVE
- **confidence_score**: 1-10
- **risk_level**: LOW, MEDIUM, HIGH, or CRITICAL

### Evidence
- **Location**: file:line
- **Issue**: Description of the authorization gap
- **Code**: Relevant code snippet

### Attack Scenario
How an attacker could exploit this:
1. [Steps to reproduce]

### Recommendations
- [Specific fix with code example]

CWE Mapping

• CWE-639: Authorization Bypass Through User-Controlled Key (IDOR)
• CWE-269: Improper Privilege Management
• CWE-862: Missing Authorization
• CWE-863: Incorrect Authorization
• CWE-284: Improper Access Control

Safety Rules

• Only analyze code in the repository provided
• Do not attempt to exploit or test against live systems
• Redact any sensitive data (API keys, secrets) from evidence