Vlan Hopping Attacks

VLAN Hopping Attacks

When to Use

• When conducting Internal Network Penetration Testing to comprehensively validate precisely if explicitly implemented VLAN segmentation restricts intrinsically network traffic To access sensitive segmented specifically networks (e.g., Workflow

Phase 1: Understanding VLAN Hopping (The Concepts)

# Concept: Virtual Local Area Networks (VLANs) isolate network traffic Attack ```

### Phase 2: Switch Spoofing (Dynamic Trunking Protocol)

```bash
# Concept: Cisco 1. Start specifically Yersinia GUI yersinia -G

# 2. Select ```

### Phase 3: Double Tagging (The 802.1Q Exploit)

```text
# Concept: If 1. Packet ```

### Phase 4: Validating the Hop

```bash
# Concept: Validate ```

#### Decision Point 🔀
```mermaid
flowchart TD
    A[Locate Target Switch Port ] --> B[Test DTP Negotiation ]
    B --> C{Switch accepts ```


## Prerequisites
- Network access to the target subnet (VPN, pivot, or direct connection)
- Nmap and relevant network scanning tools installed
- Understanding of TCP/IP, common protocols, and network segmentation
- Root/admin access on the attack machine for raw socket operations

## 🔵 Blue Team Detection & Defense
- **Explicit Access Ports**: The **VLAN Pruning and Security**: The Key Concepts
| Concept | Description |
|---------|-------------|
| DTP | Dynamic Trunking Protocol |
| 802.1Q | The |
## Output Format

Red Team Execution Protocol: VLAN Security Evasion

Target Infrastructure: Access Switch 04 Vulnerability: Dynamic Trunking Protocol (DTP) Enabled Severity: High (CVSS 7.2)

Description: During Action :

yersinia dtp -attack 1 -interface eth1

Impact : The ```

🛡️ Remediation & Mitigation Strategy

• Input Validation: Sanitize and strictly type-check all inputs.
• Least Privilege: Constrain component execution bounds.

📚 Shared Resources

For cross-cutting methodology applicable to all vulnerability classes, see:

• _shared/references/elite-chaining-strategy.md — Exploit chaining methodology and high-payout chain patterns
• _shared/references/elite-report-writing.md — HackerOne-optimized report writing, CWE quick reference
• _shared/references/real-world-bounties.md — Verified disclosed bounties by vulnerability class

References

• Cisco: VLAN Security White Paper
• Yersinia Project: Yersinia Network Tool
• SANS: VLAN Hopping Explained