TACACS Pentesting

Default Port: 49

TACACS (Terminal Access Controller Access-Control System) is a protocol used to manage access to network devices and servers. TACACS+ is a more secure and advanced version that provides authentication, authorization, and accounting.

Connect

Connect Using TACACS Client

You can connect to a TACACS server using a TACACS client. For example, on Linux systems, you can use the TACACS client with the following command:

tacacs_client -u <username> -p <password> -a <TACACS-server-ip>

This command allows you to connect to a specific TACACS server with a given username and password.

Recon

Identifying a TACACS Server

You can use Nmap to check if there is a TACACS service running on a specific host:

nmap -p 49 X.X.X.X

This command checks if there is a service running on port 49 of the specified IP address.

Banner Grabbing

You can use Netcat or a similar tool to perform banner grabbing and retrieve information about the TACACS service:

nc -nv X.X.X.X 49

This command collects banner information from the service running on port 49 of the given IP address.

Enumeration

TACACS+ Packet Analysis

You can use packet analysis tools like Wireshark to capture and analyze TACACS+ packets. TACACS+ traffic operates over TCP port 49.

Enumerating TACACS Users

There may be methods to enumerate TACACS users and groups, although it typically requires proper authorization. If you gain access, you can attempt to retrieve user and group details.

Attack Vectors

Default Credentials

Check for default credentials or weak authentication configurations. For example, try common password combinations like admin:admin123 or admin:<blank>.

Brute Force Attacks

You can perform brute-force attacks to guess weak passwords using tools like hydra:

hydra -l admin -P /path/to/passwords.txt <target_ip> -s 49 tacacs

Unauthorized Access

Exploit misconfigured access controls or weak authentication mechanisms to gain unauthorized access.

Post-Exploitation

Privilege Escalation

After gaining unauthorized access, try various methods to escalate privileges to higher-level accounts.

Data Analysis and Manipulation

Once you have access to sensitive data on network devices, you can analyze or manipulate this data.

User Session Hijacking

Target and hijack active user sessions to capture session information and manipulate sessions to your advantage.

Example of TACACS CLI Commands (Hypothetical)

Command	Description
tacacs_client -l <entity>\	List entities like users or sessions.
tacacs_client -i <entity>\ -u <user>\	Display detailed information about a specific user.
tacacs_client -a <entity>\ -n <name>\	Add a new user/entity to TACACS.
tacacs_client -d <entity>\ -u <user>\	Delete an existing user/entity from TACACS.

These commands are typically used for managing TACACS, and you can use them after gaining unauthorized access.