We will use ssh, telnet, nc, openssl, s_client, nmap commands to solve the next 4 levels:

Command Breakdown

1. ssh (Secure Shell)

Definition: Encrypted protocol for secure remote system access and file transfers.

Key Flags:
• -i keyfile - Authenticate using private key file
• -p port - Specify alternate connection port
• -v - Enable verbose mode (debugging)
• -C - Enable compression
• -L - Create local port forward

2. telnet

Definition: Unencrypted TCP/IP communication protocol for terminal access.

Key Flags:
• -l user - Specify login username
• -a - Attempt automatic login
• -e char - Set escape character

3. nc (netcat)

Definition: Network utility for reading/writing TCP/UDP connections.

Key Flags:
• -l - Listen mode (server)
• -p port - Specify source port
• -v - Verbose output
• -n - Skip DNS resolution
• -u - UDP mode

4. openssl s_client

Definition: SSL/TLS client for testing encrypted connections.

Key Flags:
• -connect host:port - Target connection
• -quiet - Suppress non-essential output
• -showcerts - Display full certificate chain
• -servername name - SNI extension
• -CAfile file - Specify CA bundle

5. nmap

Definition: Network exploration and security auditing tool.

Key Flags:
• -p ports - Scan specific ports/ranges
• -sV - Service version detection
• -O - OS fingerprinting
• -T<0-5> - Timing template (0=slowest)
• -A - Aggressive scan (OS/version/script)

bandit13-bandit14

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-quiet suppresses certificate output (shows just the response)

bandit13-bandit-17 walkthrough