Ssh Server Secured

npm version CI/CD License: MIT

A secured fork of zibdie/SSH-MCP-Server with command whitelist/blacklist filtering, network device support, and bulk connection management for safe remote server management via MCP (Model Context Protocol).

Key Features

• Command Whitelist/Blacklist: Control which commands can be executed
• Dangerous Pattern Detection: Blocks fork bombs, command injection, and destructive patterns
• Network Device Support: Cisco, Juniper, MikroTik with persistent shell sessions and enable mode
• Jump Shell Support: SSH into a host then enter a nested CLI (telnet to a host, FreeSWITCH fs_cli, etc.) — commands execute inside the nested shell
• Bulk Connection Management: Load dozens of connections from CSV/JSON files
• Environment Variable Credentials: Passwords auto-resolved from env vars by connectionId — no secrets in chat
• Multi-Connection Execution: Run commands across all or selected connections simultaneously
• Connection Health Monitoring: Keepalive tracking, dead connection detection, auto-cleanup
• Configurable Security Policies: Via config file or environment variables
• Audit Logging: Log all blocked command attempts

Installation

Quick Setup (Recommended)

# Add to Claude CLI
claude mcp add ssh-mcp-secured npx '@marian-craciunescu/ssh-mcp-server-secured@latest'

Manual Installation

npm install -g @marian-craciunescu/ssh-mcp-server-secured

{
  "mcpServers": {
    "ssh-mcp-secured": {
      "command": "ssh-mcp-server-secured"
    }
  }
}

Usage

1. Single Connection

Connect to a host using ssh_connect. You only need to provide host, username, and connectionId — the password is automatically resolved from environment variables:

Connect to host 172.168.0.2 with user admin connectionId=router1

The LLM calls ssh_connect with:

{
  "host": "172.168.0.2",
  "username": "admin",
  "deviceType": "cisco",
  "connectionId": "router1"
}

No password in the tool call. The server automatically looks up ROUTER1_PASSWORD from environment variables.

Credential Resolution Convention

The connectionId is converted to an env var prefix: uppercased, non-alphanumeric characters replaced with _.

connectionId	Env var for password	Env var for enable password
router1	ROUTER1_PASSWORD	ROUTER1_ENABLE_PASSWORD
my-connection	MY_CONNECTION_PASSWORD	MY_CONNECTION_ENABLE_PASSWORD
dc1.switch.3	DC1_SWITCH_3_PASSWORD	DC1_SWITCH_3_ENABLE_PASSWORD

Optionally, <PREFIX>_USERNAME is also resolved if username is not provided.

Set credentials in your MCP configuration:

{
  "mcpServers": {
    "ssh-mcp-secured": {
      "command": "ssh-mcp-server-secured",
      "env": {
        "SSH_FILTER_MODE": "blacklist",
        "ROUTER1_PASSWORD": "admin123",
        "ROUTER1_ENABLE_PASSWORD": "enable123",
        "SERVER1_PASSWORD": "rootpass",
        "SERVER1_USERNAME": "root"
      }
    }
  }
}

Credentials live in the MCP config (or are injected via CI/CD, vault, etc.) and never appear in chat or tool calls. If a password is explicitly provided in the tool call, it takes precedence over the env var.

SSH Options for Legacy Devices

When connecting to older devices that require non-default algorithms (the equivalent of ssh -o), use the sshOptions parameter:

In natural language:

Connect to 10.0.0.1 port 2222 as user, connectionId old-switch, with KexAlgorithms +diffie-hellman-group-exchange-sha1 and HostKeyAlgorithms +ssh-rsa

{
  "host": "10.0.0.1",
  "port": 2222,
  "username": "admin",
  "connectionId": "old-switch",
  "sshOptions": {
    "KexAlgorithms": "+diffie-hellman-group-exchange-sha1",
    "HostKeyAlgorithms": "+ssh-rsa"
  }
}

This is equivalent to:

ssh -p 2222 [email protected] -o KexAlgorithms=+diffie-hellman-group-exchange-sha1 -o HostKeyAlgorithms=+ssh-rsa

Prefix a value with + to append to ssh2 defaults. Without +, the value replaces the defaults entirely.

Option	SSH2 equivalent	Use case
KexAlgorithms	algorithms.kex	Legacy key exchange (e.g. diffie-hellman-group1-sha1)
HostKeyAlgorithms	algorithms.serverHostKey	Legacy host keys (e.g. ssh-rsa, ssh-dss)
Ciphers	algorithms.cipher	Legacy ciphers (e.g. aes128-cbc)
MACs	algorithms.hmac	Legacy MACs (e.g. hmac-sha1)

sshOptions is supported on ssh_connect, ssh_connect_with_jump_command, and JSON files loaded via ssh_load_connections.

Keyboard-interactive auth is enabled automatically (tryKeyboard: true). Legacy devices that reject standard password auth and require keyboard-interactive will work without any extra configuration.

2. Bulk Connections from File

Load multiple connections from a CSV or JSON file using ssh_load_connections. Passwords are resolved from env vars using the same connectionId convention:

CSV format (connections.csv):

host,username,port,deviceType,connectionId
172.168.0.2,admin,22,cisco,router1
10.1.2.15,noc,22,cisco,router2
192.168.1.1,root,22,linux,server1

No passwords in the file. The server resolves ROUTER1_PASSWORD, ROUTER2_PASSWORD, SERVER1_PASSWORD from env vars.

NOTE: CSV can't carry objects so SSH options for legacy devices must be set via individual env vars or in JSON file.

JSON format (connections.json):

[
  {
    "host": "172.168.0.2",
    "username": "admin",
    "deviceType": "cisco",
    "connectionId": "router1"
  },
  {
    "host": "10.1.2.15",
    "username": "noc",
    "deviceType": "cisco",
    "connectionId": "router2",
    "sshOptions": {
      "KexAlgorithms": "+diffie-hellman-group-exchange-sha1",
      "HostKeyAlgorithms": "+ssh-rsa"
    }
  }
]

Profiles: Define reusable connection profiles for connecting to the same type of device with similar settings (e.g. all Cisco switches). Profiles can include default SSH options for legacy devices, so you don't have to repeat them in every connection.

Resolution priority: explicit args > profile env vars > connectionId env vars

export PROFILE_CISCO_USER=admin
export PROFILE_CISCO_PASSWORD=secret123
export PROFILE_CISCO_DEVICE_TYPE=cisco
export PROFILE_CISCO_PORT=2222
export PROFILE_CISCO_SSH_OPTIONS='{"KexAlgorithms":"+diffie-hellman-group-exchange-sha1","HostKeyAlgorithms":"+ssh-rsa"}'

BELOW is an example of how profile env vars are resolved when loading connections from CSV/JSON. The PROFILE_CISCO_SSH_OPTIONS value is parsed as JSON and applied to all connections with deviceType of cisco.

Env Var Example	Field	Value
PROFILE_CISCO_USER	username	admin
PROFILE_CISCO_PASSWORD	password	secret123
PROFILE_CISCO_DEVICE_TYPE	deviceType	cisco
PROFILE_CISCO_SSH_OPTIONS	sshOptions (parsed as JSON)	{"KexAlgorithms":"+diffie-hellman-group-exchange-sha1","HostKeyAlgorithms":"+ssh-rsa"}
PROFILE_CISCO_JUMP_COMMAND	jumpCommand	telnet lh
PROFILE_CISCO_PRESET	preset	topex
PROFILE_CISCO_PORT	port	2222
PROFILE_CISCO_WHITELIST	per-profile command whitelist (comma-separated or JSON array)	show ospf neigh,show version
PROFILE_CISCO_BLACKLIST	per-profile command blacklist (comma-separated or JSON array)	show running config,conf t
PROFILE_CISCO_DISABLE_PAGER	per-profile pager toggle (true/false)	false

ssh_connect host=10.0.0.1 profile=CISCO connectionId=SWITCH1"

Per-Profile Command Filtering

In addition to the global SSH_WHITELIST / SSH_BLACKLIST, each profile can carry its own command filter via PROFILE_<NAME>_WHITELIST and PROFILE_<NAME>_BLACKLIST. These are layered on top of the global filter at execution time for any connection opened with that profile:

• Profile blacklist always blocks — even commands the global filter would allow (e.g. block show running config).
• Profile whitelist re-allows specific commands and, when present, becomes authoritative: anything not listed is blocked (e.g. allow show ospf neigh while the blacklist still blocks the rest).
• On direct conflict, the blacklist wins.

export PROFILE_ROUTERS_BLACKLIST="show running config,conf t,configure terminal"
export PROFILE_ROUTERS_WHITELIST="show ospf neigh,show version,show ip interface brief"

ssh_connect host=10.0.0.1 profile=ROUTERS connectionId=router1
# show ospf neigh        → allowed (profile whitelist)
# show running config    → blocked (profile blacklist)

PROFILE_<NAME>_DISABLE_PAGER=false turns off pager suppression for connections using that profile, overriding the global SSH_DISABLE_PAGER default.

Usage:

Load connections from /path/to/connections.csv and connect to all

Note: You can still provide passwords directly in CSV/JSON if preferred — env var resolution only kicks in when the password field is missing or empty.

3. Network Device Types

The server supports different device types with appropriate connection handling:

Device Type	Behavior	Use Case
linux	Standard SSH exec mode (default)	Linux/Unix servers
cisco	Persistent shell, enable mode support	Cisco IOS/IOS-XE routers and switches
juniper	Persistent shell	Juniper JunOS devices
mikrotik	Persistent shell	MikroTik RouterOS
network	Generic persistent shell	Other network devices
jump_shell	Persistent shell + nested CLI	Used internally by ssh_connect_with_jump_command

Network devices use PTY-allocated persistent shell sessions instead of standard exec() because many network operating systems close the SSH channel after each exec command.

4. Cisco Enable Mode

Enter privileged EXEC mode on Cisco devices using ssh_cisco_enable:

{
  "connectionId": "router1"
}

The tool handles the interactive enable password prompt automatically — it sends enable, waits for Password:, sends the stored enablePassword, and verifies the prompt changed to #.

5. Execute on Multiple Connections

Run a command on specific connections using ssh_execute_on_multiple:

{
  "command": "show version",
  "connectionIds": ["router1", "router2", "switch1"]
}

Or run on ALL connections:

{
  "command": "show ip interface brief",
  "connectionIds": ["*"]
}

6. Jump Shell (Nested CLI via SSH)

Use ssh_connect_with_jump_command when you need to SSH into a host and then enter a nested interactive shell before executing commands. This covers scenarios like:

• Telnet to a Topex VoIP gateway from an SSH jump host
• FreeSWITCH fs_cli on a remote server
• Any CLI that requires an interactive session after SSH

How it works:

SSH → open shell → send jump command (e.g. "telnet lh") → wait for nested prompt (e.g. "topexsw>") → ready

All subsequent ssh_execute commands on that connectionId run inside the nested shell.

Topex gateway example (with preset):

{
  "host": "10.0.0.1",
  "username": "admin",
  "connectionId": "topex1",
  "preset": "topex",
  "jumpCommand": "telnet lh"
}

The topex preset auto-fills jumpPromptPattern: "topexsw>\\s*$" and jumpExitCommand: "quit". You only need to supply jumpCommand.

Then execute commands inside the Topex CLI:

{
  "command": "view portsoncard *",
  "connectionId": "topex1"
}

FreeSWITCH example (preset fills everything):

{
  "host": "10.0.0.5",
  "username": "root",
  "connectionId": "fs1",
  "preset": "freeswitch"
}

The freeswitch preset auto-fills jumpCommand: "fs_cli", jumpPromptPattern: "freeswitch@...>", and jumpExitCommand: "/exit". Then:

{
  "command": "sofia status",
  "connectionId": "fs1"
}

Fully custom (no preset):

{
  "host": "10.0.0.1",
  "username": "admin",
  "connectionId": "custom1",
  "jumpCommand": "telnet 192.168.1.100",
  "jumpPromptPattern": ">\\s*$",
  "jumpExitCommand": "quit",
  "jumpReadyTimeout": 8000
}

Built-in presets:

Preset	jumpCommand	Prompt pattern	Exit command
freeswitch	fs_cli	freeswitch@...>	/exit
topex	(user provides)	topexsw>	quit

Presets can be overridden — any explicitly provided parameter takes precedence.

Shell recovery: If the shell drops, ssh_execute automatically reopens the shell and re-enters the jump shell.

Disconnect: ssh_disconnect gracefully sends the exit command to the nested CLI before closing the SSH connection.

7. Logging

Set log level via environment variable:

Variable	Values	Default
SSH_LOG_LEVEL	DEBUG, INFO, WARN, ERROR	INFO
SSH_LOG_FILE	Path to log file	(none)

Log format:

[2026-01-22T20:26:02.044Z] [INFO ] ✓ SSH connection established to 172.168.0.2:22
[2026-01-22T20:26:02.046Z] [DEBUG] ♥ Keepalive #1 sent to 172.168.0.2 | {"uptime":"10s"}
[2026-01-22T20:26:12.047Z] [WARN ] ⚠ CONNECTION CLOSED BY REMOTE HOST: router1

Configuration

Environment Variables

Variable	Values	Default	Description
SSH_FILTER_MODE	whitelist, blacklist, disabled	blacklist	Command filtering mode
SSH_ALLOW_SUDO	true, false	true	Allow sudo commands
SSH_LOG_BLOCKED	true, false	true	Log blocked commands to stderr
SSH_MCP_CONFIG	file path	-	Path to config JSON file
SSH_WHITELIST	comma-separated or JSON	-	Override whitelist commands
SSH_BLACKLIST	comma-separated or JSON	-	Override blacklist commands
SSH_DANGEROUS_PATTERNS	JSON array	-	Override dangerous regex patterns
SSH_LOG_LEVEL	DEBUG, INFO, WARN, ERROR	INFO	Log verbosity
SSH_LOG_FILE	path	-	Log to file
SSH_HOST_FILTER_MODE	whitelist, blacklist, disabled	disabled	Host filtering mode
SSH_HOST_WHITELIST	comma-separated IPs	-	Whitelist of allowed host IPs
SSH_HOST_BLACKLIST	comma-separated IPs	-	Blacklist of allowed host IPs
SSH_IDLE_TIMEOUT	seconds	120	Idle connection timeout
SSH_FAILED_CONNECTIONS_LOG	file path	./ssh-failed-connections.json	/var/log/ssh-failed.jsonl
SSH_AUDIT_ENABLED	true, false	true	Write a per-command session audit (command + full output) to JSONL
SSH_AUDIT_DIR	path	./audit	Directory for daily audit_YYYY-MM-DD.jsonl files
SSH_ENABLE_LARGE_OUTPUT	true, false	false	Offload oversized command output to an upload endpoint and return a URI instead of inline text
SSH_MAX_OUTPUT_LENGTH	integer (chars)	10000	Output size threshold above which output is offloaded
SSH_FILE_UPLOAD_ENDPOINT	URL	-	POST target for large output. Receives {content, filename}, must return {file_id, artifact_uri}
SSH_DISABLE_PAGER	true, false	true	Suppress interactive pagers (less/---(more)---) on shell and exec
SSH_DISABLE_PAGER_CMD_<DEVICETYPE>	string	per-device default	Override the disable-pager command for a device type (e.g. SSH_DISABLE_PAGER_CMD_CISCO)
SSH_PAGER_REGEX	regex string	built-in	Override the pattern used to detect a pager prompt
SSH_PAGER_ADVANCE_KEY	string	" " (space)	Key sent to advance to the next pager page
SSH_MAX_PAGER_PAGES	integer	1000	Safety cap on auto-paged pages per command

Any additional environment variables following the <CONNECTIONID>_PASSWORD convention are automatically used for credential resolution (see Credential Resolution Convention).

MCP Configuration Examples

Host whitelist/blacklist:

Blacklist mode with custom blocked commands:

{
  "ssh_mcp": {
    "command": "ssh-mcp-server-secured",
    "args": [],
    "env": {
      "SSH_FILTER_MODE": "blacklist",
      "SSH_ALLOW_SUDO": "true",
      "SSH_LOG_BLOCKED": "true",
      "SSH_BLACKLIST": "rm,rmdir,mkfs,fdisk,shutdown,reboot,halt,poweroff,passwd,useradd,userdel,iptables,crontab,conf t,configure terminal"
    }
  }
}

Whitelist mode (strict — only allow specific commands):

{
  "ssh_mcp": {
    "command": "ssh-mcp-server-secured",
    "args": [],
    "env": {
      "SSH_FILTER_MODE": "whitelist",
      "SSH_ALLOW_SUDO": "false",
      "SSH_LOG_BLOCKED": "true",
      "SSH_WHITELIST": "ls,cat,grep,tail,head,df,du,free,uptime,ps,systemctl,journalctl,docker,kubectl,ping,curl,dig,ss,netstat,show,display"
    }
  }
}

Network operations with credential env vars:

{
  "ssh_mcp": {
    "command": "ssh-mcp-server-secured",
    "args": [],
    "env": {
      "SSH_FILTER_MODE": "blacklist",
      "SSH_ALLOW_SUDO": "true",
      "SSH_LOG_LEVEL": "DEBUG",
      "SSH_BLACKLIST": "conf t,configure terminal,rm,shutdown,reboot",
      "ROUTER1_PASSWORD": "admin123",
      "ROUTER1_ENABLE_PASSWORD": "enable123",
      "ROUTER2_PASSWORD": "pass123",
      "SERVER1_PASSWORD": "pass1234"
    }
  }
}

Now in chat you simply say connect to 172.168.0.2 as admin connectionId=router1 — no passwords exposed.

Via npx (no global install):

{
  "ssh_mcp": {
    "command": "npx",
    "args": ["@marian-craciunescu/ssh-mcp-server-secured"],
    "env": {
      "SSH_FILTER_MODE": "blacklist",
      "SSH_ALLOW_SUDO": "true"
    }
  }
}

Config File

Create config.json or ssh-mcp-config.json:

{
  "commandFilter": {
    "mode": "whitelist",
    "allowSudo": false,
    "logBlocked": true,
    "whitelist": [
      "ls", "cat", "grep", "df", "ps", "systemctl", "docker", "show", "ping"
    ],
    "blacklist": [
      "rm", "shutdown", "reboot", "passwd", "conf t", "configure terminal"
    ],
    "dangerousPatterns": [
      ";\\s*rm\\s+-rf",
      "curl.*\\|\\s*bash"
    ]
  }
}

Filter Modes

Blacklist Mode (Default)

Commands in the blacklist are blocked. Everything else is allowed. Supports multi-word entries like configure terminal and conf t.

✓ ls -la
✓ docker ps
✓ show ip interface brief
✗ rm -rf /tmp/files       → Blocked: 'rm' is in blacklist
✗ configure terminal      → Blocked: 'configure terminal' is in blacklist
✗ shutdown now            → Blocked: 'shutdown' is in blacklist

Whitelist Mode

Only commands in the whitelist are allowed. Everything else is blocked.

✓ ls -la                  → Allowed: 'ls' is whitelisted
✓ show version            → Allowed: 'show' is whitelisted
✗ vim /etc/hosts          → Blocked: 'vim' not in whitelist
✗ make install            → Blocked: 'make' not in whitelist

Disabled Mode

No command filtering (use with caution).

Command Validation Order

1. Check if filtering disabled
2. Check sudo permission
3. Check dangerous patterns (regex)
4. Check full command against blacklist (multi-word support)
5. Extract base commands from pipes/chains
6. Check each base command against blacklist/whitelist
7. Apply per-profile (per-connection) whitelist/blacklist on top of the global result

Stable Connection IDs

If you don't pass a connectionId to ssh_connect (or pass default), the server generates a stable, structured id and returns it in the connect response:

<IP>_YYYY_MM_DD_sessionid_<6 random chars>

Example: 10_0_0_1_2026_06_08_sessionid_a1b9f3

The IP dots are replaced with _ so the id is safe to use as an env-var prefix (for <PREFIX>_PASSWORD resolution) and as a filename. Capture the returned connectionId and reuse it for subsequent ssh_execute / ssh_disconnect calls.

Session Audit (command + output)

Every executed command and its output is written as a single JSONL line to a per-day file, separate from server diagnostics (SSH_LOG_FILE):

<SSH_AUDIT_DIR>/audit_YYYY-MM-DD.jsonl

Each record:

{"timestamp":"2026-06-08T11:07:12.569Z","connectionId":"10_0_0_1_2026_06_08_sessionid_a1b9f3","host":"10.0.0.1","command":"show version","exitCode":0,"output":"..."}

Disable with SSH_AUDIT_ENABLED=false.

Large Output Offloading

When a command's output exceeds SSH_MAX_OUTPUT_LENGTH and SSH_ENABLE_LARGE_OUTPUT=true, the full output is POSTed to SSH_FILE_UPLOAD_ENDPOINT and the caller receives a short stub containing the returned artifact_uri and file_id plus a small preview — so a huge show tech-support never floods the model context. The endpoint receives { "content": "...", "filename": "..." } and must return { "file_id": "...", "artifact_uri": "..." }. If the endpoint is unset or the upload fails, output is returned inline as a fallback.

Pager Handling

Interactive pagers (Linux less, Cisco/Juniper ---(more)---) otherwise block a command until it times out. The server handles this two ways:

• Prevention — on shell open it sends a device-appropriate disable-pager command (terminal length 0 for Cisco, set cli screen-length 0 for Juniper), and on Linux exec it sets SYSTEMD_PAGER=, PAGER=cat, GIT_PAGER=cat.
• Detection — if a pager prompt still appears, it auto-advances (sends a space, capped by SSH_MAX_PAGER_PAGES) on network shells, or sends q to quit an interactive Linux pager, then strips the prompt artifacts from the output.

Toggle globally with SSH_DISABLE_PAGER=false, per-profile with PROFILE_<NAME>_DISABLE_PAGER=false, override the command per device type with SSH_DISABLE_PAGER_CMD_<DEVICETYPE>, and override detection with SSH_PAGER_REGEX / SSH_PAGER_ADVANCE_KEY.

Dangerous Patterns

These patterns are always blocked regardless of filter mode:

Pattern	Example	Risk
Fork bomb	:(){ :|:& };:	System crash
Piped rm	find . | rm	Data loss
Chained rm	ls && rm -rf /	Data loss
Device redirect	> /dev/sda	Disk corruption
System config overwrite	> /etc/passwd	System compromise
Remote code execution	curl | bash	Arbitrary code execution
Recursive chmod 777	chmod -R 777 /	Security compromise

Available Tools

Tool	Description
ssh_connect	Connect to a single host (password auto-resolved from <CONNECTIONID>_PASSWORD env var) , supports sshOptions for legacy algorithm negotiation)
ssh_connect_with_jump_command	SSH into a host, then enter a nested CLI (telnet, fs_cli, etc.) via a jump command. Supports presets.
ssh_load_connections	Load connections from CSV/JSON file (credentials resolved from env vars per connectionId)
ssh_execute	Execute a command on one connection
ssh_cisco_enable	Enter Cisco privileged EXEC mode (interactive enable password handling)
ssh_execute_on_multiple	Execute a command on selected connections (["*"] = all)
ssh_disconnect	Disconnect one connection
ssh_disconnect_all	Disconnect all connections
ssh_list_connections	List active connections with status
ssh_check_connections	Health check all connections (dead socket detection, shell status)
ssh_failed_connections	List recent failed connection attempts (from the failed-connections JSONL log)
ssh_upload_file	Upload file via SFTP
ssh_download_file	Download file via SFTP
ssh_list_files	List remote directory via SFTP

Example Workflow

1. Load connections from CSV (passwords auto-resolved from env vars)
   → ssh_load_connections { filePath: "devices.csv", connectAll: true }
   (ROUTER1_PASSWORD, ROUTER2_PASSWORD resolved automatically)

2. Enter enable mode on Cisco routers
   → ssh_cisco_enable { connectionId: "router1" }
   → ssh_cisco_enable { connectionId: "router2" }

3. Execute show commands on all devices
   → ssh_execute_on_multiple {
       command: "show ip interface brief",
       connectionIds: ["*"]
     }

4. Execute privileged command on specific router
   → ssh_execute {
       command: "show running-config | include hostname",
       connectionId: "router1"
     }

5. Check connection health
   → ssh_check_connections {}

6. Connect to a Topex gateway via jump shell
   → ssh_connect_with_jump_command {
       host: "10.0.0.1",
       username: "admin",
       connectionId: "topex1",
       preset: "topex",
       jumpCommand: "telnet lh"
     }

7. Execute command inside the Topex CLI
   → ssh_execute {
       command: "view portsoncard *",
       connectionId: "topex1"
     }

8. Disconnect all
   → ssh_disconnect_all {}

Architecture Notes

Shell Buffer Management

Buffer is cleared before each command. Stability detection uses buffer unchanged for 3 × 500ms = command complete. Password prompts are detected in the last 200 chars of the buffer.

Keepalive System

SSH2 sends keepalives every 10 seconds (keepaliveInterval: 10000). After 3 failed keepalives, the connection auto-closes (keepaliveCountMax: 3). A custom interval logs keepalive count for debugging.

Connection Health Monitoring

The server detects dead connections (socket destroyed), tracks shell status for network devices, auto-cleans dead connections, and attempts shell reopen on network devices if the shell has closed.

Jump Shell

When ssh_connect_with_jump_command is called, the server: (1) opens an SSH connection, (2) opens a PTY shell, (3) sends the jump command (e.g. telnet lh), (4) polls the shell buffer every 300ms for the expected prompt regex, (5) marks the connection as jump_shell with jumpShellActive: true. On disconnect, the nested CLI exit command is sent before closing the SSH session. On shell recovery, the jump command is automatically re-sent.

Environment Variable Credential Resolution

When a connection is created (via ssh_connect or ssh_load_connections), if the password is not provided, the server automatically looks up <PREFIX>_PASSWORD from environment variables, where <PREFIX> is the connectionId uppercased with non-alphanumeric characters replaced by _. The same convention applies to _ENABLE_PASSWORD and _USERNAME. Explicitly provided values always take precedence.

Comparison with Original

Feature	zibdie/SSH-MCP-Server	This Fork
Basic SSH/SFTP	✓	✓
Command whitelist	✗	✓
Command blacklist	✗	✓
Multi-word blacklist entries	✗	✓
Dangerous pattern detection	✗	✓
Audit logging	✗	✓
Command validation tool	✗	✓
Config file support	✗	✓
Network device types (Cisco, Juniper, MikroTik)	✗	✓
Cisco enable mode	✗	✓
Jump shell (nested CLI via SSH)	✗	✓
Bulk connections from CSV/JSON	✗	✓
Multi-connection execution	✗	✓
Environment variable credentials	✗	✓
Connection health monitoring	✗	✓
Keepalive tracking	✗	✓
host/hostname compatibility	✗	✓

Development

# Clone
git clone https://github.com/marian-craciunescu/ssh-mcp-server-secured.git
cd ssh-mcp-server-secured

# Install dependencies
npm install

# Run in development mode
npm run dev

# Test with MCP Inspector
npx @modelcontextprotocol/inspector node index.js

Security Considerations

• Default is blacklist mode — provides protection while remaining flexible
• Dangerous patterns are always checked — even in disabled mode
• Audit logging enabled by default — track blocked attempts
• Sudo can be restricted — set SSH_ALLOW_SUDO=false for high-security environments
• Credential isolation — passwords are resolved from env vars by connectionId, never typed in chat or visible in tool calls

License

MIT — see LICENSE file

Credits

• Original: zibdie/SSH-MCP-Server by Nour Zibdie
• Security fork: marian-craciunescu

Support

• Issues
• Discussions