ssh-keydb – A tool to gather ssh public key information from servers

ssh-keydb is a small tool which connects to a number of ssh servers and saves all available ssh public keys into a json file. This is useful to get an overview which public key is distributed on which server.

Usage

Usage: ssh-keydb [options]

  Options:

    -V, --version               output the version number
    -r, --range <ip/netmask>    (required) IP Range to test
    -H, --hostsfile <file name> (optional) File with host names per line
    -p, --parallel <number>     (optional) Run <number> tests in parallel, default is "1"
    -f, --file <file name>      (optional) File name for key db, default is keydb.json
    -u, --user <user name>      (optional) User name for log in, default is "root"
    -t, --timeout <ms>          (optional) Timeout for handshake in ms, default is "20000"
    -h, --help                  output usage information

Example:

# Test one host
./ssh-keydb.js -r 192.168.232.0/32

# Test 192.168.232.0 - 192.168.232.255
./ssh-keydb.js -r 192.168.232.0/24

# Run 100 ssh connections parallel
./ssh-keydb.js -r 192.168.232.0/24 -p 100

# Reduce timeout for faster testing
./ssh-keydb.js -r 192.168.232.0/24 -p 100 -t 5000

# Read directory with authorized_keys files
./ssh-keydb.js -a ak/

Results

The result is a JSON file in the following format:

{
"AAAAABBBBBCCCCC(ssh public key)": {
    "type": "ssh-rsa",
    "comment": "user@machine",
    "comments": ["user@machine", "other-comment-of-same-key@machine"]
    "servers": [
      "192.168.232.1",
      "192.168.232.2",
      "192.168.232.29",
      ...
    ]
  },
  ...
}

Hints

Use jq to format and filter results

# Pretty print keydb
cat keydb.json  | jq '.'

# Show number of servers per key and sort
cat keydb.json  | jq '.[] | {name: .comment, servers: .servers|length}' | jq --slurp '.|sort_by(.servers)|reverse'

# With all variations of comments
cat keydb.json  | jq '.[] | {names: .comments | join(" | "), servers: .servers|length}' | jq --slurp '.|sort_by(.servers)|reverse'

Get authorized_keys files from a lists of hosts

for i in `cat hosts`; do echo $i; ! test -f ./ak/${i} && scp root@${i}:/root/.ssh/authorized_keys ./ak/$i; done

License

MIT license, have fun!